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[PATCH v9 2/4] Move page-reader out of XLogReadRecord 52+ messages / 3 participants [nested] [flat]
* [PATCH v9 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 11 +- src/backend/access/transam/xlog.c | 54 +- src/backend/access/transam/xlogreader.c | 681 +++++++++++------- src/backend/access/transam/xlogutils.c | 12 +- src/backend/replication/logical/logical.c | 17 +- .../replication/logical/logicalfuncs.c | 8 +- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 13 +- src/bin/pg_rewind/parsexlog.c | 81 ++- src/bin/pg_waldump/pg_waldump.c | 24 +- src/include/access/xlogreader.h | 90 +-- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 9 +- 13 files changed, 601 insertions(+), 411 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 2f7d4ed59a..24b08810ac 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,8 +1330,7 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - &read_local_xlog_page, NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL); if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1339,7 +1338,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index b0ad9376d6..e380eaa186 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -827,13 +827,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -908,8 +901,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1221,8 +1214,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - NULL, NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL); if (!debug_reader) { @@ -4322,15 +4314,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4338,8 +4325,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6309,7 +6304,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6465,9 +6459,7 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - &XLogPageRead, &private); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL); if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11810,12 +11802,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11858,8 +11851,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -11964,6 +11957,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 6250093dd9..7c8c6fc314 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -70,8 +70,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) * Returns NULL if the xlogreader couldn't be allocated. */ XLogReaderState * -XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogPageReadCB pagereadfunc, void *private_data) +XLogReaderAllocate(int wal_segment_size, const char *waldir) { XLogReaderState *state; @@ -102,9 +101,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - state->read_page = pagereadfunc; - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -242,6 +238,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -250,314 +247,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the read_page callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->read_page(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->read_page(state, state->readPagePtr, state->readLen, - state->ReadRecPtr, state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->read_page(state, state->readPagePtr, state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -565,7 +700,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -718,11 +854,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -740,7 +877,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -972,11 +1109,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1009,8 +1149,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->read_page(state, state->readPagePtr, state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1062,8 +1201,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 2464a0d092..82f1ed2d1a 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -823,9 +822,11 @@ wal_segment_open(XLogSegNo nextSegNo, WALSegmentContext * segcxt, * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -943,6 +944,7 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 5adf253583..7782e3ad2f 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,7 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogPageReadCB read_page, + LogicalDecodingXLogReadPageCB read_page, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +169,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, read_page, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->read_page = read_page; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -230,7 +231,7 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogPageReadCB read_page, + LogicalDecodingXLogReadPageCB read_page, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -372,7 +373,7 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogPageReadCB read_page, + LogicalDecodingXLogReadPageCB read_page, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -479,7 +480,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->read_page(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f5384f1df8..8f2b2dd1fe 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -269,7 +269,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->read_page(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index f776de3df7..bd34042458 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -489,7 +489,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->read_page(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index e1c1de22c5..0dab43545d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -799,9 +799,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -2834,7 +2836,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->read_page(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 6cbe108129..86b6540057 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,19 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, &SimpleXLogPageRead, - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -112,18 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, &SimpleXLogPageRead, - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -158,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -174,10 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, &SimpleXLogPageRead, - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -187,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -234,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -270,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -290,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -304,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -346,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 33fde23e7b..1c42050277 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -324,10 +324,12 @@ WALDumpOpenSegment(XLogSegNo nextSegNo, WALSegmentContext *segcxt, * XLogReader read_page callback */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -366,6 +368,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1033,13 +1036,14 @@ main(int argc, char **argv) /* done with argument parsing, do the actual work */ /* we have everything we need, start reading */ - xlogreader_state = XLogReaderAllocate(WalSegSz, waldir, WALDumpReadPage, - &private); + xlogreader_state = XLogReaderAllocate(WalSegSz, waldir); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1063,7 +1067,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6ad953eea3..e59e42bee3 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -50,13 +50,6 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); - typedef struct { /* Is this block ref in use? */ @@ -86,6 +79,29 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* ---------------------------------------- @@ -93,46 +109,20 @@ struct XLogReaderState * ---------------------------------------- */ - /* - * Data input callback (mandatory). - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB read_page; - /* * System identifier of the xlog files we're about to read. Set to zero * (the default value) if unknown or unimportant. */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -146,7 +136,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -186,8 +178,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -214,15 +204,22 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, - const char *waldir, - XLogPageReadCB pagereadfunc, - void *private_data); + const char *waldir); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -252,12 +249,17 @@ extern void WALOpenSegmentInit(WALOpenSegment *seg, WALSegmentContext *segcxt, /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index dc7d894e5d..312acb4fa3 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index 3b7ca7f1da..cbe9ed751c 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogReadPageCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogReadPageCB read_page; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,14 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogPageReadCB read_page, + LogicalDecodingXLogReadPageCB read_page, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogPageReadCB read_page, + LogicalDecodingXLogReadPageCB read_page, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.2 ----Next_Part(Wed_Apr_22_10_12_46_2020_740)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v9-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v13 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 11 +- src/backend/access/transam/xlog.c | 54 +- src/backend/access/transam/xlogreader.c | 693 +++++++++++------- src/backend/access/transam/xlogutils.c | 12 +- src/backend/replication/logical/logical.c | 17 +- .../replication/logical/logicalfuncs.c | 14 +- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 14 +- src/bin/pg_rewind/parsexlog.c | 69 +- src/bin/pg_waldump/pg_waldump.c | 24 +- src/include/access/xlogreader.h | 90 +-- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 9 +- src/include/replication/logicalfuncs.h | 5 +- 14 files changed, 605 insertions(+), 419 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 5adf956f41..f5f6278880 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,8 +1330,7 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - &read_local_xlog_page, NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL); if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1339,7 +1338,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 357432ffa2..9d5d71ac8c 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -802,13 +802,6 @@ static XLogSource readSource = 0; /* XLOG_FROM_* code */ static XLogSource currentSource = 0; /* XLOG_FROM_* code */ static bool lastSourceFailed = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -883,8 +876,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, int source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, int source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1193,8 +1186,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - NULL, NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL); if (!debug_reader) { @@ -4256,15 +4248,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4272,8 +4259,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6213,7 +6208,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6368,9 +6362,7 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - &XLogPageRead, &private); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL); if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11586,12 +11578,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11634,8 +11627,8 @@ retry: receivedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -11740,6 +11733,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 2c1500443e..ad85f50c77 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -70,8 +70,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) * Returns NULL if the xlogreader couldn't be allocated. */ XLogReaderState * -XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogPageReadCB pagereadfunc, void *private_data) +XLogReaderAllocate(int wal_segment_size, const char *waldir) { XLogReaderState *state; @@ -102,9 +101,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - state->read_page = pagereadfunc; - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -239,6 +235,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -247,314 +244,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the read_page callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. - */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) -{ - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. + */ +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) +{ + XLogRecord *prec; + + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) + switch (state->readRecordState) { - /* read the record after the one we just read */ + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->read_page(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) - { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->read_page(state, state->readPagePtr, state->readLen, - state->ReadRecPtr, state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); - - /* Check that the continuation on next page looks valid */ - pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } + pageHeader = (XLogPageHeader) state->readBuf; + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) + { + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* XLogNeedData has verified the page header */ + Assert(pageHeaderSize <= state->readLen); + + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; + + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + else + { + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); + goto err; + } + } + /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ + + case XLREAD_FIRST_FRAGMENT: + { + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; - Assert(pageHeaderSize <= state->readLen); + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; - - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; - - /* If we just reassembled the record header, validate it. */ - if (!gotheader) - { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) - goto err; - gotheader = true; - } - } while (gotlen < total_len); - - Assert(gotheader); - - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; - - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) - { - if (!state->read_page(state, state->readPagePtr, state->readLen, - state->ReadRecPtr, state->readBuf)) - break; + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ - if (!state->page_verified) - goto err; + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; - state->ReadRecPtr = RecPtr; + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); + + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } + + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); + + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -562,7 +697,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -715,11 +851,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -737,7 +874,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -969,11 +1106,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1006,8 +1146,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->read_page(state, state->readPagePtr, state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1059,8 +1198,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 47676bf800..b2c2abc826 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -685,8 +685,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -701,7 +700,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -819,9 +818,11 @@ wal_segment_open(XLogSegNo nextSegNo, WALSegmentContext * segcxt, * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -939,6 +940,7 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index cf93200618..d0a002fae7 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,7 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogPageReadCB read_page, + LogicalDecodingXLogReadPageCB read_page, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +169,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, read_page, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->read_page = read_page; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -228,7 +229,7 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogPageReadCB read_page, + LogicalDecodingXLogReadPageCB read_page, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -370,7 +371,7 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogPageReadCB read_page, + LogicalDecodingXLogReadPageCB read_page, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -477,7 +478,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->read_page(ctx)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index acc8ef73be..8158842432 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -107,11 +107,9 @@ check_permissions(void) } bool -logical_read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +logical_read_local_xlog_page(LogicalDecodingContext *ctx) { - return read_local_xlog_page(state, targetPagePtr, reqLen, - targetRecPtr, cur_page); + return read_local_xlog_page(ctx->reader); } /* @@ -279,7 +277,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->read_page(ctx)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 7c89694611..ccf96134a7 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -428,7 +428,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->read_page(ctx)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 9f8e5a592d..b9b3f07cad 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -763,9 +763,12 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(LogicalDecodingContext *ctx) { + XLogReaderState *state = ctx->reader; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -2794,7 +2797,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->read_page(logical_decoding_ctx)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 78ee9f3faa..55337b65f1 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -39,14 +39,8 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -60,18 +54,20 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, &SimpleXLogPageRead, - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex)) + break; + } if (record == NULL) { @@ -108,17 +104,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex) XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, &SimpleXLogPageRead, - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex)) + break; + } if (record == NULL) { if (errormsg) @@ -153,7 +151,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -169,9 +166,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, &SimpleXLogPageRead, - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -181,7 +176,12 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex)) + break; + } if (record == NULL) { @@ -228,10 +228,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -264,14 +265,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -316,7 +317,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index fcfe80730c..e82f184de2 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -323,10 +323,12 @@ WALDumpOpenSegment(XLogSegNo nextSegNo, WALSegmentContext *segcxt, * XLogReader read_page callback */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -365,6 +367,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1025,13 +1028,14 @@ main(int argc, char **argv) /* done with argument parsing, do the actual work */ /* we have everything we need, start reading */ - xlogreader_state = XLogReaderAllocate(WalSegSz, waldir, WALDumpReadPage, - &private); + xlogreader_state = XLogReaderAllocate(WalSegSz, waldir); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1055,7 +1059,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6ad953eea3..e59e42bee3 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -50,13 +50,6 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); - typedef struct { /* Is this block ref in use? */ @@ -86,6 +79,29 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* ---------------------------------------- @@ -93,46 +109,20 @@ struct XLogReaderState * ---------------------------------------- */ - /* - * Data input callback (mandatory). - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB read_page; - /* * System identifier of the xlog files we're about to read. Set to zero * (the default value) if unknown or unimportant. */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -146,7 +136,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -186,8 +178,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -214,15 +204,22 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, - const char *waldir, - XLogPageReadCB pagereadfunc, - void *private_data); + const char *waldir); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -252,12 +249,17 @@ extern void WALOpenSegmentInit(WALOpenSegment *seg, WALSegmentContext *segcxt, /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index dc7d894e5d..312acb4fa3 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index 3b7ca7f1da..f0ccfc6895 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogReadPageCB)(LogicalDecodingContext *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogReadPageCB read_page; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,14 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogPageReadCB read_page, + LogicalDecodingXLogReadPageCB read_page, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogPageReadCB read_page, + LogicalDecodingXLogReadPageCB read_page, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); diff --git a/src/include/replication/logicalfuncs.h b/src/include/replication/logicalfuncs.h index ab7941a155..6a477d0930 100644 --- a/src/include/replication/logicalfuncs.h +++ b/src/include/replication/logicalfuncs.h @@ -11,9 +11,6 @@ #include "replication/logical.h" -extern bool logical_read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, - char *cur_page); +extern bool logical_read_local_xlog_page(LogicalDecodingContext *ctx); #endif -- 2.18.2 ----Next_Part(Tue_Jan_28_21_20_20_2020_871)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v13-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v8 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 11 +- src/backend/access/transam/xlog.c | 54 +- src/backend/access/transam/xlogreader.c | 681 +++++++++++------- src/backend/access/transam/xlogutils.c | 12 +- src/backend/replication/logical/logical.c | 17 +- .../replication/logical/logicalfuncs.c | 8 +- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 13 +- src/bin/pg_rewind/parsexlog.c | 80 +- src/bin/pg_waldump/pg_waldump.c | 24 +- src/include/access/xlogreader.h | 90 +-- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 9 +- 13 files changed, 601 insertions(+), 410 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 2f7d4ed59a..24b08810ac 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,8 +1330,7 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - &read_local_xlog_page, NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL); if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1339,7 +1338,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index b0ad9376d6..e380eaa186 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -827,13 +827,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -908,8 +901,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1221,8 +1214,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - NULL, NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL); if (!debug_reader) { @@ -4322,15 +4314,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4338,8 +4325,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6309,7 +6304,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6465,9 +6459,7 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - &XLogPageRead, &private); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL); if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11810,12 +11802,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11858,8 +11851,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -11964,6 +11957,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 6250093dd9..7c8c6fc314 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -70,8 +70,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) * Returns NULL if the xlogreader couldn't be allocated. */ XLogReaderState * -XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogPageReadCB pagereadfunc, void *private_data) +XLogReaderAllocate(int wal_segment_size, const char *waldir) { XLogReaderState *state; @@ -102,9 +101,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - state->read_page = pagereadfunc; - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -242,6 +238,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -250,314 +247,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the read_page callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->read_page(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->read_page(state, state->readPagePtr, state->readLen, - state->ReadRecPtr, state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->read_page(state, state->readPagePtr, state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -565,7 +700,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -718,11 +854,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -740,7 +877,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -972,11 +1109,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1009,8 +1149,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->read_page(state, state->readPagePtr, state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1062,8 +1201,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 2464a0d092..82f1ed2d1a 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -823,9 +822,11 @@ wal_segment_open(XLogSegNo nextSegNo, WALSegmentContext * segcxt, * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -943,6 +944,7 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 5adf253583..7782e3ad2f 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,7 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogPageReadCB read_page, + LogicalDecodingXLogReadPageCB read_page, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +169,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, read_page, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->read_page = read_page; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -230,7 +231,7 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogPageReadCB read_page, + LogicalDecodingXLogReadPageCB read_page, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -372,7 +373,7 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogPageReadCB read_page, + LogicalDecodingXLogReadPageCB read_page, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -479,7 +480,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->read_page(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f5384f1df8..8f2b2dd1fe 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -269,7 +269,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->read_page(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index f776de3df7..bd34042458 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -489,7 +489,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->read_page(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index e1c1de22c5..0dab43545d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -799,9 +799,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -2834,7 +2836,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->read_page(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 1b0199f52f..5b16681a37 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,19 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, &SimpleXLogPageRead, - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -111,17 +108,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex) XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, &SimpleXLogPageRead, - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, NULL)) + break; + } if (record == NULL) { if (errormsg) @@ -156,7 +155,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -172,10 +170,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, &SimpleXLogPageRead, - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -185,7 +180,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -232,10 +233,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -268,14 +270,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -288,7 +290,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -302,7 +304,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -344,7 +346,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 33fde23e7b..1c42050277 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -324,10 +324,12 @@ WALDumpOpenSegment(XLogSegNo nextSegNo, WALSegmentContext *segcxt, * XLogReader read_page callback */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -366,6 +368,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1033,13 +1036,14 @@ main(int argc, char **argv) /* done with argument parsing, do the actual work */ /* we have everything we need, start reading */ - xlogreader_state = XLogReaderAllocate(WalSegSz, waldir, WALDumpReadPage, - &private); + xlogreader_state = XLogReaderAllocate(WalSegSz, waldir); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1063,7 +1067,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6ad953eea3..e59e42bee3 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -50,13 +50,6 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); - typedef struct { /* Is this block ref in use? */ @@ -86,6 +79,29 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* ---------------------------------------- @@ -93,46 +109,20 @@ struct XLogReaderState * ---------------------------------------- */ - /* - * Data input callback (mandatory). - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB read_page; - /* * System identifier of the xlog files we're about to read. Set to zero * (the default value) if unknown or unimportant. */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -146,7 +136,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -186,8 +178,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -214,15 +204,22 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, - const char *waldir, - XLogPageReadCB pagereadfunc, - void *private_data); + const char *waldir); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -252,12 +249,17 @@ extern void WALOpenSegmentInit(WALOpenSegment *seg, WALSegmentContext *segcxt, /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index dc7d894e5d..312acb4fa3 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index 3b7ca7f1da..cbe9ed751c 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogReadPageCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogReadPageCB read_page; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,14 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogPageReadCB read_page, + LogicalDecodingXLogReadPageCB read_page, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogPageReadCB read_page, + LogicalDecodingXLogReadPageCB read_page, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.2 ----Next_Part(Tue_Apr_21_17_04_27_2020_275)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v8-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v19 2/5] Move page-reader out of XLogReadRecord(). @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from the WAL decoder. XLogReadRecord() return XLREAD_NEED_DATA to indicate that the caller should supply new data, and the decoder works as a state machine. Author: Kyotaro HORIGUCHI <[email protected]> Author: Heikki Linnakangas <[email protected]> Reviewed-by: Antonin Houska <[email protected]> Reviewed-by: Alvaro Herrera <[email protected]> Reviewed-by: Takashi Menjo <[email protected]> Reviewed-by: Thomas Munro <[email protected]> Discussion: https://postgr.es/m/20190418.210257.43726183.horiguchi.kyotaro%40lab.ntt.co.jp --- src/backend/access/transam/twophase.c | 14 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 690 ++++++++++-------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 122 ++-- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 628 insertions(+), 499 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 89335b64a2..3137cb3ecc 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) char *errormsg; TimeLineID save_currtli = ThisTimeLineID; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,12 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } /* * Restore immediately the timeline where it was previously, as diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 8085ca1117..b7d7e6d31b 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -838,13 +838,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -920,8 +913,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1234,8 +1227,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4369,15 +4361,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4385,8 +4372,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6456,7 +6451,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6615,13 +6609,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -12107,12 +12097,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12155,8 +12146,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12261,6 +12252,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index f2345ab09e..661863e94b 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,12 +253,12 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * * Returns XLREAD_NEED_DATA if more data is needed to finish reading the * current record. In that case, state->readPagePtr and state->readLen inform @@ -304,307 +303,410 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * state. This behavior allows to continue reading a reacord switching among * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) + switch (state->readRecordState) { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) - { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) + { + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the + * header size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ + } + + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the + * page, the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + pageHeader = (XLogPageHeader) state->readBuf; + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) + { + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* XLogNeedData has verified the page header */ + Assert(pageHeaderSize <= state->readLen); + + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the + * whole record header might not fit on this page. xl_tot_len + * is the first field of the struct, so it must be on this + * page (the records are MAXALIGNed), but we cannot access any + * other fields until we've verified that we got the whole + * header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; + + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after + * reading it from the next page. The xl_tot_len check is + * necessary here to ensure that we enter the + * XLREAD_CONTINUATION state below; otherwise we might fail to + * apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + else + { + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); + goto err; + } + } + + /* + * Wait for the rest of the record, or the part of the record + * that fit on the first page if crossed a page boundary, to + * become available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ + + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert(targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; - } + } - if (!state->page_verified) - goto err; + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); - Assert(SizeOfXLogShortPHD <= state->readLen); + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ - pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) - { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) + case XLREAD_CONTINUATION: { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); + /* + * we enter this state only if we haven't read the whole + * record. + */ + Assert(state->recordRemainLen > 0); - Assert(pageHeaderSize <= state->readLen); + while (state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; - Assert(pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* this request contains page header */ + Assert(targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) - { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); + + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* + * Cross-check that xlp_rem_len agrees with how much of + * the record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } + + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); + + /* + * XLogNeedData should have ensured that the whole page + * header was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* + * XLogNeedData should have ensured all needed data was + * read + */ + Assert(state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* + * Calculate pointer to beginning of next page, and + * continue + */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) goto err; - gotheader = true; - } - } while (gotlen < total_len); - - Assert(gotheader); - - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; - - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) - { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; - } - - if (!state->page_verified) - goto err; - - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; - - state->EndRecPtr = RecPtr + MAXALIGN(total_len); - - state->ReadRecPtr = RecPtr; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert(!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -612,7 +714,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -764,11 +867,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -785,7 +889,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -1015,11 +1119,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1052,9 +1159,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while (XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1106,8 +1211,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1127,9 +1240,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1142,6 +1255,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1173,10 +1287,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 2f6803637b..4f6e87f18d 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 01d354829b..8f8c129620 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index d9d36879ed..7ab0b804e4 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index a4d6f30957..b024bbc3cd 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 75ece5c658..c4047b92b5 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1044,16 +1050,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1076,7 +1080,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 5d9e0d3292..1492f1992d 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,36 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState +{ + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +137,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -186,7 +157,9 @@ struct XLogReaderState * read by reader, which must be larger than * the request, or -1 on error */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified; /* is the current record header verified? */ + /* ---------------------------------------- @@ -228,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -256,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState; /* state machine state */ + int recordGotLen; /* amount of current record that has already + * been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -263,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -273,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -298,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index e28c990382..bd9a5c6c2b 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -384,7 +384,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index af551d6f4e..94e278ef81 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Wed_Apr__7_17_50_25_2021_942)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v19-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v16 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 701 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 649 insertions(+), 489 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index ef4f9981e3..9a56b3487e 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1324,11 +1324,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1336,7 +1333,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index a91e86b290..6ef1f817ad 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -828,13 +828,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -909,8 +902,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1222,8 +1215,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4323,15 +4315,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4339,8 +4326,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6317,7 +6312,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6477,13 +6471,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11866,12 +11856,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11914,8 +11905,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12020,6 +12011,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index f403261626..d829e57baa 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,318 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -573,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -725,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -747,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -979,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1016,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1070,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1091,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1106,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1137,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 4c6d072720..c43812ee94 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -688,8 +688,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -704,7 +703,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -791,6 +790,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -828,9 +828,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -943,11 +945,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 0f6af952f9..97def6f781 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -138,7 +138,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -188,11 +189,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -283,7 +285,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -386,7 +389,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -434,7 +437,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -487,8 +491,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -541,7 +545,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 1725ad0736..b013da9631 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -507,9 +506,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -531,7 +529,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 76f94fa61f..33d952f9fd 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -579,10 +579,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -811,9 +808,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -841,7 +840,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1013,9 +1012,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1178,9 +1176,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 4be2eede92..7344a7c692 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -63,20 +57,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -114,19 +110,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -161,7 +157,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -177,11 +172,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -191,7 +182,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -238,10 +235,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -274,14 +272,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -294,7 +292,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -308,7 +306,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -350,7 +348,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index da929bf4cd..9329a6a6d6 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1037,16 +1043,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1070,7 +1074,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index f8f6a6264c..38f9e59f99 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index 705dc69c06..fdc41fff91 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -339,7 +339,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index 45abc444b7..93f9769ab4 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -100,14 +105,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Tue_Sep__8_16_35_16_2020_701)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v16-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v15 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 648 insertions(+), 487 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 9b2e59bf0e..b0d60a0d0f 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e570e56a24..f9b0108602 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -831,13 +831,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -912,8 +905,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1225,8 +1218,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4326,15 +4318,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4342,8 +4329,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6320,7 +6315,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6480,13 +6474,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11860,12 +11850,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11908,8 +11899,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12014,6 +12005,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3d599325ee..9281b57379 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -746,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -978,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1015,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1069,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1090,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1105,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1136,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 