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* [PATCH v3 12/17] Merge prune and freeze records
@ 2024-01-07 22:55 Melanie Plageman <[email protected]>
0 siblings, 0 replies; 15+ messages in thread
From: Melanie Plageman @ 2024-01-07 22:55 UTC (permalink / raw)
When there are both tuples to prune and freeze on a page, emit a single,
combined prune record containing the offsets for pruning and the freeze
plans and offsets for freezing. This will reduce the number of WAL
records emitted.
---
src/backend/access/heap/heapam.c | 42 ++++++++++++--
src/backend/access/heap/pruneheap.c | 85 +++++++++++++----------------
src/include/access/heapam_xlog.h | 20 +++++--
3 files changed, 90 insertions(+), 57 deletions(-)
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index a3691584c55..a8f35eba3c9 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -8803,24 +8803,28 @@ heap_xlog_prune(XLogReaderState *record)
if (action == BLK_NEEDS_REDO)
{
Page page = (Page) BufferGetPage(buffer);
- OffsetNumber *end;
OffsetNumber *redirected;
OffsetNumber *nowdead;
OffsetNumber *nowunused;
int nredirected;
int ndead;
int nunused;
+ int nplans;
Size datalen;
+ xl_heap_freeze_plan *plans;
+ OffsetNumber *frz_offsets;
+ int curoff = 0;
- redirected = (OffsetNumber *) XLogRecGetBlockData(record, 0, &datalen);
-
+ nplans = xlrec->nplans;
nredirected = xlrec->nredirected;
ndead = xlrec->ndead;
- end = (OffsetNumber *) ((char *) redirected + datalen);
+ nunused = xlrec->nunused;
+
+ plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, &datalen);
+ redirected = (OffsetNumber *) &plans[nplans];
nowdead = redirected + (nredirected * 2);
nowunused = nowdead + ndead;
- nunused = (end - nowunused);
- Assert(nunused >= 0);
+ frz_offsets = nowunused + nunused;
/* Update all line pointers per the record, and repair fragmentation */
heap_page_prune_execute(buffer,
@@ -8828,6 +8832,32 @@ heap_xlog_prune(XLogReaderState *record)
nowdead, ndead,
nowunused, nunused);
+ for (int p = 0; p < nplans; p++)
+ {
+ HeapTupleFreeze frz;
+
+ /*
+ * Convert freeze plan representation from WAL record into
+ * per-tuple format used by heap_execute_freeze_tuple
+ */
+ frz.xmax = plans[p].xmax;
+ frz.t_infomask2 = plans[p].t_infomask2;
+ frz.t_infomask = plans[p].t_infomask;
+ frz.frzflags = plans[p].frzflags;
+ frz.offset = InvalidOffsetNumber; /* unused, but be tidy */
+
+ for (int i = 0; i < plans[p].ntuples; i++)
+ {
+ OffsetNumber offset = frz_offsets[curoff++];
+ ItemId lp;
+ HeapTupleHeader tuple;
+
+ lp = PageGetItemId(page, offset);
+ tuple = (HeapTupleHeader) PageGetItem(page, lp);
+ heap_execute_freeze_tuple(tuple, &frz);
+ }
+ }
+
/*
* Note: we don't worry about updating the page's prunability hints.
* At worst this will cause an extra prune cycle to occur soon.
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index d77270ad0d6..994cf75c54e 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -619,6 +619,9 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
*/
PageClearFull(page);
+ if (do_freeze)
+ heap_freeze_prepared_tuples(buffer, frozen, presult->nfrozen);
+
MarkBufferDirty(buffer);
/*
@@ -629,10 +632,37 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
xl_heap_prune xlrec;
XLogRecPtr recptr;
+ xl_heap_freeze_plan plans[MaxHeapTuplesPerPage];
+ OffsetNumber offsets[MaxHeapTuplesPerPage];
+
xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
- xlrec.snapshotConflictHorizon = prstate.snapshotConflictHorizon;
xlrec.nredirected = prstate.nredirected;
xlrec.ndead = prstate.ndead;
+ xlrec.nunused = prstate.nunused;
+ xlrec.nplans = 0;
+
+ /*
+ * The snapshotConflictHorizon for the whole record should be the most
+ * conservative of all the horizons calculated for any of the possible
+ * modifications. If this record will prune tuples, any transactions
+ * on the standby older than the youngest xmax of the most recently
+ * removed tuple this record will prune will conflict. If this record
+ * will freeze tuples, any transactions on the standby with xids older
+ * than the youngest tuple this record will freeze will conflict.
