Date: Sun, 8 Jul 2018 14:23:45 -0400
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Pg Hackers <pgsql-hackers@postgresql.org>
Cc: Andres Freund <andres@anarazel.de>
Subject: XLogSegNoOffsetToRecPtr fixup
Message-ID: <20180708182345.imdgovmkffgtihhk@alvherre.pgsql>
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Pursuant to closing comment in 
https://postgr.es/m/20180306214239.ospkf6ie7aa5gm4j@alvherre.pgsql
here's a quick patch to change the order of arguments in
XLogSegNoOffsetToRecPtr.  Commit fc49e24fa69a ("Make WAL segment size
configurable at initdb time.") put the walsegsz as last argument,
*after* its output argument, which is downright weird.

I propose to apply this to pg11 and master, to avoid an unnecessary API
change in pg12.

-- 
Álvaro Herrera                         http://www.flickr.com/photos/alvherre/

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diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index d6b5b05425..f251989f0b 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -1971,7 +1971,7 @@ XLogBytePosToRecPtr(uint64 bytepos)
 		seg_offset += fullpages * XLOG_BLCKSZ + bytesleft + SizeOfXLogShortPHD;
 	}
 
-	XLogSegNoOffsetToRecPtr(fullsegs, seg_offset, result, wal_segment_size);
+	XLogSegNoOffsetToRecPtr(fullsegs, seg_offset, wal_segment_size, result);
 
 	return result;
 }
@@ -2017,7 +2017,7 @@ XLogBytePosToEndRecPtr(uint64 bytepos)
 			seg_offset += fullpages * XLOG_BLCKSZ + bytesleft + SizeOfXLogShortPHD;
 	}
 
-	XLogSegNoOffsetToRecPtr(fullsegs, seg_offset, result, wal_segment_size);
+	XLogSegNoOffsetToRecPtr(fullsegs, seg_offset, wal_segment_size, result);
 
 	return result;
 }
diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c
index dd96cef8f0..4c633c6c49 100644
--- a/src/backend/access/transam/xlogreader.c
+++ b/src/backend/access/transam/xlogreader.c
@@ -747,7 +747,7 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr,
 	XLByteToSeg(recptr, segno, state->wal_segment_size);
 	offset = XLogSegmentOffset(recptr, state->wal_segment_size);
 
-	XLogSegNoOffsetToRecPtr(segno, offset, recaddr, state->wal_segment_size);
+	XLogSegNoOffsetToRecPtr(segno, offset, state->wal_segment_size, recaddr);
 
 	if (hdr->xlp_magic != XLOG_PAGE_MAGIC)
 	{
diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index d3ec137051..9b55b94227 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -2782,7 +2782,7 @@ ReorderBufferSerializedPath(char *path, ReplicationSlot *slot, TransactionId xid
 {
 	XLogRecPtr	recptr;
 
-	XLogSegNoOffsetToRecPtr(segno, 0, recptr, wal_segment_size);
+	XLogSegNoOffsetToRecPtr(segno, 0, wal_segment_size, recptr);
 
 	snprintf(path, MAXPGPATH, "pg_replslot/%s/xid-%u-lsn-%X-%X.snap",
 			 NameStr(MyReplicationSlot->data.name),
diff --git a/src/bin/pg_basebackup/pg_receivewal.c b/src/bin/pg_basebackup/pg_receivewal.c
index 071b32d19d..ed9d7f6378 100644
--- a/src/bin/pg_basebackup/pg_receivewal.c
+++ b/src/bin/pg_basebackup/pg_receivewal.c
@@ -352,7 +352,7 @@ FindStreamingStart(uint32 *tli)
 		if (!high_ispartial)
 			high_segno++;
 
-		XLogSegNoOffsetToRecPtr(high_segno, 0, high_ptr, WalSegSz);
+		XLogSegNoOffsetToRecPtr(high_segno, 0, WalSegSz, high_ptr);
 