61902be3b0..a15b0b3355 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 88033a79b2..8a678074d5 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -486,9 +485,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -513,7 +511,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index bf2711bddd..2fd24a9b14 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -812,9 +809,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -842,7 +841,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1014,9 +1013,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1179,9 +1177,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2761,7 +2758,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2859,7 +2856,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 0b7e73ae79..3dd6df4be6 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6c8848e14f..6a7fe140cb 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -272,12 +249,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -297,6 +279,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Thu_Jul__2_13_53_30_2020_072)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v15 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 648 insertions(+), 487 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 9b2e59bf0e..b0d60a0d0f 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e570e56a24..f9b0108602 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -831,13 +831,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -912,8 +905,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1225,8 +1218,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4326,15 +4318,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4342,8 +4329,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6320,7 +6315,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6480,13 +6474,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11860,12 +11850,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11908,8 +11899,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12014,6 +12005,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3d599325ee..9281b57379 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -746,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -978,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1015,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1069,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1090,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1105,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1136,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 61902be3b0..a15b0b3355 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 88033a79b2..8a678074d5 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -486,9 +485,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -513,7 +511,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index bf2711bddd..2fd24a9b14 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -812,9 +809,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -842,7 +841,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1014,9 +1013,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1179,9 +1177,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2761,7 +2758,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2859,7 +2856,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 0b7e73ae79..3dd6df4be6 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6c8848e14f..6a7fe140cb 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -272,12 +249,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -297,6 +279,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Thu_Jul__2_13_53_30_2020_072)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v15 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 648 insertions(+), 487 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 9b2e59bf0e..b0d60a0d0f 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e570e56a24..f9b0108602 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -831,13 +831,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -912,8 +905,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1225,8 +1218,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4326,15 +4318,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4342,8 +4329,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6320,7 +6315,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6480,13 +6474,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11860,12 +11850,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11908,8 +11899,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12014,6 +12005,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3d599325ee..9281b57379 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -746,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -978,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1015,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1069,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1090,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1105,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1136,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 61902be3b0..a15b0b3355 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 88033a79b2..8a678074d5 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -486,9 +485,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -513,7 +511,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index bf2711bddd..2fd24a9b14 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -812,9 +809,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -842,7 +841,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1014,9 +1013,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1179,9 +1177,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2761,7 +2758,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2859,7 +2856,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 0b7e73ae79..3dd6df4be6 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6c8848e14f..6a7fe140cb 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -272,12 +249,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -297,6 +279,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Thu_Jul__2_13_53_30_2020_072)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v15 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 648 insertions(+), 487 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 9b2e59bf0e..b0d60a0d0f 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e570e56a24..f9b0108602 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -831,13 +831,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -912,8 +905,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1225,8 +1218,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4326,15 +4318,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4342,8 +4329,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6320,7 +6315,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6480,13 +6474,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11860,12 +11850,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11908,8 +11899,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12014,6 +12005,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3d599325ee..9281b57379 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -746,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -978,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1015,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1069,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1090,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1105,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1136,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 61902be3b0..a15b0b3355 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 88033a79b2..8a678074d5 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -486,9 +485,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -513,7 +511,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index bf2711bddd..2fd24a9b14 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -812,9 +809,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -842,7 +841,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1014,9 +1013,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1179,9 +1177,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2761,7 +2758,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2859,7 +2856,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 0b7e73ae79..3dd6df4be6 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6c8848e14f..6a7fe140cb 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -272,12 +249,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -297,6 +279,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Thu_Jul__2_13_53_30_2020_072)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v15 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 648 insertions(+), 487 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 9b2e59bf0e..b0d60a0d0f 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e570e56a24..f9b0108602 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -831,13 +831,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -912,8 +905,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1225,8 +1218,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4326,15 +4318,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4342,8 +4329,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6320,7 +6315,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6480,13 +6474,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11860,12 +11850,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11908,8 +11899,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12014,6 +12005,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3d599325ee..9281b57379 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -746,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -978,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1015,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1069,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1090,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1105,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1136,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 61902be3b0..a15b0b3355 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 88033a79b2..8a678074d5 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -486,9 +485,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -513,7 +511,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index bf2711bddd..2fd24a9b14 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -812,9 +809,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -842,7 +841,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1014,9 +1013,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1179,9 +1177,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2761,7 +2758,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2859,7 +2856,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 0b7e73ae79..3dd6df4be6 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6c8848e14f..6a7fe140cb 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -272,12 +249,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -297,6 +279,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Thu_Jul__2_13_53_30_2020_072)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v15 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 648 insertions(+), 487 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 9b2e59bf0e..b0d60a0d0f 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e570e56a24..f9b0108602 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -831,13 +831,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -912,8 +905,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1225,8 +1218,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4326,15 +4318,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4342,8 +4329,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6320,7 +6315,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6480,13 +6474,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11860,12 +11850,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11908,8 +11899,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12014,6 +12005,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3d599325ee..9281b57379 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -746,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -978,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1015,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1069,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1090,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1105,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1136,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 61902be3b0..a15b0b3355 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 88033a79b2..8a678074d5 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -486,9 +485,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -513,7 +511,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index bf2711bddd..2fd24a9b14 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -812,9 +809,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -842,7 +841,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1014,9 +1013,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1179,9 +1177,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2761,7 +2758,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2859,7 +2856,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 0b7e73ae79..3dd6df4be6 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6c8848e14f..6a7fe140cb 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -272,12 +249,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -297,6 +279,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Thu_Jul__2_13_53_30_2020_072)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v15 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 648 insertions(+), 487 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 9b2e59bf0e..b0d60a0d0f 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e570e56a24..f9b0108602 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -831,13 +831,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -912,8 +905,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1225,8 +1218,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4326,15 +4318,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4342,8 +4329,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6320,7 +6315,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6480,13 +6474,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11860,12 +11850,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11908,8 +11899,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12014,6 +12005,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3d599325ee..9281b57379 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -746,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -978,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1015,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1069,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1090,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1105,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1136,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 61902be3b0..a15b0b3355 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 88033a79b2..8a678074d5 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -486,9 +485,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -513,7 +511,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index bf2711bddd..2fd24a9b14 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -812,9 +809,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -842,7 +841,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1014,9 +1013,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1179,9 +1177,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2761,7 +2758,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2859,7 +2856,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 0b7e73ae79..3dd6df4be6 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6c8848e14f..6a7fe140cb 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -272,12 +249,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -297,6 +279,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Thu_Jul__2_13_53_30_2020_072)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v15 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 648 insertions(+), 487 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 9b2e59bf0e..b0d60a0d0f 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e570e56a24..f9b0108602 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -831,13 +831,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -912,8 +905,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1225,8 +1218,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4326,15 +4318,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4342,8 +4329,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6320,7 +6315,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6480,13 +6474,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11860,12 +11850,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11908,8 +11899,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12014,6 +12005,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3d599325ee..9281b57379 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -746,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -978,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1015,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1069,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1090,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1105,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1136,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 61902be3b0..a15b0b3355 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 88033a79b2..8a678074d5 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -486,9 +485,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -513,7 +511,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index bf2711bddd..2fd24a9b14 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -812,9 +809,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -842,7 +841,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1014,9 +1013,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1179,9 +1177,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2761,7 +2758,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2859,7 +2856,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 0b7e73ae79..3dd6df4be6 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6c8848e14f..6a7fe140cb 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -272,12 +249,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -297,6 +279,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Thu_Jul__2_13_53_30_2020_072)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v15 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 648 insertions(+), 487 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 9b2e59bf0e..b0d60a0d0f 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e570e56a24..f9b0108602 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -831,13 +831,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -912,8 +905,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1225,8 +1218,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4326,15 +4318,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4342,8 +4329,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6320,7 +6315,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6480,13 +6474,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11860,12 +11850,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11908,8 +11899,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12014,6 +12005,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3d599325ee..9281b57379 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -746,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -978,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1015,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1069,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1090,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1105,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1136,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 61902be3b0..a15b0b3355 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 88033a79b2..8a678074d5 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -486,9 +485,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -513,7 +511,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index bf2711bddd..2fd24a9b14 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -812,9 +809,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -842,7 +841,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1014,9 +1013,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1179,9 +1177,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2761,7 +2758,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2859,7 +2856,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 0b7e73ae79..3dd6df4be6 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6c8848e14f..6a7fe140cb 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -272,12 +249,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -297,6 +279,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Thu_Jul__2_13_53_30_2020_072)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v15 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 648 insertions(+), 487 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 9b2e59bf0e..b0d60a0d0f 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e570e56a24..f9b0108602 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -831,13 +831,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -912,8 +905,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1225,8 +1218,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4326,15 +4318,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4342,8 +4329,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6320,7 +6315,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6480,13 +6474,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11860,12 +11850,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11908,8 +11899,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12014,6 +12005,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3d599325ee..9281b57379 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -746,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -978,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1015,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1069,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1090,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1105,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1136,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 