+ */
+ if (do_freeze)
+ xlrec.snapshotConflictHorizon = Max(prstate.snapshotConflictHorizon,
+ frz_conflict_horizon);
+ else
+ xlrec.snapshotConflictHorizon = prstate.snapshotConflictHorizon;
+
+ /*
+ * Prepare deduplicated representation for use in WAL record
+ * Destructively sorts tuples array in-place.
+ */
+ if (do_freeze)
+ xlrec.nplans = heap_log_freeze_plan(frozen,
+ presult->nfrozen, plans, offsets);
XLogBeginInsert();
XLogRegisterData((char *) &xlrec, SizeOfHeapPrune);
@@ -644,6 +674,10 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
* pretend that they are. When XLogInsert stores the whole buffer,
* the offset arrays need not be stored too.
*/
+ if (xlrec.nplans > 0)
+ XLogRegisterBufData(0, (char *) plans,
+ xlrec.nplans * sizeof(xl_heap_freeze_plan));
+
if (prstate.nredirected > 0)
XLogRegisterBufData(0, (char *) prstate.redirected,
prstate.nredirected *
@@ -657,56 +691,13 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
XLogRegisterBufData(0, (char *) prstate.nowunused,
prstate.nunused * sizeof(OffsetNumber));
- recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
-
- PageSetLSN(BufferGetPage(buffer), recptr);
- }
-
- if (do_freeze)
- {
- Assert(presult->nfrozen > 0);
-
- heap_freeze_prepared_tuples(buffer, frozen, presult->nfrozen);
-
- MarkBufferDirty(buffer);
-
- /* Now WAL-log freezing if necessary */
- if (RelationNeedsWAL(relation))
- {
- xl_heap_freeze_plan plans[MaxHeapTuplesPerPage];
- OffsetNumber offsets[MaxHeapTuplesPerPage];
- int nplans;
- xl_heap_freeze_page xlrec;
- XLogRecPtr recptr;
-
- /*
- * Prepare deduplicated representation for use in WAL record
- * Destructively sorts tuples array in-place.
- */
- nplans = heap_log_freeze_plan(frozen, presult->nfrozen, plans, offsets);
-
- xlrec.snapshotConflictHorizon = frz_conflict_horizon;
- xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
- xlrec.nplans = nplans;
-
- XLogBeginInsert();
- XLogRegisterData((char *) &xlrec, SizeOfHeapFreezePage);
-
- /*
- * The freeze plan array and offset array are not actually in the
- * buffer, but pretend that they are. When XLogInsert stores the
- * whole buffer, the arrays need not be stored too.
- */
- XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
- XLogRegisterBufData(0, (char *) plans,
- nplans * sizeof(xl_heap_freeze_plan));
+ if (xlrec.nplans > 0)
XLogRegisterBufData(0, (char *) offsets,
presult->nfrozen * sizeof(OffsetNumber));
- recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_FREEZE_PAGE);
+ recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
- PageSetLSN(page, recptr);
- }
+ PageSetLSN(BufferGetPage(buffer), recptr);
}
END_CRIT_SECTION();
diff --git a/src/include/access/heapam_xlog.h b/src/include/access/heapam_xlog.h
index 6488dad5e64..22f236bb52a 100644
--- a/src/include/access/heapam_xlog.h
+++ b/src/include/access/heapam_xlog.h
@@ -231,23 +231,35 @@ typedef struct xl_heap_update
* during opportunistic pruning)
*
* The array of OffsetNumbers following the fixed part of the record contains:
+ * * for each freeze plan: the freeze plan
* * for each redirected item: the item offset, then the offset redirected to
* * for each now-dead item: the item offset
* * for each now-unused item: the item offset
- * The total number of OffsetNumbers is therefore 2*nredirected+ndead+nunused.
- * Note that nunused is not explicitly stored, but may be found by reference
- * to the total record length.
+ * * for each tuple frozen by the freeze plans: the offset of the item corresponding to that tuple
+ * The total number of OffsetNumbers is therefore
+ * (2*nredirected) + ndead + nunused + (sum[plan.ntuples for plan in plans])
*
* Acquires a full cleanup lock.