 		*tli = high_tli;
 		return high_ptr;
diff --git a/src/bin/pg_resetwal/pg_resetwal.c b/src/bin/pg_resetwal/pg_resetwal.c
index 8cff535692..d63a3a27f6 100644
--- a/src/bin/pg_resetwal/pg_resetwal.c
+++ b/src/bin/pg_resetwal/pg_resetwal.c
@@ -933,8 +933,8 @@ RewriteControlFile(void)
 	 * Adjust fields as needed to force an empty XLOG starting at
 	 * newXlogSegNo.
 	 */
-	XLogSegNoOffsetToRecPtr(newXlogSegNo, SizeOfXLogLongPHD,
-							ControlFile.checkPointCopy.redo, WalSegSz);
+	XLogSegNoOffsetToRecPtr(newXlogSegNo, SizeOfXLogLongPHD, WalSegSz,
+							ControlFile.checkPointCopy.redo);
 	ControlFile.checkPointCopy.time = (pg_time_t) time(NULL);
 
 	ControlFile.state = DB_SHUTDOWNED;
diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c
index b4c1f827a6..1689279767 100644
--- a/src/bin/pg_rewind/parsexlog.c
+++ b/src/bin/pg_rewind/parsexlog.c
@@ -248,7 +248,7 @@ SimpleXLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr,
 	XLogSegNo	targetSegNo;
 
 	XLByteToSeg(targetPagePtr, targetSegNo, WalSegSz);
-	XLogSegNoOffsetToRecPtr(targetSegNo + 1, 0, targetSegEnd, WalSegSz);
+	XLogSegNoOffsetToRecPtr(targetSegNo + 1, 0, WalSegSz, targetSegEnd);
 	targetPageOff = XLogSegmentOffset(targetPagePtr, WalSegSz);
 
 	/*
diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c
index 5c4f38e597..d41b831b18 100644
--- a/src/bin/pg_waldump/pg_waldump.c
+++ b/src/bin/pg_waldump/pg_waldump.c
@@ -1039,7 +1039,7 @@ main(int argc, char **argv)
 		XLogFromFileName(fname, &private.timeline, &segno, WalSegSz);
 
 		if (XLogRecPtrIsInvalid(private.startptr))
-			XLogSegNoOffsetToRecPtr(segno, 0, private.startptr, WalSegSz);
+			XLogSegNoOffsetToRecPtr(segno, 0, WalSegSz, private.startptr);
 		else if (!XLByteInSeg(private.startptr, segno, WalSegSz))
 		{
 			fprintf(stderr,
@@ -1053,7 +1053,7 @@ main(int argc, char **argv)
 
 		/* no second file specified, set end position */
 		if (!(optind + 1 < argc) && XLogRecPtrIsInvalid(private.endptr))
-			XLogSegNoOffsetToRecPtr(segno + 1, 0, private.endptr, WalSegSz);
+			XLogSegNoOffsetToRecPtr(segno + 1, 0, WalSegSz, private.endptr);
 
 		/* parse ENDSEG if passed */
 		if (optind + 1 < argc)
@@ -1076,8 +1076,8 @@ main(int argc, char **argv)
 							argv[optind + 1], argv[optind]);
 
 			if (XLogRecPtrIsInvalid(private.endptr))
-				XLogSegNoOffsetToRecPtr(endsegno + 1, 0, private.endptr,
-										WalSegSz);
+				XLogSegNoOffsetToRecPtr(endsegno + 1, 0, WalSegSz,
+										private.endptr);
 
 			/* set segno to endsegno for check of --end */
 			segno = endsegno;
diff --git a/src/include/access/xlog_internal.h b/src/include/access/xlog_internal.h
index 7c766836db..30610b3ea9 100644
--- a/src/include/access/xlog_internal.h
+++ b/src/include/access/xlog_internal.h
@@ -101,7 +101,7 @@ typedef XLogLongPageHeaderData *XLogLongPageHeader;
 #define XLogSegmentsPerXLogId(wal_segsz_bytes)	\
 	(UINT64CONST(0x100000000) / (wal_segsz_bytes))
 
-#define XLogSegNoOffsetToRecPtr(segno, offset, dest, wal_segsz_bytes) \
+#define XLogSegNoOffsetToRecPtr(segno, offset, wal_segsz_bytes, dest) \
 		(dest) = (segno) * (wal_segsz_bytes) + (offset)
 
 #define XLogSegmentOffset(xlogptr, wal_segsz_bytes)	\

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