61902be3b0..a15b0b3355 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 88033a79b2..8a678074d5 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -486,9 +485,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -513,7 +511,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index bf2711bddd..2fd24a9b14 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -812,9 +809,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -842,7 +841,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1014,9 +1013,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1179,9 +1177,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2761,7 +2758,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2859,7 +2856,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 0b7e73ae79..3dd6df4be6 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6c8848e14f..6a7fe140cb 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -272,12 +249,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -297,6 +279,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Thu_Jul__2_13_53_30_2020_072)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v15 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 648 insertions(+), 487 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 9b2e59bf0e..b0d60a0d0f 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e570e56a24..f9b0108602 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -831,13 +831,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -912,8 +905,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1225,8 +1218,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4326,15 +4318,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4342,8 +4329,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6320,7 +6315,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6480,13 +6474,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11860,12 +11850,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11908,8 +11899,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12014,6 +12005,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3d599325ee..9281b57379 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -746,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -978,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1015,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1069,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1090,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1105,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1136,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 61902be3b0..a15b0b3355 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 88033a79b2..8a678074d5 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -486,9 +485,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -513,7 +511,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index bf2711bddd..2fd24a9b14 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -812,9 +809,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -842,7 +841,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1014,9 +1013,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1179,9 +1177,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2761,7 +2758,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2859,7 +2856,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 0b7e73ae79..3dd6df4be6 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6c8848e14f..6a7fe140cb 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -272,12 +249,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -297,6 +279,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Thu_Jul__2_13_53_30_2020_072)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v15 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 648 insertions(+), 487 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 9b2e59bf0e..b0d60a0d0f 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e570e56a24..f9b0108602 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -831,13 +831,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -912,8 +905,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1225,8 +1218,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4326,15 +4318,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4342,8 +4329,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6320,7 +6315,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6480,13 +6474,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11860,12 +11850,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11908,8 +11899,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12014,6 +12005,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3d599325ee..9281b57379 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -746,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -978,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1015,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1069,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1090,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1105,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1136,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 61902be3b0..a15b0b3355 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 88033a79b2..8a678074d5 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -486,9 +485,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -513,7 +511,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index bf2711bddd..2fd24a9b14 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -812,9 +809,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -842,7 +841,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1014,9 +1013,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1179,9 +1177,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2761,7 +2758,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2859,7 +2856,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 0b7e73ae79..3dd6df4be6 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6c8848e14f..6a7fe140cb 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -272,12 +249,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -297,6 +279,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Thu_Jul__2_13_53_30_2020_072)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v15 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 648 insertions(+), 487 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 9b2e59bf0e..b0d60a0d0f 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e570e56a24..f9b0108602 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -831,13 +831,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -912,8 +905,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1225,8 +1218,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4326,15 +4318,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4342,8 +4329,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6320,7 +6315,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6480,13 +6474,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11860,12 +11850,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11908,8 +11899,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12014,6 +12005,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3d599325ee..9281b57379 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -746,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -978,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1015,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1069,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1090,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1105,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1136,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 61902be3b0..a15b0b3355 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 88033a79b2..8a678074d5 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -486,9 +485,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -513,7 +511,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index bf2711bddd..2fd24a9b14 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -812,9 +809,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -842,7 +841,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1014,9 +1013,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1179,9 +1177,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2761,7 +2758,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2859,7 +2856,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 0b7e73ae79..3dd6df4be6 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6c8848e14f..6a7fe140cb 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -272,12 +249,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -297,6 +279,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Thu_Jul__2_13_53_30_2020_072)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v15 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 648 insertions(+), 487 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 9b2e59bf0e..b0d60a0d0f 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e570e56a24..f9b0108602 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -831,13 +831,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -912,8 +905,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1225,8 +1218,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4326,15 +4318,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4342,8 +4329,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6320,7 +6315,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6480,13 +6474,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11860,12 +11850,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11908,8 +11899,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12014,6 +12005,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3d599325ee..9281b57379 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -746,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -978,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1015,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1069,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1090,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1105,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1136,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 61902be3b0..a15b0b3355 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 88033a79b2..8a678074d5 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -486,9 +485,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -513,7 +511,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index bf2711bddd..2fd24a9b14 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -812,9 +809,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -842,7 +841,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1014,9 +1013,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1179,9 +1177,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2761,7 +2758,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2859,7 +2856,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 0b7e73ae79..3dd6df4be6 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6c8848e14f..6a7fe140cb 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -272,12 +249,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -297,6 +279,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Thu_Jul__2_13_53_30_2020_072)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v15 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 648 insertions(+), 487 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 9b2e59bf0e..b0d60a0d0f 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e570e56a24..f9b0108602 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -831,13 +831,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -912,8 +905,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1225,8 +1218,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4326,15 +4318,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4342,8 +4329,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6320,7 +6315,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6480,13 +6474,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11860,12 +11850,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11908,8 +11899,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12014,6 +12005,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3d599325ee..9281b57379 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -746,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -978,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1015,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1069,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1090,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1105,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1136,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 61902be3b0..a15b0b3355 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 88033a79b2..8a678074d5 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -486,9 +485,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -513,7 +511,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index bf2711bddd..2fd24a9b14 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -812,9 +809,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -842,7 +841,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1014,9 +1013,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1179,9 +1177,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2761,7 +2758,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2859,7 +2856,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 0b7e73ae79..3dd6df4be6 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6c8848e14f..6a7fe140cb 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -272,12 +249,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -297,6 +279,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Thu_Jul__2_13_53_30_2020_072)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v15 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 648 insertions(+), 487 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 9b2e59bf0e..b0d60a0d0f 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e570e56a24..f9b0108602 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -831,13 +831,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -912,8 +905,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1225,8 +1218,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4326,15 +4318,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4342,8 +4329,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6320,7 +6315,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6480,13 +6474,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11860,12 +11850,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11908,8 +11899,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12014,6 +12005,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3d599325ee..9281b57379 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -746,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -978,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1015,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1069,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1090,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1105,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1136,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 61902be3b0..a15b0b3355 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 88033a79b2..8a678074d5 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -486,9 +485,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -513,7 +511,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index bf2711bddd..2fd24a9b14 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -812,9 +809,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -842,7 +841,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1014,9 +1013,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1179,9 +1177,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2761,7 +2758,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2859,7 +2856,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 0b7e73ae79..3dd6df4be6 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6c8848e14f..6a7fe140cb 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -272,12 +249,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -297,6 +279,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Thu_Jul__2_13_53_30_2020_072)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v15 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 648 insertions(+), 487 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 9b2e59bf0e..b0d60a0d0f 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e570e56a24..f9b0108602 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -831,13 +831,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -912,8 +905,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1225,8 +1218,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4326,15 +4318,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4342,8 +4329,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6320,7 +6315,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6480,13 +6474,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11860,12 +11850,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11908,8 +11899,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12014,6 +12005,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3d599325ee..9281b57379 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -746,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -978,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1015,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1069,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1090,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1105,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1136,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 61902be3b0..a15b0b3355 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 88033a79b2..8a678074d5 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -486,9 +485,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -513,7 +511,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index bf2711bddd..2fd24a9b14 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -812,9 +809,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -842,7 +841,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1014,9 +1013,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1179,9 +1177,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2761,7 +2758,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2859,7 +2856,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 0b7e73ae79..3dd6df4be6 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6c8848e14f..6a7fe140cb 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -272,12 +249,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -297,6 +279,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Thu_Jul__2_13_53_30_2020_072)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v15 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 648 insertions(+), 487 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 9b2e59bf0e..b0d60a0d0f 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e570e56a24..f9b0108602 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -831,13 +831,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -912,8 +905,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1225,8 +1218,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4326,15 +4318,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4342,8 +4329,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6320,7 +6315,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6480,13 +6474,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11860,12 +11850,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11908,8 +11899,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12014,6 +12005,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3d599325ee..9281b57379 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -746,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -978,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1015,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1069,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1090,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1105,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1136,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 61902be3b0..a15b0b3355 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 88033a79b2..8a678074d5 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -486,9 +485,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -513,7 +511,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index bf2711bddd..2fd24a9b14 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -812,9 +809,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -842,7 +841,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1014,9 +1013,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1179,9 +1177,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2761,7 +2758,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2859,7 +2856,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 0b7e73ae79..3dd6df4be6 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6c8848e14f..6a7fe140cb 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -272,12 +249,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -297,6 +279,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Thu_Jul__2_13_53_30_2020_072)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v15 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 648 insertions(+), 487 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 9b2e59bf0e..b0d60a0d0f 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e570e56a24..f9b0108602 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -831,13 +831,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -912,8 +905,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1225,8 +1218,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4326,15 +4318,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4342,8 +4329,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6320,7 +6315,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6480,13 +6474,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11860,12 +11850,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11908,8 +11899,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12014,6 +12005,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3d599325ee..9281b57379 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -746,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -978,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1015,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1069,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1090,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1105,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1136,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 