*/
typedef struct xl_heap_prune
{
TransactionId snapshotConflictHorizon;
+ uint16 nplans;
uint16 nredirected;
uint16 ndead;
+ uint16 nunused;
bool isCatalogRel; /* to handle recovery conflict during logical
* decoding on standby */
- /* OFFSET NUMBERS are in the block reference 0 */
+ /*
+ * OFFSET NUMBERS and freeze plans are in the block reference 0 in the
+ * following order:
+ *
+ * * xl_heap_freeze_plan plans[nplans];
+ * * OffsetNumber redirected[2 * nredirected];
+ * * OffsetNumber nowdead[ndead];
+ * * OffsetNumber nowunused[nunused];
+ * * OffsetNumber frz_offsets[...];
+ */
} xl_heap_prune;
#define SizeOfHeapPrune (offsetof(xl_heap_prune, isCatalogRel) + sizeof(bool))
--
2.40.1
--racicctn4wry6xe5
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0013-Set-hastup-in-heap_page_prune.patch"
^ permalink raw reply [nested|flat] 15+ messages in thread
* [PATCH v4 13/19] Merge prune and freeze records
@ 2024-01-07 22:55 Melanie Plageman <[email protected]>
0 siblings, 0 replies; 15+ messages in thread
From: Melanie Plageman @ 2024-01-07 22:55 UTC (permalink / raw)
Eliminate xl_heap_freeze and XLOG_HEAP2_FREEZE record. When vacuum
freezes tuples, the information needed to replay those changes is
now recorded in the xl_heap_prune record.
When both pruning and freezing is done, this means a single, combined
WAL record is emitted for both operations. This will reduce the number
of WAL records emitted.
When there are only tuples to freeze present, we can avoid taking a full
cleanup lock when replaying the record.
The XLOG_HEAP2_PRUNE record is now bigger than it was previously and
bigger than the XLOG_HEAP2_FREEZE record. A future commit will
streamline the record.
---
src/backend/access/heap/heapam.c | 146 ++++------
src/backend/access/heap/pruneheap.c | 326 ++++++++++++-----------
src/backend/access/rmgrdesc/heapdesc.c | 95 ++++---
src/backend/replication/logical/decode.c | 1 -
src/include/access/heapam_xlog.h | 97 ++++---
5 files changed, 318 insertions(+), 347 deletions(-)
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index e47b56e7856..532868039d5 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -8706,8 +8706,6 @@ ExtractReplicaIdentity(Relation relation, HeapTuple tp, bool key_required,
/*
* Handles XLOG_HEAP2_PRUNE record type.
- *
- * Acquires a full cleanup lock.
*/
static void
heap_xlog_prune(XLogReaderState *record)
@@ -8718,12 +8716,22 @@ heap_xlog_prune(XLogReaderState *record)
RelFileLocator rlocator;
BlockNumber blkno;
XLogRedoAction action;
+ bool get_cleanup_lock;
XLogRecGetBlockTag(record, 0, &rlocator, NULL, &blkno);
/*
- * We're about to remove tuples. In Hot Standby mode, ensure that there's
- * no queries running for which the removed tuples are still visible.
+ * If there are dead, redirected, or unused items set unused by
+ * heap_page_prune_and_freeze(), heap_page_prune_execute() will call
+ * PageRepairFragementation() which expects a full cleanup lock.
+ */
+ get_cleanup_lock = xlrec->nredirected > 0 ||
+ xlrec->ndead > 0 || xlrec->nunused > 0;
+
+ /*
+ * We are either about to remove tuples or freeze them. In Hot Standby
+ * mode, ensure that there's no queries running for which any removed
+ * tuples are still visible or which consider the frozen xids as running.
*/
if (InHotStandby)
ResolveRecoveryConflictWithSnapshot(xlrec->snapshotConflictHorizon,
@@ -8731,38 +8739,69 @@ heap_xlog_prune(XLogReaderState *record)
rlocator);
/*
- * If we have a full-page image, restore it (using a cleanup lock) and
- * we're done.
+ * If we have a full-page image, restore it and we're done.
*/
- action = XLogReadBufferForRedoExtended(record, 0, RBM_NORMAL, true,
- &buffer);
+ action = XLogReadBufferForRedoExtended(record, 0, RBM_NORMAL,
+ get_cleanup_lock, &buffer);
+
if (action == BLK_NEEDS_REDO)
{
Page page = (Page) BufferGetPage(buffer);
- OffsetNumber *end;
OffsetNumber *redirected;
OffsetNumber *nowdead;
OffsetNumber *nowunused;
int nredirected;
int ndead;
int nunused;
+ int nplans;
Size datalen;
+ xl_heap_freeze_plan *plans;
+ OffsetNumber *frz_offsets;
+ int curoff = 0;
- redirected = (OffsetNumber *) XLogRecGetBlockData(record, 0, &datalen);
-
+ nplans = xlrec->nplans;
nredirected = xlrec->nredirected;
ndead = xlrec->ndead;
- end = (OffsetNumber *) ((char *) redirected + datalen);
+ nunused = xlrec->nunused;
+
+ plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, &datalen);
+ redirected = (OffsetNumber *) &plans[nplans];
nowdead = redirected + (nredirected * 2);
nowunused = nowdead + ndead;
- nunused = (end - nowunused);
- Assert(nunused >= 0);
+ frz_offsets = nowunused + nunused;
/* Update all line pointers per the record, and repair fragmentation */
- heap_page_prune_execute(buffer,
- redirected, nredirected,
- nowdead, ndead,
- nowunused, nunused);
+ if (nredirected > 0 || ndead > 0 || nunused > 0)
+ heap_page_prune_execute(buffer,
+ redirected, nredirected,
+ nowdead, ndead,
+ nowunused, nunused);
+
+ for (int p = 0; p < nplans; p++)
+ {
+ HeapTupleFreeze frz;
+
+ /*
+ * Convert freeze plan representation from WAL record into
+ * per-tuple format used by heap_execute_freeze_tuple
+ */
+ frz.xmax = plans[p].xmax;
+ frz.t_infomask2 = plans[p].t_infomask2;
+ frz.t_infomask = plans[p].t_infomask;
+ frz.frzflags = plans[p].frzflags;
+ frz.offset = InvalidOffsetNumber; /* unused, but be tidy */
+
+ for (int i = 0; i < plans[p].ntuples; i++)
+ {
+ OffsetNumber offset = frz_offsets[curoff++];
+ ItemId lp;
+ HeapTupleHeader tuple;
+
+ lp = PageGetItemId(page, offset);
+ tuple = (HeapTupleHeader) PageGetItem(page, lp);
+ heap_execute_freeze_tuple(tuple, &frz);
+ }
+ }
/*
* Note: we don't worry about updating the page's prunability hints.
@@ -9001,74 +9040,6 @@ heap_xlog_visible(XLogReaderState *record)
UnlockReleaseBuffer(vmbuffer);
}
-/*
- * Replay XLOG_HEAP2_FREEZE_PAGE records
- */
-static void
-heap_xlog_freeze_page(XLogReaderState *record)
-{
- XLogRecPtr lsn = record->EndRecPtr;
- xl_heap_freeze_page *xlrec = (xl_heap_freeze_page *) XLogRecGetData(record);
- Buffer buffer;
-
- /*
- * In Hot Standby mode, ensure that there's no queries running which still
- * consider the frozen xids as running.
- */
- if (InHotStandby)
- {
- RelFileLocator rlocator;
-
- XLogRecGetBlockTag(record, 0, &rlocator, NULL, NULL);
- ResolveRecoveryConflictWithSnapshot(xlrec->snapshotConflictHorizon,
- xlrec->isCatalogRel,
- rlocator);
- }
-
- if (XLogReadBufferForRedo(record, 0, &buffer) == BLK_NEEDS_REDO)
- {
- Page page = BufferGetPage(buffer);
- xl_heap_freeze_plan *plans;
- OffsetNumber *offsets;
- int curoff = 0;
-
- plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, NULL);
- offsets = (OffsetNumber *) ((char *) plans +
- (xlrec->nplans *
- sizeof(xl_heap_freeze_plan)));
- for (int p = 0; p < xlrec->nplans; p++)
- {
- HeapTupleFreeze frz;
-
- /*
- * Convert freeze plan representation from WAL record into
- * per-tuple format used by heap_execute_freeze_tuple
- */
- frz.xmax = plans[p].xmax;
- frz.t_infomask2 = plans[p].t_infomask2;
- frz.t_infomask = plans[p].t_infomask;
- frz.frzflags = plans[p].frzflags;
- frz.offset = InvalidOffsetNumber; /* unused, but be tidy */
-
- for (int i = 0; i < plans[p].ntuples; i++)
- {
- OffsetNumber offset = offsets[curoff++];
- ItemId lp;
- HeapTupleHeader tuple;
-
- lp = PageGetItemId(page, offset);
- tuple = (HeapTupleHeader) PageGetItem(page, lp);
- heap_execute_freeze_tuple(tuple, &frz);
- }
- }
-
- PageSetLSN(page, lsn);
- MarkBufferDirty(buffer);
- }
- if (BufferIsValid(buffer))
- UnlockReleaseBuffer(buffer);
-}
-
/*
* Given an "infobits" field from an XLog record, set the correct bits in the
* given infomask and infomask2 for the tuple touched by the record.