61902be3b0..a15b0b3355 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 88033a79b2..8a678074d5 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -486,9 +485,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -513,7 +511,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index bf2711bddd..2fd24a9b14 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -812,9 +809,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -842,7 +841,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1014,9 +1013,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1179,9 +1177,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2761,7 +2758,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2859,7 +2856,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 0b7e73ae79..3dd6df4be6 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6c8848e14f..6a7fe140cb 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -272,12 +249,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -297,6 +279,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Thu_Jul__2_13_53_30_2020_072)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v10 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 47 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 656 insertions(+), 494 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index e1904877fa..8630ad2032 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index da468598e4..840218efee 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -828,13 +828,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -909,8 +902,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1222,8 +1215,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4323,15 +4315,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4339,8 +4326,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6317,7 +6312,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6477,13 +6471,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11854,12 +11844,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11902,8 +11893,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12008,6 +11999,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 399bad0603..bdde75086c 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -71,7 +71,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -82,7 +82,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -105,8 +105,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -138,8 +136,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -244,6 +242,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -252,317 +251,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -570,7 +704,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -722,11 +857,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -744,7 +880,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -976,11 +1112,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1013,9 +1152,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1067,8 +1204,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1088,9 +1233,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1103,6 +1248,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1134,10 +1280,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc69e5ce5f..d99474c173 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 6fed3cfd23..cac197045d 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -465,9 +464,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -492,7 +490,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index d3a94d611f..cc7e7fdac7 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -293,11 +293,9 @@ InitWalSender(void) if (!am_db_walsender) { xlogreader = &fake_xlogreader; - xlogreader->routine = - *XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close); WALOpenSegmentInit(&xlogreader->seg, &xlogreader->segcxt, wal_segment_size, NULL); + xlogreader->cleanup_cb = wal_segment_close; } } @@ -816,9 +814,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -846,11 +846,11 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, - state->seg.ws_tli, /* Pass the current TLI because only + xlogreader->seg.ws_tli, /* Pass the current TLI because only * WalSndSegmentOpen controls whether new * TLI is needed. */ &errinfo)) @@ -863,8 +863,8 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req * read() succeeds in that case, but the data we tried to read might * already have been overwritten with new WAL records. */ - XLByteToSeg(targetPagePtr, segno, state->segcxt.ws_segsize); - CheckXLogRemoved(segno, state->seg.ws_tli); + XLByteToSeg(targetPagePtr, segno, xlogreader->segcxt.ws_segsize); + CheckXLogRemoved(segno, xlogreader->seg.ws_tli); state->readLen = count; return true; @@ -1018,9 +1018,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1183,9 +1182,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2495,14 +2493,14 @@ WalSndSegmentOpen(XLogReaderState *state, XLogSegNo nextSegNo, { XLogSegNo endSegNo; - XLByteToSeg(sendTimeLineValidUpto, endSegNo, state->segcxt.ws_segsize); - if (state->seg.ws_segno == endSegNo) + XLByteToSeg(sendTimeLineValidUpto, endSegNo, xlogreader->segcxt.ws_segsize); + if (xlogreader->seg.ws_segno == endSegNo) *tli_p = sendTimeLineNextTLI; } - XLogFilePath(path, *tli_p, nextSegNo, state->segcxt.ws_segsize); - state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); - if (state->seg.ws_file >= 0) + XLogFilePath(path, *tli_p, nextSegNo, xlogreader->segcxt.ws_segsize); + xlogreader->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); + if (xlogreader->seg.ws_file >= 0) return; /* @@ -2763,7 +2761,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2861,7 +2859,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 907db33b9e..cad8e13965 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 53e4212ac4..1d0167e26d 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -276,12 +253,17 @@ extern void WALOpenSegmentInit(WALOpenSegment *seg, WALSegmentContext *segcxt, /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -301,6 +283,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.2 ----Next_Part(Tue_May_26_16_40_02_2020_373)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v10-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v15 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 700 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 +-- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/replication/logical.h | 11 +- 13 files changed, 648 insertions(+), 487 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 9b2e59bf0e..b0d60a0d0f 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index e570e56a24..f9b0108602 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -831,13 +831,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -912,8 +905,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1225,8 +1218,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL NULL); if (!debug_reader) { @@ -4326,15 +4318,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4342,8 +4329,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6320,7 +6315,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool fast_promoted = false; struct stat st; @@ -6480,13 +6474,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11860,12 +11850,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -11908,8 +11899,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12014,6 +12005,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 3d599325ee..9281b57379 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,452 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - (uint32) (RecPtr >> 32), (uint32) RecPtr, - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - (uint32) (RecPtr >> 32), (uint32) RecPtr); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u at %X/%X", - pageHeader->xlp_rem_len, - (uint32) (RecPtr >> 32), (uint32) RecPtr); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +706,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +859,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -746,7 +882,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, (uint32) RecPtr); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -978,11 +1114,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1015,9 +1154,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1069,8 +1206,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1090,9 +1235,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1105,6 +1250,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1136,10 +1282,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 1b10b6df20..303333571f 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -689,8 +689,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -705,7 +704,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -792,6 +791,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -829,9 +829,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -944,11 +946,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 61902be3b0..a15b0b3355 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -120,7 +120,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -169,11 +170,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -231,7 +233,8 @@ CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -328,7 +331,7 @@ CreateInitDecodingContext(char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -376,7 +379,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -429,8 +433,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -483,7 +487,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index b99c94e848..fcc81b358e 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 88033a79b2..8a678074d5 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -152,9 +152,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -486,9 +485,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -513,7 +511,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index bf2711bddd..2fd24a9b14 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -812,9 +809,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -842,7 +841,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1014,9 +1013,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1179,9 +1177,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2761,7 +2758,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2859,7 +2856,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 0b7e73ae79..3dd6df4be6 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -40,15 +40,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -62,20 +56,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -113,19 +109,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -160,7 +156,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -176,11 +171,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -190,7 +181,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -237,10 +234,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -273,14 +271,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -293,7 +291,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -307,7 +305,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -349,7 +347,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index ab0c28d9b7..02e71138cc 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1042,16 +1048,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1075,7 +1079,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 6c8848e14f..6a7fe140cb 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -227,8 +199,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -255,6 +225,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -262,9 +241,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -272,12 +249,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -297,6 +279,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index c287edf206..482e4ced69 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c2f2475e5d..a743db49cf 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -95,14 +100,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.18.4 ----Next_Part(Thu_Jul__2_13_53_30_2020_072)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v17 2/4] Move page-reader out of XLogReadRecord @ 2019-09-10 03:58 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2019-09-10 03:58 UTC (permalink / raw) This is the second step of removing callbacks from WAL record reader. Since it is essential to take in additional data while reading a record, the function have to ask caller for new data while keeping working state. Thus the function is turned into a state machine. --- src/backend/access/transam/twophase.c | 15 +- src/backend/access/transam/xlog.c | 58 +- src/backend/access/transam/xlogreader.c | 697 +++++++++++------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 26 +- .../replication/logical/logicalfuncs.c | 13 +- src/backend/replication/slotfuncs.c | 18 +- src/backend/replication/walsender.c | 32 +- src/bin/pg_rewind/parsexlog.c | 84 ++- src/bin/pg_waldump/pg_waldump.c | 36 +- src/include/access/xlogreader.h | 121 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 646 insertions(+), 488 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 80d2d20d6c..7d5a96a5f5 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1325,11 +1325,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) XLogReaderState *xlogreader; char *errormsg; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1337,7 +1334,13 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + break; + } + if (record == NULL) ereport(ERROR, (errcode_for_file_access(), diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 606328a65a..670996ae67 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -917,8 +910,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static int emode_for_corrupt_record(int emode, XLogRecPtr RecPtr); @@ -1231,8 +1224,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4344,15 +4336,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4360,8 +4347,16 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + break; + + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6380,7 +6375,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6539,13 +6533,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -11987,12 +11977,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12035,8 +12026,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12141,6 +12132,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 7d04995b7b..ba3e4868f7 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -40,7 +40,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -73,7 +73,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -84,7 +84,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -107,8 +107,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -140,8 +138,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -246,6 +244,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -254,317 +253,449 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * - * The returned pointer (or *errormsg) points to an internal buffer that's - * valid until the next call to XLogReadRecord. + * Returns XLREAD_NEED_DATA if more data is needed to finish reading the + * current record. In that case, state->readPagePtr and state->readLen inform + * the desired position and minimum length of data needed. The caller shall + * read in the requested data and set state->readBuf to point to a buffer + * containing it. The caller must also set state->readPageTLI and + * state->readLen to indicate the timeline that it was read from, and the + * length of data that is now available (which must be >= given readLen), + * respectively. + * + * If invalid data is encountered, returns XLREAD_FAIL with *record being set to + * NULL. *errormsg is set to a string with details of the failure. + * The returned pointer (or *errormsg) points to an internal buffer that's valid + * until the next call to XLogReadRecord. + * + * + * This function runs a state machine consists of the following states. + * + * XLREAD_NEXT_RECORD : + * The initial state, if called with valid RecPtr, try to read a record at + * that position. If invalid RecPtr is given try to read a record just after + * the last one previously read. + * This state ens after setting ReadRecPtr. Then goes to XLREAD_TOT_LEN. + * + * XLREAD_TOT_LEN: + * Examining record header. Ends after reading record total + * length. recordRemainLen and recordGotLen are initialized. + * + * XLREAD_FIRST_FRAGMENT: + * Reading the first fragment. Ends with finishing reading a single + * record. Goes to XLREAD_NEXT_RECORD if that's all or + * XLREAD_CONTINUATION if we have continuation. + + * XLREAD_CONTINUATION: + * Reading continuation of record. Ends with finishing the whole record then + * goes to XLREAD_NEXT_RECORD. During this state, recordRemainLen indicates + * how much is left and readRecordBuf holds the partially assert + * record.recordContRecPtr points to the beginning of the next page where to + * continue. + * + * If wrong data found in any state, the state machine stays at the current + * state. This behavior allows to continue reading a reacord switching among + * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); - - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - - state->currRecPtr = RecPtr; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) - { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) + switch (state->readRecordState) { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) - break; + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the header + * size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else + { + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ } + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the page, + * the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ if (!state->page_verified) goto err; - Assert(SizeOfXLogShortPHD <= state->readLen); + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - /* Check that the continuation on next page looks valid */ pageHeader = (XLogPageHeader) state->readBuf; - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); goto err; } - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) - { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); - + /* XLogNeedData has verified the page header */ Assert(pageHeaderSize <= state->readLen); - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the whole + * record header might not fit on this page. xl_tot_len is the first + * field of the struct, so it must be on this page (the records are + * MAXALIGNed), but we cannot access any other fields until we've + * verified that we got the whole header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; - Assert (pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after reading it + * from the next page. The xl_tot_len check is necessary here to + * ensure that we enter the XLREAD_CONTINUATION state below; + * otherwise we might fail to apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) + state->record_verified = true; + } + else { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); goto err; - gotheader = true; + } } - } while (gotlen < total_len); - - Assert(gotheader); - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Wait for the rest of the record, or the part of the record that + * fit on the first page if crossed a page boundary, to become + * available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) + case XLREAD_FIRST_FRAGMENT: { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert (targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; + } + + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); + + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); + + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ + + case XLREAD_CONTINUATION: + { + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + + /* we enter this state only if we haven't read the whole record. */ + Assert (state->recordRemainLen > 0); + + while(state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; + + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; + + /* this request contains page header */ + Assert (targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; + + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); - if (!state->page_verified) - goto err; + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; + /* + * Cross-check that xlp_rem_len agrees with how much of the + * record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } - state->EndRecPtr = RecPtr + MAXALIGN(total_len); + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); - state->ReadRecPtr = RecPtr; + /* + * XLogNeedData should have ensured that the whole page header + * was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* XLogNeedData should have ensured all needed data was read */ + Assert (state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* Calculate pointer to beginning of next page, and continue */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; + break; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert (!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); @@ -572,7 +703,8 @@ err: if (state->errormsg_buf[0] != '\0') *errormsg = state->errormsg_buf; - return NULL; + *record = NULL; + return XLREAD_FAIL; } /* @@ -724,11 +856,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -745,7 +878,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -975,11 +1108,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1012,9 +1148,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while(XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1066,8 +1200,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1087,9 +1229,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1102,6 +1244,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1133,10 +1276,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 46eda33f25..b003990745 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -686,8 +686,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -702,7 +701,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -788,6 +787,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -825,9 +825,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -940,11 +942,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 37b75deb72..9cbd8afa49 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -476,7 +479,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -528,8 +532,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -585,7 +589,13 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index f7e055874e..b69f6911c5 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -233,9 +233,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -284,7 +283,13 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9817b44113..deb7cf15eb 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -153,9 +153,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -512,9 +511,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -536,7 +534,13 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + break; + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index c36b91ae5e..062093727d 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -580,10 +580,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -807,9 +804,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -837,7 +836,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1011,9 +1010,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1171,9 +1169,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2749,7 +2746,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2847,7 +2844,12 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + break; + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..712c85281c 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,22 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -123,19 +119,19 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + break; + } if (record == NULL) { if (errormsg) @@ -170,7 +166,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +181,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +191,13 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + break; + } if (record == NULL) { @@ -247,10 +244,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +281,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +301,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +315,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +357,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 0f0e0723a3..f514de6b13 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -330,12 +330,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -353,8 +358,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -374,6 +379,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, (Size) errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1035,16 +1041,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1067,7 +1071,13 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + break; + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 23d9e70a59..4e9268b553 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,35 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState { + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +136,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* ---------------------------------------- * Communication with page reader @@ -187,7 +157,9 @@ struct XLogReaderState * the request, or -1 on error */ TimeLineID readPageTLI; /* TLI for data currently in readBuf */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified;/* is the current record header verified? */ + /* ---------------------------------------- @@ -229,8 +201,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -257,6 +227,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState;/* state machine state */ + int recordGotLen; /* amount of current record that has + * already been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -264,9 +243,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -274,12 +251,17 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -299,6 +281,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 364a21c4ea..397fb27fc2 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -47,9 +47,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index f10ad0acd6..94749609b4 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -377,7 +377,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index c253403372..b936f31393 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -105,14 +110,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Mar__4_11_28_53_2021_014)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v17-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* [PATCH v18 2/5] Move page-reader out of XLogReadRecord(). @ 2021-09-30 03:04 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Kyotaro Horiguchi @ 2021-09-30 03:04 UTC (permalink / raw) This is the second step of removing callbacks from the WAL decoder. XLogReadRecord() return XLREAD_NEED_DATA to indicate that the caller should supply new data, and the decoder works as a state machine. Author: Kyotaro HORIGUCHI <[email protected]> Author: Heikki Linnakangas <[email protected]> Reviewed-by: Antonin Houska <[email protected]> Reviewed-by: Alvaro Herrera <[email protected]> Reviewed-by: Takashi Menjo <[email protected]> Reviewed-by: Thomas Munro <[email protected]> Discussion: https://postgr.es/m/20190418.210257.43726183.horiguchi.kyotaro%40lab.ntt.co.jp --- src/backend/access/transam/twophase.c | 16 +- src/backend/access/transam/xlog.c | 60 +- src/backend/access/transam/xlogreader.c | 760 ++++++++++-------- src/backend/access/transam/xlogutils.c | 17 +- src/backend/replication/logical/logical.c | 29 +- .../replication/logical/logicalfuncs.c | 16 +- src/backend/replication/slotfuncs.c | 21 +- src/backend/replication/walsender.c | 35 +- src/bin/pg_rewind/parsexlog.c | 93 ++- src/bin/pg_waldump/pg_waldump.c | 39 +- src/include/access/xlogreader.h | 124 ++- src/include/access/xlogutils.h | 4 +- src/include/pg_config_manual.h | 2 +- src/include/replication/logical.h | 11 +- 14 files changed, 703 insertions(+), 524 deletions(-) diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 2156de187c..9b42a935a7 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1330,11 +1330,8 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) char *errormsg; TimeLineID save_currtli = ThisTimeLineID; - xlogreader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &read_local_xlog_page, - .segment_open = &wal_segment_open, - .segment_close = &wal_segment_close), - NULL); + xlogreader = XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -1342,7 +1339,14 @@ XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len) errdetail("Failed while allocating a WAL reading processor."))); XLogBeginRead(xlogreader, lsn); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == XLREAD_NEED_DATA) + { + if (!read_local_xlog_page(xlogreader)) + { + XLogTerminateRead(xlogreader); + break; + } + } /* * Restore immediately the timeline where it was previously, as diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 1557ceb8c1..316ba256f6 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -836,13 +836,6 @@ static XLogSource currentSource = XLOG_FROM_ANY; static bool lastSourceFailed = false; static bool pendingWalRcvRestart = false; -typedef struct XLogPageReadPrivate -{ - int emode; - bool fetching_ckpt; /* are we fetching a checkpoint record? */ - bool randAccess; -} XLogPageReadPrivate; - /* * These variables track when we last obtained some WAL data to process, * and where we got it from. (XLogReceiptSource is initially the same as @@ -918,8 +911,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, static int XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli, XLogSource source, bool notfoundOk); static int XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source); -static bool XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess); static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, bool fetching_ckpt, XLogRecPtr tliRecPtr); static void XLogShutdownWalRcv(void); @@ -1233,8 +1226,7 @@ XLogInsertRecord(XLogRecData *rdata, appendBinaryStringInfo(&recordBuf, rdata->data, rdata->len); if (!debug_reader) - debug_reader = XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(), NULL); + debug_reader = XLogReaderAllocate(wal_segment_size, NULL, NULL); if (!debug_reader) { @@ -4395,15 +4387,10 @@ CleanupBackupHistory(void) * record is available. */ static XLogRecord * -ReadRecord(XLogReaderState *xlogreader, int emode, - bool fetching_ckpt) +ReadRecord(XLogReaderState *xlogreader, int emode, bool fetching_ckpt) { XLogRecord *record; - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; - - private->fetching_ckpt = fetching_ckpt; - private->emode = emode; - private->randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); + bool randAccess = (xlogreader->ReadRecPtr == InvalidXLogRecPtr); /* This is the first attempt to read this page. */ lastSourceFailed = false; @@ -4411,8 +4398,18 @@ ReadRecord(XLogReaderState *xlogreader, int emode, for (;;) { char *errormsg; + XLogReadRecordResult result; + + while ((result = XLogReadRecord(xlogreader, &record, &errormsg)) + == XLREAD_NEED_DATA) + { + if (!XLogPageRead(xlogreader, fetching_ckpt, emode, randAccess)) + { + XLogTerminateRead(xlogreader); + break; + } + } - record = XLogReadRecord(xlogreader, &errormsg); ReadRecPtr = xlogreader->ReadRecPtr; EndRecPtr = xlogreader->EndRecPtr; if (record == NULL) @@ -6547,7 +6544,6 @@ StartupXLOG(void) bool backupFromStandby = false; DBState dbstate_at_startup; XLogReaderState *xlogreader; - XLogPageReadPrivate private; bool promoted = false; struct stat st; @@ -6706,13 +6702,9 @@ StartupXLOG(void) OwnLatch(&XLogCtl->recoveryWakeupLatch); /* Set up XLOG reader facility */ - MemSet(&private, 0, sizeof(XLogPageReadPrivate)); xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.page_read = &XLogPageRead, - .segment_open = NULL, - .segment_close = wal_segment_close), - &private); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); + if (!xlogreader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -12300,12 +12292,13 @@ CancelBackup(void) * sleep and retry. */ static bool -XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *readBuf) +XLogPageRead(XLogReaderState *xlogreader, + bool fetching_ckpt, int emode, bool randAccess) { - XLogPageReadPrivate *private = - (XLogPageReadPrivate *) xlogreader->private_data; - int emode = private->emode; + char *readBuf = xlogreader->readBuf; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + int reqLen = xlogreader->readLen; + XLogRecPtr targetRecPtr = xlogreader->ReadRecPtr; uint32 targetPageOff; XLogSegNo targetSegNo PG_USED_FOR_ASSERTS_ONLY; int r; @@ -12348,8 +12341,8 @@ retry: flushedUpto < targetPagePtr + reqLen)) { if (!WaitForWALToBecomeAvailable(targetPagePtr + reqLen, - private->randAccess, - private->fetching_ckpt, + randAccess, + fetching_ckpt, targetRecPtr)) { if (readFile >= 0) @@ -12469,6 +12462,7 @@ retry: goto next_record_is_invalid; } + Assert(xlogreader->readPagePtr == targetPagePtr); xlogreader->readLen = readLen; return true; diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 1d9976ecf4..4501a09245 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -43,7 +43,7 @@ static bool XLogNeedData(XLogReaderState *state, XLogRecPtr pageptr, int reqLen, bool header_inclusive); static void XLogReaderInvalReadState(XLogReaderState *state); static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess); + XLogRecPtr PrevRecPtr, XLogRecord *record); static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr); static void ResetDecoder(XLogReaderState *state); @@ -76,7 +76,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...) */ XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, void *private_data) + WALSegmentCleanupCB cleanup_cb) { XLogReaderState *state; @@ -87,7 +87,7 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, return NULL; /* initialize caller-provided support functions */ - state->routine = *routine; + state->cleanup_cb = cleanup_cb; state->max_block_id = -1; @@ -110,8 +110,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir, WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size, waldir); - /* system_identifier initialized to zeroes above */ - state->private_data = private_data; /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1, MCXT_ALLOC_NO_OOM); @@ -143,8 +141,8 @@ XLogReaderFree(XLogReaderState *state) { int block_id; - if (state->seg.ws_file != -1) - state->routine.segment_close(state); + if (state->seg.ws_file >= 0) + state->cleanup_cb(state); for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++) { @@ -249,6 +247,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) /* Begin at the passed-in record pointer. */ state->EndRecPtr = RecPtr; state->ReadRecPtr = InvalidXLogRecPtr; + state->readRecordState = XLREAD_NEXT_RECORD; } /* @@ -257,12 +256,12 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * XLogBeginRead() or XLogFindNextRecord() must be called before the first call * to XLogReadRecord(). * - * If the page_read callback fails to read the requested data, NULL is - * returned. The callback is expected to have reported the error; errormsg - * is set to NULL. + * This function may return XLREAD_NEED_DATA several times before returning a + * result record. The caller shall read in some new data then call this + * function again with the same parameters. * - * If the reading fails for some other reason, NULL is also returned, and - * *errormsg is set to a string with details of the failure. + * When a record is successfully read, returns XLREAD_SUCCESS with result + * record being stored in *record. Otherwise *record is NULL. * * Returns XLREAD_NEED_DATA if more data is needed to finish reading the * current record. In that case, state->readPagePtr and state->readLen inform @@ -307,329 +306,458 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr) * state. This behavior allows to continue reading a reacord switching among * different souces, while streaming replication. */ -XLogRecord * -XLogReadRecord(XLogReaderState *state, char **errormsg) +XLogReadRecordResult +XLogReadRecord(XLogReaderState *state, XLogRecord **record, char **errormsg) { - XLogRecPtr RecPtr; - XLogRecord *record; - XLogRecPtr targetPagePtr; - bool randAccess; - uint32 len, - total_len; - uint32 targetRecOff; - uint32 pageHeaderSize; - bool assembled; - bool gotheader; + XLogRecord *prec; - /* - * randAccess indicates whether to verify the previous-record pointer of - * the record we're reading. We only do this if we're reading - * sequentially, which is what we initially assume. - */ - randAccess = false; + *record = NULL; /* reset error state */ *errormsg = NULL; state->errormsg_buf[0] = '\0'; - ResetDecoder(state); state->abortedRecPtr = InvalidXLogRecPtr; state->missingContrecPtr = InvalidXLogRecPtr; - RecPtr = state->EndRecPtr; - - if (state->ReadRecPtr != InvalidXLogRecPtr) - { - /* read the record after the one we just read */ - - /* - * EndRecPtr is pointing to end+1 of the previous WAL record. If - * we're at a page boundary, no more records can fit on the current - * page. We must skip over the page header, but we can't do that until - * we've read in the page, since the header size is variable. - */ - } - else - { - /* - * Caller supplied a position to start at. - * - * In this case, EndRecPtr should already be pointing to a valid - * record starting position. - */ - Assert(XRecOffIsValid(RecPtr)); - randAccess = true; - } - restart: - state->currRecPtr = RecPtr; - assembled = false; - - targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ); - targetRecOff = RecPtr % XLOG_BLCKSZ; - - /* - * Read the page containing the record into state->readBuf. Request enough - * byte to cover the whole record header, or at least the part of it that - * fits on the same page. - */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), - targetRecOff != 0)) + switch (state->readRecordState) { - if (!state->routine.page_read(state, state->readPagePtr, state->readLen, - RecPtr, state->readBuf)) - break; - } - - if (!state->page_verified) - goto err; - - /* - * We have at least the page header, so we can examine it now. - */ - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - if (targetRecOff == 0) - { - /* - * At page start, so skip over page header. - */ - RecPtr += pageHeaderSize; - targetRecOff = pageHeaderSize; - } - else if (targetRecOff < pageHeaderSize) - { - report_invalid_record(state, "invalid record offset at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + case XLREAD_NEXT_RECORD: + ResetDecoder(state); - if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) && - targetRecOff == pageHeaderSize) - { - report_invalid_record(state, "contrecord is requested by %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* XLogNeedData has verified the page header */ - Assert(pageHeaderSize <= state->readLen); - - /* - * Read the record length. - * - * NB: Even though we use an XLogRecord pointer here, the whole record - * header might not fit on this page. xl_tot_len is the first field of the - * struct, so it must be on this page (the records are MAXALIGNed), but we - * cannot access any other fields until we've verified that we got the - * whole header. - */ - record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ); - total_len = record->xl_tot_len; - - /* - * If the whole record header is on this page, validate it immediately. - * Otherwise do just a basic sanity check on xl_tot_len, and validate the - * rest of the header after reading it from the next page. The xl_tot_len - * check is necessary here to ensure that we enter the "Need to reassemble - * record" code path below; otherwise we might fail to apply - * ValidXLogRecordHeader at all. - */ - if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) - { - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record, - randAccess)) - goto err; - gotheader = true; - } - else - { - /* XXX: more validation should be done here */ - if (total_len < SizeOfXLogRecord) - { - report_invalid_record(state, - "invalid record length at %X/%X: wanted %u, got %u", - LSN_FORMAT_ARGS(RecPtr), - (uint32) SizeOfXLogRecord, total_len); - goto err; - } - gotheader = false; - } - - len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ; - if (total_len > len) - { - /* Need to reassemble record */ - char *contdata; - XLogPageHeader pageHeader; - char *buffer; - uint32 gotlen; - - assembled = true; - - /* - * Enlarge readRecordBuf as needed. - */ - if (total_len > state->readRecordBufSize && - !allocate_recordbuf(state, total_len)) - { - /* We treat this as a "bogus data" condition */ - report_invalid_record(state, "record length %u at %X/%X too long", - total_len, LSN_FORMAT_ARGS(RecPtr)); - goto err; - } - - /* Copy the first fragment of the record from the first page. */ - memcpy(state->readRecordBuf, - state->readBuf + RecPtr % XLOG_BLCKSZ, len); - buffer = state->readRecordBuf + len; - gotlen = len; - - do - { - int rest_len = total_len - gotlen; - - /* Calculate pointer to beginning of next page */ - targetPagePtr += XLOG_BLCKSZ; - - /* Wait for the next page to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(rest_len, XLOG_BLCKSZ), - false)) + if (state->ReadRecPtr != InvalidXLogRecPtr) + { + /* read the record after the one we just read */ + + /* + * EndRecPtr is pointing to end+1 of the previous WAL record. + * If we're at a page boundary, no more records can fit on the + * current page. We must skip over the page header, but we + * can't do that until we've read in the page, since the + * header size is variable. + */ + state->PrevRecPtr = state->ReadRecPtr; + state->ReadRecPtr = state->EndRecPtr; + } + else { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, - state->readBuf)) + /* + * Caller supplied a position to start at. + * + * In this case, EndRecPtr should already be pointing to a + * valid record starting position. + */ + Assert(XRecOffIsValid(state->EndRecPtr)); + state->ReadRecPtr = state->EndRecPtr; + + /* + * We cannot verify the previous-record pointer when we're + * seeking to a particular record. Reset PrevRecPtr so that we + * won't try doing that. + */ + state->PrevRecPtr = InvalidXLogRecPtr; + state->EndRecPtr = InvalidXLogRecPtr; /* to be tidy */ + } + + state->record_verified = false; + state->readRecordState = XLREAD_TOT_LEN; + /* fall through */ + + case XLREAD_TOT_LEN: + { + uint32 total_len; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + XLogPageHeader pageHeader; + + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + /* + * Check if we have enough data. For the first record in the + * page, the requesting length doesn't contain page header. + */ + if (XLogNeedData(state, targetPagePtr, + Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ), + targetRecOff != 0)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + /* examine page header now. */ + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + if (targetRecOff == 0) + { + /* At page start, so skip over page header. */ + state->ReadRecPtr += pageHeaderSize; + targetRecOff = pageHeaderSize; + } + else if (targetRecOff < pageHeaderSize) + { + report_invalid_record(state, "invalid record offset at %X/%X", + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } + + pageHeader = (XLogPageHeader) state->readBuf; + if ((pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD) && + targetRecOff == pageHeaderSize) + { + report_invalid_record(state, "contrecord is requested by %X/%X", + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* XLogNeedData has verified the page header */ + Assert(pageHeaderSize <= state->readLen); + + /* + * Read the record length. + * + * NB: Even though we use an XLogRecord pointer here, the + * whole record header might not fit on this page. xl_tot_len + * is the first field of the struct, so it must be on this + * page (the records are MAXALIGNed), but we cannot access any + * other fields until we've verified that we got the whole + * header. + */ + prec = (XLogRecord *) (state->readBuf + + state->ReadRecPtr % XLOG_BLCKSZ); + total_len = prec->xl_tot_len; + + /* + * If the whole record header is on this page, validate it + * immediately. Otherwise do just a basic sanity check on + * xl_tot_len, and validate the rest of the header after + * reading it from the next page. The xl_tot_len check is + * necessary here to ensure that we enter the + * XLREAD_CONTINUATION state below; otherwise we might fail to + * apply ValidXLogRecordHeader at all. + */ + if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + else + { + /* XXX: more validation should be done here */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(state->ReadRecPtr), + (uint32) SizeOfXLogRecord, total_len); + goto err; + } + } + + /* + * Wait for the rest of the record, or the part of the record + * that fit on the first page if crossed a page boundary, to + * become available. + */ + state->recordGotLen = 0; + state->recordRemainLen = total_len; + state->readRecordState = XLREAD_FIRST_FRAGMENT; + } + /* fall through */ + + case XLREAD_FIRST_FRAGMENT: + { + uint32 total_len = state->recordRemainLen; + uint32 request_len; + uint32 record_len; + XLogRecPtr targetPagePtr; + uint32 targetRecOff; + + /* + * Wait for the rest of the record on the first page to become + * available + */ + targetPagePtr = + state->ReadRecPtr - (state->ReadRecPtr % XLOG_BLCKSZ); + targetRecOff = state->ReadRecPtr % XLOG_BLCKSZ; + + request_len = Min(targetRecOff + total_len, XLOG_BLCKSZ); + record_len = request_len - targetRecOff; + + /* ReadRecPtr contains page header */ + Assert(targetRecOff != 0); + if (XLogNeedData(state, targetPagePtr, request_len, true)) + return XLREAD_NEED_DATA; + + /* error out if caller supplied bogus page */ + if (!state->page_verified) + goto err; + + prec = (XLogRecord *) (state->readBuf + targetRecOff); + + /* validate record header if not yet */ + if (!state->record_verified && record_len >= SizeOfXLogRecord) + { + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, prec)) + goto err; + + state->record_verified = true; + } + + + if (total_len == record_len) + { + /* Record does not cross a page boundary */ + Assert(state->record_verified); + + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) + goto err; + + state->record_verified = true; /* to be tidy */ + + /* We already checked the header earlier */ + state->EndRecPtr = state->ReadRecPtr + MAXALIGN(record_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; - } + } - if (!state->page_verified) - goto err; + /* + * The record continues on the next page. Need to reassemble + * record + */ + Assert(total_len > record_len); - Assert(SizeOfXLogShortPHD <= state->readLen); + /* Enlarge readRecordBuf as needed. */ + if (total_len > state->readRecordBufSize && + !allocate_recordbuf(state, total_len)) + { + /* We treat this as a "bogus data" condition */ + report_invalid_record(state, + "record length %u at %X/%X too long", + total_len, + LSN_FORMAT_ARGS(state->ReadRecPtr)); + goto err; + } - pageHeader = (XLogPageHeader) state->readBuf; + /* Copy the first fragment of the record from the first page. */ + memcpy(state->readRecordBuf, state->readBuf + targetRecOff, + record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; - /* - * If we were expecting a continuation record and got an - * "overwrite contrecord" flag, that means the continuation record - * was overwritten with a different record. Restart the read by - * assuming the address to read is the location where we found - * this flag; but keep track of the LSN of the record we were - * reading, for later verification. - */ - if (pageHeader->xlp_info & XLP_FIRST_IS_OVERWRITE_CONTRECORD) - { - state->overwrittenRecPtr = state->currRecPtr; - ResetDecoder(state); - RecPtr = targetPagePtr; - goto restart; - } + /* Calculate pointer to beginning of next page */ + state->recordContRecPtr = state->ReadRecPtr + record_len; + Assert(state->recordContRecPtr % XLOG_BLCKSZ == 0); - /* Check that the continuation on next page looks valid */ - if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) - { - report_invalid_record(state, - "there is no contrecord flag at %X/%X", - LSN_FORMAT_ARGS(RecPtr)); - goto err; + state->readRecordState = XLREAD_CONTINUATION; } + /* fall through */ - /* - * Cross-check that xlp_rem_len agrees with how much of the record - * we expect there to be left. - */ - if (pageHeader->xlp_rem_len == 0 || - total_len != (pageHeader->xlp_rem_len + gotlen)) + case XLREAD_CONTINUATION: { - report_invalid_record(state, - "invalid contrecord length %u (expected %lld) at %X/%X", - pageHeader->xlp_rem_len, - ((long long) total_len) - gotlen, - LSN_FORMAT_ARGS(RecPtr)); - goto err; - } + XLogPageHeader pageHeader; + uint32 pageHeaderSize; + XLogRecPtr targetPagePtr; - /* Append the continuation from this page to the buffer */ - pageHeaderSize = XLogPageHeaderSize(pageHeader); + /* + * we enter this state only if we haven't read the whole + * record. + */ + Assert(state->recordRemainLen > 0); - Assert(pageHeaderSize <= state->readLen); + while (state->recordRemainLen > 0) + { + char *contdata; + uint32 request_len; + uint32 record_len; - contdata = (char *) state->readBuf + pageHeaderSize; - len = XLOG_BLCKSZ - pageHeaderSize; - if (pageHeader->xlp_rem_len < len) - len = pageHeader->xlp_rem_len; + /* Wait for the next page to become available */ + targetPagePtr = state->recordContRecPtr; - Assert(pageHeaderSize + len <= state->readLen); - memcpy(buffer, (char *) contdata, len); - buffer += len; - gotlen += len; + /* this request contains page header */ + Assert(targetPagePtr != 0); + if (XLogNeedData(state, targetPagePtr, + Min(state->recordRemainLen, XLOG_BLCKSZ), + false)) + return XLREAD_NEED_DATA; - /* If we just reassembled the record header, validate it. */ - if (!gotheader) - { - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, - record, randAccess)) + if (!state->page_verified) + goto err; + + Assert(SizeOfXLogShortPHD <= state->readLen); + + /* Check that the continuation on next page looks valid */ + pageHeader = (XLogPageHeader) state->readBuf; + + /* + * If we were expecting a continuation record and got an + * "overwrite contrecord" flag, that means the continuation + * record was overwritten with a different record. Restart + * the read by assuming the address to read is the location + * where we found this flag; but keep track of the LSN of + * the record we were reading, for later verification. + */ + if (pageHeader->xlp_info & + XLP_FIRST_IS_OVERWRITE_CONTRECORD) + { + state->overwrittenRecPtr = state->ReadRecPtr; + state->EndRecPtr = targetPagePtr; + state->readRecordState = XLREAD_NEXT_RECORD; + + /* + * ReadRecPtr is the PrevRecPtr of the next + * record. Keep the LSN at the retry. + */ + state->ReadRecPtr = state->PrevRecPtr; + + goto restart; + } + + if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD)) + { + report_invalid_record( + state, + "there is no contrecord flag at %X/%X reading %X/%X", + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr); + goto err; + } + + /* + * Cross-check that xlp_rem_len agrees with how much of + * the record we expect there to be left. + */ + if (pageHeader->xlp_rem_len == 0 || + pageHeader->xlp_rem_len != state->recordRemainLen) + { + report_invalid_record( + state, + "invalid contrecord length %u at %X/%X reading %X/%X, expected %u", + pageHeader->xlp_rem_len, + (uint32) (state->recordContRecPtr >> 32), + (uint32) state->recordContRecPtr, + (uint32) (state->ReadRecPtr >> 32), + (uint32) state->ReadRecPtr, + state->recordRemainLen); + goto err; + } + + /* Append the continuation from this page to the buffer */ + pageHeaderSize = XLogPageHeaderSize(pageHeader); + + /* + * XLogNeedData should have ensured that the whole page + * header was read + */ + Assert(state->readLen >= pageHeaderSize); + + contdata = (char *) state->readBuf + pageHeaderSize; + record_len = XLOG_BLCKSZ - pageHeaderSize; + if (pageHeader->xlp_rem_len < record_len) + record_len = pageHeader->xlp_rem_len; + + request_len = record_len + pageHeaderSize; + + /* + * XLogNeedData should have ensured all needed data was + * read + */ + Assert(state->readLen >= request_len); + + memcpy(state->readRecordBuf + state->recordGotLen, + (char *) contdata, record_len); + state->recordGotLen += record_len; + state->recordRemainLen -= record_len; + + /* If we just reassembled the record header, validate it. */ + if (!state->record_verified) + { + Assert(state->recordGotLen >= SizeOfXLogRecord); + if (!ValidXLogRecordHeader(state, state->ReadRecPtr, + state->PrevRecPtr, + (XLogRecord *) state->readRecordBuf)) + goto err; + + state->record_verified = true; + } + + /* + * Calculate pointer to beginning of next page, and + * continue + */ + state->recordContRecPtr += XLOG_BLCKSZ; + } + + /* targetPagePtr is pointing the last-read page here */ + prec = (XLogRecord *) state->readRecordBuf; + if (!ValidXLogRecord(state, prec, state->ReadRecPtr)) goto err; - gotheader = true; - } - } while (gotlen < total_len); - - Assert(gotheader); - - record = (XLogRecord *) state->readRecordBuf; - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; - - pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf); - state->ReadRecPtr = RecPtr; - state->EndRecPtr = targetPagePtr + pageHeaderSize - + MAXALIGN(pageHeader->xlp_rem_len); - } - else - { - /* Wait for the record data to become available */ - while (XLogNeedData(state, targetPagePtr, - Min(targetRecOff + total_len, XLOG_BLCKSZ), true)) - { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + + pageHeaderSize = + XLogPageHeaderSize((XLogPageHeader) state->readBuf); + state->EndRecPtr = targetPagePtr + pageHeaderSize + + MAXALIGN(pageHeader->xlp_rem_len); + + *record = prec; + state->readRecordState = XLREAD_NEXT_RECORD; break; - } - - if (!state->page_verified) - goto err; - - /* Record does not cross a page boundary */ - if (!ValidXLogRecord(state, record, RecPtr)) - goto err; - - state->EndRecPtr = RecPtr + MAXALIGN(total_len); - - state->ReadRecPtr = RecPtr; + } } /* * Special processing if it's an XLOG SWITCH record */ - if (record->xl_rmid == RM_XLOG_ID && - (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) + if ((*record)->xl_rmid == RM_XLOG_ID && + ((*record)->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH) { /* Pretend it extends to end of segment */ state->EndRecPtr += state->segcxt.ws_segsize - 1; state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize); } - if (DecodeXLogRecord(state, record, errormsg)) - return record; - else - return NULL; + Assert(!*record || state->readLen >= 0); + if (DecodeXLogRecord(state, *record, errormsg)) + return XLREAD_SUCCESS; + + *record = NULL; + return XLREAD_FAIL; err: - if (assembled) + Assert(state->readRecordState != XLREAD_NEXT_RECORD); + XLogTerminateRead(state); + + if (state->errormsg_buf[0] != '\0') + *errormsg = state->errormsg_buf; + + *record = NULL; + + return XLREAD_FAIL; +} + +/* + * Terminate read WAL. + * + * When the caller failed to read the data requested from XLogReadRecord, it is + * supposed to call this function to set the correct reader state to reflect + * the failure. + */ +void +XLogTerminateRead(XLogReaderState *state) +{ + if (state->readRecordState == XLREAD_CONTINUATION) { /* * We get here when a record that spans multiple pages needs to be @@ -640,20 +768,15 @@ err: * in turn signal downstream WAL consumers that the broken WAL record * is to be ignored. */ - state->abortedRecPtr = RecPtr; - state->missingContrecPtr = targetPagePtr; + state->abortedRecPtr = state->ReadRecPtr; + state->missingContrecPtr = state->recordContRecPtr; } /* - * Invalidate the read state. We might read from a different source after + * Invalidate the read page. We might read from a different source after * failure. */ XLogReaderInvalReadState(state); - - if (state->errormsg_buf[0] != '\0') - *errormsg = state->errormsg_buf; - - return NULL; } /* @@ -805,11 +928,12 @@ XLogReaderInvalReadState(XLogReaderState *state) * * This is just a convenience subroutine to avoid duplicated code in * XLogReadRecord. It's not intended for use from anywhere else. + * + * If PrevRecPtr is valid, the xl_prev is is cross-checked with it. */ static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, - XLogRecPtr PrevRecPtr, XLogRecord *record, - bool randAccess) + XLogRecPtr PrevRecPtr, XLogRecord *record) { if (record->xl_tot_len < SizeOfXLogRecord) { @@ -826,7 +950,7 @@ ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, record->xl_rmid, LSN_FORMAT_ARGS(RecPtr)); return false; } - if (randAccess) + if (PrevRecPtr == InvalidXLogRecPtr) { /* * We can't exactly verify the prev-link, but surely it should be less @@ -1056,11 +1180,14 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, * XLogReadRecord() will read the next valid record. */ XLogRecPtr -XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) +XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private) { XLogRecPtr tmpRecPtr; XLogRecPtr found = InvalidXLogRecPtr; XLogPageHeader header; + XLogRecord *record; + XLogReadRecordResult result; char *errormsg; Assert(!XLogRecPtrIsInvalid(RecPtr)); @@ -1093,9 +1220,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) while (XLogNeedData(state, targetPagePtr, targetRecOff, targetRecOff != 0)) { - if (!state->routine.page_read(state, state->readPagePtr, - state->readLen, - state->ReadRecPtr, state->readBuf)) + if (!read_page(state, private)) break; } @@ -1147,8 +1272,16 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr) * or we just jumped over the remaining data of a continuation. */ XLogBeginRead(state, tmpRecPtr); - while (XLogReadRecord(state, &errormsg) != NULL) + while ((result = XLogReadRecord(state, &record, &errormsg)) != + XLREAD_FAIL) { + if (result == XLREAD_NEED_DATA) + { + if (!read_page(state, private)) + goto err; + continue; + } + /* past the record we've found, break out */ if (RecPtr <= state->ReadRecPtr) { @@ -1168,9 +1301,9 @@ err: #endif /* FRONTEND */ /* - * Helper function to ease writing of XLogRoutine->page_read callbacks. - * If this function is used, caller must supply a segment_open callback in - * 'state', as that is used here. + * Helper function to ease writing of page_read callback. + * If this function is used, caller must supply a segment_open callback and + * segment_close callback as that is used here. * * Read 'count' bytes into 'buf', starting at location 'startptr', from WAL * fetched from timeline 'tli'. @@ -1183,6 +1316,7 @@ err: */ bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB segclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo) { @@ -1214,10 +1348,10 @@ WALRead(XLogReaderState *state, XLogSegNo nextSegNo; if (state->seg.ws_file >= 0) - state->routine.segment_close(state); + segclosefn(state); XLByteToSeg(recptr, nextSegNo, state->segcxt.ws_segsize); - state->routine.segment_open(state, nextSegNo, &tli); + segopenfn(state, nextSegNo, &tli); /* This shouldn't happen -- indicates a bug in segment_open */ Assert(state->seg.ws_file >= 0); diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 421040f391..fc09a72b8b 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -706,8 +706,7 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum, void XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wantLength) { - const XLogRecPtr lastReadPage = state->seg.ws_segno * - state->segcxt.ws_segsize + state->readLen; + const XLogRecPtr lastReadPage = state->readPagePtr; Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0); Assert(wantLength <= XLOG_BLCKSZ); @@ -722,7 +721,7 @@ XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage, uint32 wa * current TLI has since become historical. */ if (lastReadPage == wantPage && - state->readLen != 0 && + state->page_verified && lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1)) return; @@ -808,6 +807,7 @@ wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, char path[MAXPGPATH]; XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize); + elog(LOG, "HOGE: %lu, %d => %s", nextSegNo, tli, path); state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY); if (state->seg.ws_file >= 0) return; @@ -845,9 +845,11 @@ wal_segment_close(XLogReaderState *state) * loop for now. */ bool -read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *cur_page) +read_local_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr read_upto, loc; TimeLineID tli; @@ -960,11 +962,12 @@ read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, - &errinfo)) + if (!WALRead(state, wal_segment_open, wal_segment_close, + cur_page, targetPagePtr, XLOG_BLCKSZ, tli, &errinfo)) WALReadRaiseError(&errinfo); /* number of valid bytes in the buffer */ + state->readPagePtr = targetPagePtr; state->readLen = count; return true; } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index aae0ae5b8a..2a88aa063a 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -148,7 +148,8 @@ StartupDecodingContext(List *output_plugin_options, TransactionId xmin_horizon, bool need_full_snapshot, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -198,11 +199,12 @@ StartupDecodingContext(List *output_plugin_options, ctx->slot = slot; - ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, xl_routine, ctx); + ctx->reader = XLogReaderAllocate(wal_segment_size, NULL, cleanup_cb); if (!ctx->reader) ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); + ctx->page_read = page_read; ctx->reorder = ReorderBufferAllocate(); ctx->snapshot_builder = @@ -319,7 +321,8 @@ CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -422,7 +425,7 @@ CreateInitDecodingContext(const char *plugin, ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon, need_full_snapshot, false, - xl_routine, prepare_write, do_write, + page_read, cleanup_cb, prepare_write, do_write, update_progress); /* call output plugin initialization callback */ @@ -478,7 +481,8 @@ LogicalDecodingContext * CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress) @@ -534,8 +538,8 @@ CreateDecodingContext(XLogRecPtr start_lsn, ctx = StartupDecodingContext(output_plugin_options, start_lsn, InvalidTransactionId, false, - fast_forward, xl_routine, prepare_write, - do_write, update_progress); + fast_forward, page_read, cleanup_cb, + prepare_write, do_write, update_progress); /* call output plugin initialization callback */ old_context = MemoryContextSwitchTo(ctx->context); @@ -603,7 +607,16 @@ DecodingContextFindStartpoint(LogicalDecodingContext *ctx) char *err = NULL; /* the read_page callback waits for new WAL */ - record = XLogReadRecord(ctx->reader, &err); + while (XLogReadRecord(ctx->reader, &record, &err) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + { + XLogTerminateRead(ctx->reader); + break; + } + } + if (err) elog(ERROR, "%s", err); if (!record) diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index e59939aad1..f68d08fdee 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -224,9 +224,8 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); @@ -275,7 +274,16 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin XLogRecord *record; char *errm = NULL; - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + { + XLogTerminateRead(ctx->reader); + break; + } + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 17df99c2ac..57426aa9d7 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -144,9 +144,8 @@ create_logical_replication_slot(char *name, char *plugin, ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ restart_lsn, - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -503,9 +502,8 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) ctx = CreateDecodingContext(InvalidXLogRecPtr, NIL, true, /* fast_forward */ - XL_ROUTINE(.page_read = read_local_xlog_page, - .segment_open = wal_segment_open, - .segment_close = wal_segment_close), + read_local_xlog_page, + wal_segment_close, NULL, NULL, NULL); /* @@ -527,7 +525,16 @@ pg_logical_replication_slot_advance(XLogRecPtr moveto) * Read records. No changes are generated in fast_forward mode, * but snapbuilder/slot statuses are updated properly. */ - record = XLogReadRecord(ctx->reader, &errm); + while (XLogReadRecord(ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!ctx->page_read(ctx->reader)) + { + XLogTerminateRead(ctx->reader); + break; + } + } + if (errm) elog(ERROR, "%s", errm); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index ddba340653..78d805ab80 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -575,10 +575,7 @@ StartReplication(StartReplicationCmd *cmd) /* create xlogreader for physical replication */ xlogreader = - XLogReaderAllocate(wal_segment_size, NULL, - XL_ROUTINE(.segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), - NULL); + XLogReaderAllocate(wal_segment_size, NULL, wal_segment_close); if (!xlogreader) ereport(ERROR, @@ -803,9 +800,11 @@ StartReplication(StartReplicationCmd *cmd) * set every time WAL is flushed. */ static bool -logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page) +logical_read_xlog_page(XLogReaderState *state) { + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *cur_page = state->readBuf; XLogRecPtr flushptr; int count; WALReadError errinfo; @@ -833,7 +832,7 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req count = flushptr - targetPagePtr; /* part of the page available */ /* now actually read the data, we know it's there */ - if (!WALRead(state, + if (!WALRead(state, WalSndSegmentOpen, wal_segment_close, cur_page, targetPagePtr, XLOG_BLCKSZ, @@ -1023,9 +1022,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, InvalidXLogRecPtr, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); @@ -1183,9 +1181,8 @@ StartLogicalReplication(StartReplicationCmd *cmd) */ logical_decoding_ctx = CreateDecodingContext(cmd->startpoint, cmd->options, false, - XL_ROUTINE(.page_read = logical_read_xlog_page, - .segment_open = WalSndSegmentOpen, - .segment_close = wal_segment_close), + logical_read_xlog_page, + wal_segment_close, WalSndPrepareWrite, WalSndWriteData, WalSndUpdateProgress); xlogreader = logical_decoding_ctx->reader; @@ -2778,7 +2775,7 @@ XLogSendPhysical(void) enlargeStringInfo(&output_message, nbytes); retry: - if (!WALRead(xlogreader, + if (!WALRead(xlogreader, WalSndSegmentOpen, wal_segment_close, &output_message.data[output_message.len], startptr, nbytes, @@ -2876,7 +2873,15 @@ XLogSendLogical(void) */ WalSndCaughtUp = false; - record = XLogReadRecord(logical_decoding_ctx->reader, &errm); + while (XLogReadRecord(logical_decoding_ctx->reader, &record, &errm) == + XLREAD_NEED_DATA) + { + if (!logical_decoding_ctx->page_read(logical_decoding_ctx->reader)) + { + XLogTerminateRead(logical_decoding_ctx->reader); + break; + } + } /* xlog record was invalid */ if (errm != NULL) diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index cf119848b0..da723e5340 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -41,15 +41,9 @@ static int xlogreadfd = -1; static XLogSegNo xlogreadsegno = -1; static char xlogfpath[MAXPGPATH]; -typedef struct XLogPageReadPrivate -{ - const char *restoreCommand; - int tliIndex; -} XLogPageReadPrivate; - -static bool SimpleXLogPageRead(XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf); +static bool SimpleXLogPageRead(XLogReaderState *xlogreader, + const char *datadir, int *tliIndex, + const char *restoreCommand); /* * Read WAL from the datadir/pg_wal, starting from 'startpoint' on timeline @@ -66,20 +60,25 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); + if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, startpoint); do { - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + { + XLogTerminateRead(xlogreader); + break; + } + } if (record == NULL) { @@ -123,19 +122,22 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex, XLogRecord *record; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; XLogRecPtr endptr; - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); XLogBeginRead(xlogreader, ptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, &tliIndex, restoreCommand)) + { + XLogTerminateRead(xlogreader); + break; + } + } if (record == NULL) { if (errormsg) @@ -170,7 +172,6 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogRecPtr searchptr; XLogReaderState *xlogreader; char *errormsg; - XLogPageReadPrivate private; /* * The given fork pointer points to the end of the last common record, @@ -186,11 +187,7 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, forkptr += SizeOfXLogShortPHD; } - private.tliIndex = tliIndex; - private.restoreCommand = restoreCommand; - xlogreader = XLogReaderAllocate(WalSegSz, datadir, - XL_ROUTINE(.page_read = &SimpleXLogPageRead), - &private); + xlogreader = XLogReaderAllocate(WalSegSz, datadir, NULL); if (xlogreader == NULL) pg_fatal("out of memory"); @@ -200,7 +197,16 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, uint8 info; XLogBeginRead(xlogreader, searchptr); - record = XLogReadRecord(xlogreader, &errormsg); + while (XLogReadRecord(xlogreader, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!SimpleXLogPageRead(xlogreader, datadir, + &tliIndex, restoreCommand)) + { + XLogTerminateRead(xlogreader); + break; + } + } if (record == NULL) { @@ -247,10 +253,11 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, /* XLogReader callback function, to read a WAL page */ static bool -SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, - int reqLen, XLogRecPtr targetRecPtr, char *readBuf) +SimpleXLogPageRead(XLogReaderState *xlogreader, const char *datadir, + int *tliIndex, const char *restoreCommand) { - XLogPageReadPrivate *private = (XLogPageReadPrivate *) xlogreader->private_data; + XLogRecPtr targetPagePtr = xlogreader->readPagePtr; + char *readBuf = xlogreader->readBuf; uint32 targetPageOff; XLogRecPtr targetSegEnd; XLogSegNo targetSegNo; @@ -283,14 +290,14 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, * be done both forward and backward, consider also switching timeline * accordingly. */ - while (private->tliIndex < targetNentries - 1 && - targetHistory[private->tliIndex].end < targetSegEnd) - private->tliIndex++; - while (private->tliIndex > 0 && - targetHistory[private->tliIndex].begin >= targetSegEnd) - private->tliIndex--; + while (*tliIndex < targetNentries - 1 && + targetHistory[*tliIndex].end < targetSegEnd) + (*tliIndex)++; + while (*tliIndex > 0 && + targetHistory[*tliIndex].begin >= targetSegEnd) + (*tliIndex)--; - XLogFileName(xlogfname, targetHistory[private->tliIndex].tli, + XLogFileName(xlogfname, targetHistory[*tliIndex].tli, xlogreadsegno, WalSegSz); snprintf(xlogfpath, MAXPGPATH, "%s/" XLOGDIR "/%s", @@ -303,7 +310,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, /* * If we have no restore_command to execute, then exit. */ - if (private->restoreCommand == NULL) + if (restoreCommand == NULL) { pg_log_error("could not open file \"%s\": %m", xlogfpath); xlogreader->readLen = -1; @@ -317,7 +324,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, xlogreadfd = RestoreArchivedFile(xlogreader->segcxt.ws_dir, xlogfname, WalSegSz, - private->restoreCommand); + restoreCommand); if (xlogreadfd < 0) { @@ -359,7 +366,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, Assert(targetSegNo == xlogreadsegno); - xlogreader->seg.ws_tli = targetHistory[private->tliIndex].tli; + xlogreader->seg.ws_tli = targetHistory[*tliIndex].tli; xlogreader->readLen = XLOG_BLCKSZ; return true; } diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 833a64210b..80182621f8 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -331,12 +331,17 @@ WALDumpCloseSegment(XLogReaderState *state) state->seg.ws_file = -1; } -/* pg_waldump's XLogReaderRoutine->page_read callback */ +/* + * pg_waldump's WAL page rader, also used as page_read callback for + * XLogFindNextRecord + */ static bool -WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetPtr, char *readBuff) +WALDumpReadPage(XLogReaderState *state, void *priv) { - XLogDumpPrivate *private = state->private_data; + XLogRecPtr targetPagePtr = state->readPagePtr; + int reqLen = state->readLen; + char *readBuff = state->readBuf; + XLogDumpPrivate *private = (XLogDumpPrivate *) priv; int count = XLOG_BLCKSZ; WALReadError errinfo; @@ -354,8 +359,8 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, } } - if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline, - &errinfo)) + if (!WALRead(state, WALDumpOpenSegment, WALDumpCloseSegment, + readBuff, targetPagePtr, count, private->timeline, &errinfo)) { WALOpenSegment *seg = &errinfo.wre_seg; char fname[MAXPGPATH]; @@ -375,6 +380,7 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen, errinfo.wre_req); } + Assert(count >= state->readLen); state->readLen = count; return true; } @@ -1057,16 +1063,14 @@ main(int argc, char **argv) /* we have everything we need, start reading */ xlogreader_state = - XLogReaderAllocate(WalSegSz, waldir, - XL_ROUTINE(.page_read = WALDumpReadPage, - .segment_open = WALDumpOpenSegment, - .segment_close = WALDumpCloseSegment), - &private); + XLogReaderAllocate(WalSegSz, waldir, WALDumpCloseSegment); + if (!xlogreader_state) fatal_error("out of memory"); /* first find a valid recptr to start from */ - first_record = XLogFindNextRecord(xlogreader_state, private.startptr); + first_record = XLogFindNextRecord(xlogreader_state, private.startptr, + &WALDumpReadPage, (void*) &private); if (first_record == InvalidXLogRecPtr) fatal_error("could not find a valid record after %X/%X", @@ -1089,7 +1093,16 @@ main(int argc, char **argv) for (;;) { /* try to read the next record */ - record = XLogReadRecord(xlogreader_state, &errormsg); + while (XLogReadRecord(xlogreader_state, &record, &errormsg) == + XLREAD_NEED_DATA) + { + if (!WALDumpReadPage(xlogreader_state, (void *) &private)) + { + XLogTerminateRead(xlogreader_state); + break; + } + } + if (!record) { if (!config.follow || private.endptr_reached) diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index f3cf4f2f49..ff1aca719b 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -57,64 +57,15 @@ typedef struct WALSegmentContext typedef struct XLogReaderState XLogReaderState; -/* Function type definition for the read_page callback */ -typedef bool (*XLogPageReadCB) (XLogReaderState *xlogreader, - XLogRecPtr targetPagePtr, - int reqLen, - XLogRecPtr targetRecPtr, - char *readBuf); +/* Function type definition for the segment cleanup callback */ +typedef void (*WALSegmentCleanupCB) (XLogReaderState *xlogreader); + +/* Function type definition for the open/close callbacks for WALRead() */ typedef void (*WALSegmentOpenCB) (XLogReaderState *xlogreader, XLogSegNo nextSegNo, TimeLineID *tli_p); typedef void (*WALSegmentCloseCB) (XLogReaderState *xlogreader); -typedef struct XLogReaderRoutine -{ - /* - * Data input callback - * - * This callback shall read at least reqLen valid bytes of the xlog page - * starting at targetPagePtr, and store them in readBuf. The callback - * shall return the number of bytes read (never more than XLOG_BLCKSZ), or - * -1 on failure. The callback shall sleep, if necessary, to wait for the - * requested bytes to become available. The callback will not be invoked - * again for the same page unless more than the returned number of bytes - * are needed. - * - * targetRecPtr is the position of the WAL record we're reading. Usually - * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs - * to read and verify the page or segment header, before it reads the - * actual WAL record it's interested in. In that case, targetRecPtr can - * be used to determine which timeline to read the page from. - * - * The callback shall set ->seg.ws_tli to the TLI of the file the page was - * read from. - */ - XLogPageReadCB page_read; - - /* - * Callback to open the specified WAL segment for reading. ->seg.ws_file - * shall be set to the file descriptor of the opened segment. In case of - * failure, an error shall be raised by the callback and it shall not - * return. - * - * "nextSegNo" is the number of the segment to be opened. - * - * "tli_p" is an input/output argument. WALRead() uses it to pass the - * timeline in which the new segment should be found, but the callback can - * use it to return the TLI that it actually opened. - */ - WALSegmentOpenCB segment_open; - - /* - * WAL segment close callback. ->seg.ws_file shall be set to a negative - * number. - */ - WALSegmentCloseCB segment_close; -} XLogReaderRoutine; - -#define XL_ROUTINE(...) &(XLogReaderRoutine){__VA_ARGS__} - typedef struct { /* Is this block ref in use? */ @@ -144,12 +95,36 @@ typedef struct uint16 data_bufsz; } DecodedBkpBlock; +/* Return code from XLogReadRecord */ +typedef enum XLogReadRecordResult +{ + XLREAD_SUCCESS, /* record is successfully read */ + XLREAD_NEED_DATA, /* need more data. see XLogReadRecord. */ + XLREAD_FAIL /* failed during reading a record */ +} XLogReadRecordResult; + +/* + * internal state of XLogReadRecord + * + * XLogReadState runs a state machine while reading a record. Theses states + * are not seen outside the function. Each state may repeat several times + * exiting requesting caller for new data. See the comment of XLogReadRecrod + * for details. + */ +typedef enum XLogReadRecordState +{ + XLREAD_NEXT_RECORD, + XLREAD_TOT_LEN, + XLREAD_FIRST_FRAGMENT, + XLREAD_CONTINUATION +} XLogReadRecordState; + struct XLogReaderState { /* * Operational callbacks */ - XLogReaderRoutine routine; + WALSegmentCleanupCB cleanup_cb; /* ---------------------------------------- * Public parameters @@ -162,18 +137,14 @@ struct XLogReaderState */ uint64 system_identifier; - /* - * Opaque data for callbacks to use. Not used by XLogReader. - */ - void *private_data; - /* * Start and end point of last record read. EndRecPtr is also used as the * position to read next. Calling XLogBeginRead() sets EndRecPtr to the * starting position and ReadRecPtr to invalid. */ - XLogRecPtr ReadRecPtr; /* start of last record read */ + XLogRecPtr ReadRecPtr; /* start of last record read or being read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + XLogRecPtr PrevRecPtr; /* start of previous record read */ /* * Set at the end of recovery: the start point of a partial record at the @@ -196,7 +167,9 @@ struct XLogReaderState * read by reader, which must be larger than * the request, or -1 on error */ char *readBuf; /* buffer to store data */ - bool page_verified; /* is the page on the buffer verified? */ + bool page_verified; /* is the page header on the buffer verified? */ + bool record_verified; /* is the current record header verified? */ + /* ---------------------------------------- * Decoded representation of current record @@ -237,8 +210,6 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; - /* beginning of the WAL record being read. */ - XLogRecPtr currRecPtr; /* timeline to read it from, 0 if a lookup is required */ TimeLineID currTLI; @@ -265,6 +236,15 @@ struct XLogReaderState char *readRecordBuf; uint32 readRecordBufSize; + /* + * XLogReadRecord() state + */ + XLogReadRecordState readRecordState; /* state machine state */ + int recordGotLen; /* amount of current record that has already + * been read */ + int recordRemainLen; /* length of current record that remains */ + XLogRecPtr recordContRecPtr; /* where the current record continues */ + /* Buffer to hold error message */ char *errormsg_buf; }; @@ -272,9 +252,7 @@ struct XLogReaderState /* Get a new XLogReader */ extern XLogReaderState *XLogReaderAllocate(int wal_segment_size, const char *waldir, - XLogReaderRoutine *routine, - void *private_data); -extern XLogReaderRoutine *LocalXLogReaderRoutine(void); + WALSegmentCleanupCB cleanup_cb); /* Free an XLogReader */ extern void XLogReaderFree(XLogReaderState *state); @@ -282,12 +260,19 @@ extern void XLogReaderFree(XLogReaderState *state); /* Position the XLogReader to given record */ extern void XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr); #ifdef FRONTEND -extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); +/* Function type definition for the read_page callback */ +typedef bool (*XLogFindNextRecordCB) (XLogReaderState *xlogreader, + void *private); +extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr, + XLogFindNextRecordCB read_page, void *private); #endif /* FRONTEND */ /* Read the next XLog record. Returns NULL on end-of-WAL or failure */ -extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, - char **errormsg); +extern XLogReadRecordResult XLogReadRecord(XLogReaderState *state, + XLogRecord **record, + char **errormsg); +/* Finalize function when the caller of XLogReadRecord failed */ +extern void XLogTerminateRead(XLogReaderState *state); /* Validate a page */ extern bool XLogReaderValidatePageHeader(XLogReaderState *state, @@ -307,6 +292,7 @@ typedef struct WALReadError } WALReadError; extern bool WALRead(XLogReaderState *state, + WALSegmentOpenCB segopenfn, WALSegmentCloseCB sgclosefn, char *buf, XLogRecPtr startptr, Size count, TimeLineID tli, WALReadError *errinfo); diff --git a/src/include/access/xlogutils.h b/src/include/access/xlogutils.h index 8669f7eeb3..e403d253d6 100644 --- a/src/include/access/xlogutils.h +++ b/src/include/access/xlogutils.h @@ -89,9 +89,7 @@ extern Buffer XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum, extern Relation CreateFakeRelcacheEntry(RelFileNode rnode); extern void FreeFakeRelcacheEntry(Relation fakerel); -extern bool read_local_xlog_page(XLogReaderState *state, - XLogRecPtr targetPagePtr, int reqLen, - XLogRecPtr targetRecPtr, char *cur_page); +extern bool read_local_xlog_page(XLogReaderState *state); extern void wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo, TimeLineID *tli_p); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index 614035e215..fecffdb3f6 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -390,7 +390,7 @@ * Enable debugging print statements for WAL-related operations; see * also the wal_debug GUC var. */ -/* #define WAL_DEBUG */ +#define WAL_DEBUG /* * Enable tracing of resource consumption during sort operations; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index e0f513b773..3346188b48 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -29,6 +29,10 @@ typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingC TransactionId xid ); +typedef struct LogicalDecodingContext LogicalDecodingContext; + +typedef bool (*LogicalDecodingXLogPageReadCB)(XLogReaderState *ctx); + typedef struct LogicalDecodingContext { /* memory context this is all allocated in */ @@ -39,6 +43,7 @@ typedef struct LogicalDecodingContext /* infrastructure pieces for decoding */ XLogReaderState *reader; + LogicalDecodingXLogPageReadCB page_read; struct ReorderBuffer *reorder; struct SnapBuild *snapshot_builder; @@ -115,14 +120,16 @@ extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn, List *output_plugin_options, bool fast_forward, - XLogReaderRoutine *xl_routine, + LogicalDecodingXLogPageReadCB page_read, + WALSegmentCleanupCB cleanup_cb, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress); -- 2.27.0 ----Next_Part(Thu_Oct__7_17_28_20_2021_531)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v18-0003-Remove-globals-readOff-readLen-and-readSegNo.patch" ^ permalink raw reply [nested|flat] 52+ messages in thread
* Define STATS_MIN_ROWS for minimum rows of stats in ANALYZE @ 2024-12-09 13:10 Ilia Evdokimov <[email protected]> 0 siblings, 0 replies; 52+ messages in thread From: Ilia Evdokimov @ 2024-12-09 13:10 UTC (permalink / raw) To: pgsql-hackers Hi hackers, The repeated use of the number 300 in the ANALYZE-related code creates redundancy and relies on scattered, sometimes unclear, comments to explain its purpose. This can make the code harder to understand, especially for new contributors who might not immediately understand its significance. To address this, I propose introducing a macro STATS_MIN_ROWS to represent this value and consolidating its explanation in a single place, making the code more consistent and readable. -- Best regards, Ilia Evdokimov, Tantor Labs LLC. Attachments: [text/x-patch] v1-0001-Define-STATS_MIN_ROWS-for-minimum-rows-of-stats.patch (6.3K, ../../[email protected]/2-v1-0001-Define-STATS_MIN_ROWS-for-minimum-rows-of-stats.patch) download | inline diff: From d3cbea3875fdc9866c86c64c0d0e0d838887040c Mon Sep 17 00:00:00 2001 From: Ilia Evdokimov <[email protected]> Date: Mon, 9 Dec 2024 15:50:40 +0300 Subject: [PATCH v1] Define STATS_MIN_ROWS for minimum rows of stats in ANALYZE This introduces a macro STATS_MIN_ROWS to represent the default minimum number of rows (300) sampled in ANALYZE. --- src/backend/commands/analyze.c | 26 ++----------------- src/backend/statistics/extended_stats.c | 2 +- src/backend/tsearch/ts_typanalyze.c | 4 +-- src/backend/utils/adt/rangetypes_typanalyze.c | 7 +++-- src/include/statistics/statistics.h | 23 ++++++++++++++++ 5 files changed, 31 insertions(+), 31 deletions(-) diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c index 9a56de2282..ff7b6ffe8f 100644 --- a/src/backend/commands/analyze.c +++ b/src/backend/commands/analyze.c @@ -1897,42 +1897,20 @@ std_typanalyze(VacAttrStats *stats) { /* Seems to be a scalar datatype */ stats->compute_stats = compute_scalar_stats; - /*-------------------- - * The following choice of minrows is based on the paper - * "Random sampling for histogram construction: how much is enough?" - * by Surajit Chaudhuri, Rajeev Motwani and Vivek Narasayya, in - * Proceedings of ACM SIGMOD International Conference on Management - * of Data, 1998, Pages 436-447. Their Corollary 1 to Theorem 5 - * says that for table size n, histogram size k, maximum relative - * error in bin size f, and error probability gamma, the minimum - * random sample size is - * r = 4 * k * ln(2*n/gamma) / f^2 - * Taking f = 0.5, gamma = 0.01, n = 10^6 rows, we obtain - * r = 305.82 * k - * Note that because of the log function, the dependence on n is - * quite weak; even at n = 10^12, a 300*k sample gives <= 0.66 - * bin size error with probability 0.99. So there's no real need to - * scale for n, which is a good thing because we don't necessarily - * know it at this point. - *-------------------- - */ - stats->minrows = 300 * stats->attstattarget; } else if (OidIsValid(eqopr)) { /* We can still recognize distinct values */ stats->compute_stats = compute_distinct_stats; - /* Might as well use the same minrows as above */ - stats->minrows = 300 * stats->attstattarget; } else { /* Can't do much but the trivial stuff */ stats->compute_stats = compute_trivial_stats; - /* Might as well use the same minrows as above */ - stats->minrows = 300 * stats->attstattarget; } + stats->minrows = (STATS_MIN_ROWS * stats->attstattarget); + return true; } diff --git a/src/backend/statistics/extended_stats.c b/src/backend/statistics/extended_stats.c index 99fdf208db..451e2d1e9c 100644 --- a/src/backend/statistics/extended_stats.c +++ b/src/backend/statistics/extended_stats.c @@ -320,7 +320,7 @@ ComputeExtStatisticsRows(Relation onerel, MemoryContextDelete(cxt); /* compute sample size based on the statistics target */ - return (300 * result); + return (STATS_MIN_ROWS * result); } /* diff --git a/src/backend/tsearch/ts_typanalyze.c b/src/backend/tsearch/ts_typanalyze.c index ccafe42729..befd90c9d5 100644 --- a/src/backend/tsearch/ts_typanalyze.c +++ b/src/backend/tsearch/ts_typanalyze.c @@ -17,6 +17,7 @@ #include "catalog/pg_operator.h" #include "commands/vacuum.h" #include "common/hashfn.h" +#include "statistics/statistics.h" #include "tsearch/ts_type.h" #include "utils/builtins.h" #include "varatt.h" @@ -64,8 +65,7 @@ ts_typanalyze(PG_FUNCTION_ARGS) stats->attstattarget = default_statistics_target; stats->compute_stats = compute_tsvector_stats; - /* see comment about the choice of minrows in commands/analyze.c */ - stats->minrows = 300 * stats->attstattarget; + stats->minrows = (STATS_MIN_ROWS * stats->attstattarget); PG_RETURN_BOOL(true); } diff --git a/src/backend/utils/adt/rangetypes_typanalyze.c b/src/backend/utils/adt/rangetypes_typanalyze.c index 3773f98115..7fcac5621c 100644 --- a/src/backend/utils/adt/rangetypes_typanalyze.c +++ b/src/backend/utils/adt/rangetypes_typanalyze.c @@ -26,6 +26,7 @@ #include "catalog/pg_operator.h" #include "commands/vacuum.h" +#include "statistics/statistics.h" #include "utils/float.h" #include "utils/fmgrprotos.h" #include "utils/lsyscache.h" @@ -56,8 +57,7 @@ range_typanalyze(PG_FUNCTION_ARGS) stats->compute_stats = compute_range_stats; stats->extra_data = typcache; - /* same as in std_typanalyze */ - stats->minrows = 300 * stats->attstattarget; + stats->minrows = (STATS_MIN_ROWS * stats->attstattarget); PG_RETURN_BOOL(true); } @@ -82,8 +82,7 @@ multirange_typanalyze(PG_FUNCTION_ARGS) stats->compute_stats = compute_range_stats; stats->extra_data = typcache; - /* same as in std_typanalyze */ - stats->minrows = 300 * stats->attstattarget; + stats->minrows = (STATS_MIN_ROWS * stats->attstattarget); PG_RETURN_BOOL(true); } diff --git a/src/include/statistics/statistics.h b/src/include/statistics/statistics.h index 7f2bf18716..f578f7fd1d 100644 --- a/src/include/statistics/statistics.h +++ b/src/include/statistics/statistics.h @@ -22,6 +22,29 @@ #define STATS_NDISTINCT_MAGIC 0xA352BFA4 /* struct identifier */ #define STATS_NDISTINCT_TYPE_BASIC 1 /* struct version */ +/*-------------------- + * Minimum of rows wanted for stats + * + * The following choice of minrows is based on the paper + * "Random sampling for histogram construction: how much is enough?" + * by Surajit Chaudhuri, Rajeev Motwani and Vivek Narasayya, in + * Proceedings of ACM SIGMOD International Conference on Management + * of Data, 1998, Pages 436-447. Their Corollary 1 to Theorem 5 + * says that for table size n, histogram size k, maximum relative + * error in bin size f, and error probability gamma, the minimum + * random sample size is + * r = 4 * k * ln(2*n/gamma) / f^2 + * Taking f = 0.5, gamma = 0.01, n = 10^6 rows, we obtain + * r = 305.82 * k + * Note that because of the log function, the dependence on n is + * quite weak; even at n = 10^12, a 300*k sample gives <= 0.66 + * bin size error with probability 0.99. So there's no real need to + * scale for n, which is a good thing because we don't necessarily + * know it at this point. + *-------------------- + */ +#define STATS_MIN_ROWS 300 + /* MVNDistinctItem represents a single combination of columns */ typedef struct MVNDistinctItem { -- 2.34.1 ^ permalink raw reply [nested|flat] 52+ messages in thread
end of thread, other threads:[~2024-12-09 13:10 UTC | newest] Thread overview: 52+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v15 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v15 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v15 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v15 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v15 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v15 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v15 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v15 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v15 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v13 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v16 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v15 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v15 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v15 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v9 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v15 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v10 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v8 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v15 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v15 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v15 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v15 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v15 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v15 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v15 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v17 2/4] Move page-reader out of XLogReadRecord Kyotaro Horiguchi <[email protected]> 2019-09-10 03:58 [PATCH v19 2/5] Move page-reader out of XLogReadRecord(). Kyotaro Horiguchi <[email protected]> 2021-09-30 03:04 [PATCH v18 2/5] Move page-reader out of XLogReadRecord(). Kyotaro Horiguchi <[email protected]> 2024-12-09 13:10 Define STATS_MIN_ROWS for minimum rows of stats in ANALYZE Ilia Evdokimov <[email protected]>
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