@@ -9975,9 +9946,6 @@ heap2_redo(XLogReaderState *record)
case XLOG_HEAP2_VACUUM:
heap_xlog_vacuum(record);
break;
- case XLOG_HEAP2_FREEZE_PAGE:
- heap_xlog_freeze_page(record);
- break;
case XLOG_HEAP2_VISIBLE:
heap_xlog_visible(record);
break;
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index 7bd479cfd4e..19b50931b90 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -79,6 +79,9 @@ static void heap_prune_record_dead_or_unused(PruneState *prstate, OffsetNumber o
static void heap_prune_record_unused(PruneState *prstate, OffsetNumber offnum);
static void page_verify_redirects(Page page);
+static void log_heap_prune_and_freeze(Relation relation, Buffer buffer,
+ PruneState *prstate, PruneFreezeResult *presult);
+
/*
* Optionally prune and repair fragmentation in the specified page.
@@ -247,9 +250,9 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
HeapTupleData tup;
bool do_freeze;
bool do_prune;
+ bool do_hint;
bool whole_page_freezable;
bool hint_bit_fpi;
- bool prune_fpi = false;
int64 fpi_before = pgWalUsage.wal_fpi;
/*
@@ -445,10 +448,9 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
/*
* If checksums are enabled, heap_prune_satisfies_vacuum() may have caused
- * an FPI to be emitted. Then reset fpi_before for no prune case.
+ * an FPI to be emitted.
*/
hint_bit_fpi = fpi_before != pgWalUsage.wal_fpi;
- fpi_before = pgWalUsage.wal_fpi;
/*
* For vacuum, if the whole page will become frozen, we consider
@@ -498,14 +500,18 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
prstate.ndead > 0 ||
prstate.nunused > 0;
+ /* Record number of newly-set-LP_DEAD items for caller */
+ presult->nnewlpdead = prstate.ndead;
+
/*
- * Only incur overhead of checking if we will do an FPI if we might use
- * the information.
+ * Even if we don't prune anything, if we found a new value for the
+ * pd_prune_xid field or the page was marked full, we will update the hint
+ * bit.
*/
- if (do_prune && pagefrz)
- prune_fpi = XLogCheckBufferNeedsBackup(buffer);
+ do_hint = ((PageHeader) page)->pd_prune_xid != prstate.new_prune_xid ||
+ PageIsFull(page);
- /* Is the whole page freezable? And is there something to freeze */
+ /* Is the whole page freezable? And is there something to freeze? */
whole_page_freezable = presult->all_visible_except_removable &&
presult->all_frozen;
@@ -520,43 +526,51 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
* opportunistic freeze heuristic must be improved; however, for now, try
* to approximate it.
*/
- do_freeze = pagefrz &&
- (pagefrz->freeze_required ||
- (whole_page_freezable && presult->nfrozen > 0 && (prune_fpi || hint_bit_fpi)));
+ do_freeze = false;
+ if (pagefrz)
+ {
+ if (pagefrz->freeze_required)
+ do_freeze = true;
+ else if (whole_page_freezable && presult->nfrozen > 0)
+ {
+ /*
+ * Freezing would make the page all-frozen. In this case, we will
+ * freeze if we have already emitted an FPI or will do so anyway.
+ * Be sure only to incur the overhead of checking if we will do an
+ * FPI if we may use that information.
+ */
+ if (hint_bit_fpi ||
+ ((do_prune || do_hint) && XLogCheckBufferNeedsBackup(buffer)))
+ {
+ do_freeze = true;
+ }
+ }
+ }
+ /*
+ * Validate the tuples we are considering freezing. We do this even if
+ * pruning and hint bit setting have not emitted an FPI so far because we
+ * still may emit an FPI while setting the page hint bit later. But we
+ * want to avoid doing the pre-freeze checks in a critical section.
+ */
if (do_freeze)
- {
heap_pre_freeze_checks(buffer, prstate.frozen, presult->nfrozen);
+ if (!do_freeze && (!pagefrz || !presult->all_frozen || presult->nfrozen > 0))
+ {
/*
- * We can use frz_conflict_horizon as our cutoff for conflicts when
- * the whole page is eligible to become all-frozen in the VM once
- * we're done with it. Otherwise we generate a conservative cutoff by
- * stepping back from OldestXmin.
+ * If we will neither freeze tuples on the page nor set the page all
+ * frozen in the visibility map, the page is not all-frozen and there
+ * will be no newly frozen tuples.
*/
- if (!(presult->all_visible_except_removable && presult->all_frozen))
- {
- /* Avoids false conflicts when hot_standby_feedback in use */
- presult->frz_conflict_horizon = pagefrz->cutoffs->OldestXmin;
- TransactionIdRetreat(presult->frz_conflict_horizon);
- }
+ presult->all_frozen = false;
+ presult->nfrozen = 0; /* avoid miscounts in instrumentation */
}
- /* Any error while applying the changes is critical */
START_CRIT_SECTION();
- /* Have we found any prunable items? */
- if (do_prune)
+ if (do_hint)
{
- /*
- * Apply the planned item changes, then repair page fragmentation, and
- * update the page's hint bit about whether it has free line pointers.
- */
- heap_page_prune_execute(buffer,
- prstate.redirected, prstate.nredirected,
- prstate.nowdead, prstate.ndead,
- prstate.nowunused, prstate.nunused);
-
/*
* Update the page's pd_prune_xid field to either zero, or the lowest
* XID of any soon-prunable tuple.
@@ -564,163 +578,159 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
((PageHeader) page)->pd_prune_xid = prstate.new_prune_xid;
/*
- * Also clear the "page is full" flag, since there's no point in
- * repeating the prune/defrag process until something else happens to
- * the page.
+ * Clear the "page is full" flag if it is set since there's no point
+ * in repeating the prune/defrag process until something else happens
+ * to the page.
*/
PageClearFull(page);
- MarkBufferDirty(buffer);
+ /*
+ * We only needed to update pd_prune_xid and clear the page-is-full
+ * hint bit, this is a non-WAL-logged hint. If we will also freeze or
+ * prune the page, we will mark the buffer dirty below.
+ */
+ if (!do_freeze && !do_prune)
+ MarkBufferDirtyHint(buffer, true);
+ }
+ if (do_prune || do_freeze)
+ {
/*
- * Emit a WAL XLOG_HEAP2_PRUNE record showing what we did
+ * Apply the planned item changes, then repair page fragmentation, and
+ * update the page's hint bit about whether it has free line pointers.
*/
- if (RelationNeedsWAL(relation))
+ if (do_prune)
{
- xl_heap_prune xlrec;
- XLogRecPtr recptr;
-
- xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
- xlrec.snapshotConflictHorizon = prstate.snapshotConflictHorizon;
- xlrec.nredirected = prstate.nredirected;
- xlrec.ndead = prstate.ndead;
-
- XLogBeginInsert();
- XLogRegisterData((char *) &xlrec, SizeOfHeapPrune);
-
- XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
+ heap_page_prune_execute(buffer,
+ prstate.redirected, prstate.nredirected,
+ prstate.nowdead, prstate.ndead,
+ prstate.nowunused, prstate.nunused);
+ }
+ if (do_freeze)
+ {
/*
- * The OffsetNumber arrays are not actually in the buffer, but we
- * pretend that they are. When XLogInsert stores the whole
- * buffer, the offset arrays need not be stored too.
+ * We can use frz_conflict_horizon as our cutoff for conflicts
+ * when the whole page is eligible to become all-frozen in the VM
+ * once we're done with it. Otherwise we generate a conservative
+ * cutoff by stepping back from OldestXmin. This avoids false
+ * conflicts when hot_standby_feedback is in use.
*/
- if (prstate.nredirected > 0)
- XLogRegisterBufData(0, (char *) prstate.redirected,
- prstate.nredirected *
- sizeof(OffsetNumber) * 2);
-
- if (prstate.ndead > 0)
- XLogRegisterBufData(0, (char *) prstate.nowdead,
- prstate.ndead * sizeof(OffsetNumber));
-
- if (prstate.nunused > 0)
- XLogRegisterBufData(0, (char *) prstate.nowunused,
- prstate.nunused * sizeof(OffsetNumber));
+ if (!(presult->all_visible_except_removable && presult->all_frozen))
+ {
+ presult->frz_conflict_horizon = pagefrz->cutoffs->OldestXmin;
+ TransactionIdRetreat(presult->frz_conflict_horizon);
+ }
+ heap_freeze_prepared_tuples(buffer, prstate.frozen, presult->nfrozen);
+ }
- recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
+ MarkBufferDirty(buffer);
- PageSetLSN(BufferGetPage(buffer), recptr);
- }
- }
- else
- {
/*
- * If we didn't prune anything, but have found a new value for the
- * pd_prune_xid field, update it and mark the buffer dirty. This is
- * treated as a non-WAL-logged hint.
- *
- * Also clear the "page is full" flag if it is set, since there's no
- * point in repeating the prune/defrag process until something else
- * happens to the page.
+ * Emit a WAL XLOG_HEAP2_PRUNE record showing what we did
*/
- if (((PageHeader) page)->pd_prune_xid != prstate.new_prune_xid ||
- PageIsFull(page))
- {
- ((PageHeader) page)->pd_prune_xid = prstate.new_prune_xid;
- PageClearFull(page);
- MarkBufferDirtyHint(buffer, true);
- }
+ if (RelationNeedsWAL(relation))
+ log_heap_prune_and_freeze(relation, buffer, &prstate, presult);
}
END_CRIT_SECTION();
- /* Record number of newly-set-LP_DEAD items for caller */
- presult->nnewlpdead = prstate.ndead;
-
- if (do_freeze)
+ /*
+ * If we froze tuples on the page, the caller can advance relfrozenxid and
+ * relminmxid to the values in pagefrz->FreezePageRelfrozenXid and
+ * pagefrz->FreezePageRelminMxid. Otherwise, it is only safe to advance to
+ * the values in pagefrz->NoFreezePage[RelfrozenXid|RelminMxid]
+ */
+ if (pagefrz)
{
- START_CRIT_SECTION();
+ if (presult->nfrozen > 0)
+ {
+ presult->new_relfrozenxid = pagefrz->FreezePageRelfrozenXid;
+ presult->new_relminmxid = pagefrz->FreezePageRelminMxid;
+ }
+ else
+ {
+ presult->new_relfrozenxid = pagefrz->NoFreezePageRelfrozenXid;
+ presult->new_relminmxid = pagefrz->NoFreezePageRelminMxid;
+ }
+ }
+}
- Assert(presult->nfrozen > 0);
- heap_freeze_prepared_tuples(buffer, prstate.frozen, presult->nfrozen);
+static void
+log_heap_prune_and_freeze(Relation relation, Buffer buffer,
+ PruneState *prstate, PruneFreezeResult *presult)
+{
+ xl_heap_prune xlrec;
+ XLogRecPtr recptr;
- MarkBufferDirty(buffer);
+ xl_heap_freeze_plan plans[MaxHeapTuplesPerPage];
+ OffsetNumber offsets[MaxHeapTuplesPerPage];
+ bool do_freeze = presult->nfrozen > 0;
- /* Now WAL-log freezing if necessary */
- if (RelationNeedsWAL(relation))
- {
- xl_heap_freeze_plan plans[MaxHeapTuplesPerPage];
- OffsetNumber offsets[MaxHeapTuplesPerPage];
- int nplans;
- xl_heap_freeze_page xlrec;
- XLogRecPtr recptr;
+ xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
+ xlrec.nredirected = prstate->nredirected;
+ xlrec.ndead = prstate->ndead;
+ xlrec.nunused = prstate->nunused;
+ xlrec.nplans = 0;
- /*
- * Prepare deduplicated representation for use in WAL record
- * Destructively sorts tuples array in-place.
- */
- nplans = heap_log_freeze_plan(prstate.frozen, presult->nfrozen, plans, offsets);
+ /*
+ * The snapshotConflictHorizon for the whole record should be the most
+ * conservative of all the horizons calculated for any of the possible
+ * modifications. If this record will prune tuples, any transactions on
+ * the standby older than the youngest xmax of the most recently removed
+ * tuple this record will prune will conflict. If this record will freeze
+ * tuples, any transactions on the standby with xids older than the
+ * youngest tuple this record will freeze will conflict.
+ */
+ if (do_freeze)
+ xlrec.snapshotConflictHorizon = Max(prstate->snapshotConflictHorizon,
+ presult->frz_conflict_horizon);
+ else
+ xlrec.snapshotConflictHorizon = prstate->snapshotConflictHorizon;
- xlrec.snapshotConflictHorizon = presult->frz_conflict_horizon;
- xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
- xlrec.nplans = nplans;
+ /*
+ * Prepare deduplicated representation for use in WAL record Destructively
+ * sorts tuples array in-place.
+ */
+ if (do_freeze)
+ xlrec.nplans = heap_log_freeze_plan(prstate->frozen,
+ presult->nfrozen, plans, offsets);
- XLogBeginInsert();
- XLogRegisterData((char *) &xlrec, SizeOfHeapFreezePage);
+ XLogBeginInsert();
+ XLogRegisterData((char *) &xlrec, SizeOfHeapPrune);
- /*
- * The freeze plan array and offset array are not actually in the
- * buffer, but pretend that they are. When XLogInsert stores the
- * whole buffer, the arrays need not be stored too.
- */
- XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
- XLogRegisterBufData(0, (char *) plans,
- nplans * sizeof(xl_heap_freeze_plan));
- XLogRegisterBufData(0, (char *) offsets,
- presult->nfrozen * sizeof(OffsetNumber));
+ XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
- recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_FREEZE_PAGE);
+ /*
+ * The OffsetNumber arrays are not actually in the buffer, but we pretend
+ * that they are. When XLogInsert stores the whole buffer, the offset
+ * arrays need not be stored too.
+ */
+ if (xlrec.nplans > 0)
+ XLogRegisterBufData(0, (char *) plans,
+ xlrec.nplans * sizeof(xl_heap_freeze_plan));
- PageSetLSN(page, recptr);
- }
+ if (prstate->nredirected > 0)
+ XLogRegisterBufData(0, (char *) prstate->redirected,
+ prstate->nredirected *
+ sizeof(OffsetNumber) * 2);
- END_CRIT_SECTION();
- }
- else if (!pagefrz || !presult->all_frozen || presult->nfrozen > 0)
- {
- /*
- * If we will neither freeze tuples on the page nor set the page all
- * frozen in the visibility map, the page is not all frozen and there
- * will be no newly frozen tuples.
- */
- presult->all_frozen = false;
- presult->nfrozen = 0; /* avoid miscounts in instrumentation */
- }
+ if (prstate->ndead > 0)
+ XLogRegisterBufData(0, (char *) prstate->nowdead,
+ prstate->ndead * sizeof(OffsetNumber));
- /* Caller won't update new_relfrozenxid and new_relminmxid */
- if (!pagefrz)
- return;
+ if (prstate->nunused > 0)
+ XLogRegisterBufData(0, (char *) prstate->nowunused,
+ prstate->nunused * sizeof(OffsetNumber));
+ if (xlrec.nplans > 0)
+ XLogRegisterBufData(0, (char *) offsets,
+ presult->nfrozen * sizeof(OffsetNumber));
- /*
- * If we will freeze tuples on the page or, even if we don't freeze tuples
- * on the page, if we will set the page all-frozen in the visibility map,
- * we can advance relfrozenxid and relminmxid to the values in
- * pagefrz->FreezePageRelfrozenXid and pagefrz->FreezePageRelminMxid.
- */
- if (presult->all_frozen || presult->nfrozen > 0)
- {
- presult->new_relfrozenxid = pagefrz->FreezePageRelfrozenXid;
- presult->new_relminmxid = pagefrz->FreezePageRelminMxid;
- }
- else
- {
- presult->new_relfrozenxid = pagefrz->NoFreezePageRelfrozenXid;
- presult->new_relminmxid = pagefrz->NoFreezePageRelminMxid;
- }
-}
+ recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
+ PageSetLSN(BufferGetPage(buffer), recptr);
+}
/*
* Perform visibility checks for heap pruning.
diff --git a/src/backend/access/rmgrdesc/heapdesc.c b/src/backend/access/rmgrdesc/heapdesc.c
index 36a3d83c8c2..9f0a0341d40 100644
--- a/src/backend/access/rmgrdesc/heapdesc.c
+++ b/src/backend/access/rmgrdesc/heapdesc.c
@@ -179,43 +179,67 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
{
xl_heap_prune *xlrec = (xl_heap_prune *) rec;
- appendStringInfo(buf, "snapshotConflictHorizon: %u, nredirected: %u, ndead: %u, isCatalogRel: %c",
+ appendStringInfo(buf, "snapshotConflictHorizon: %u, isCatalogRel: %c",
xlrec->snapshotConflictHorizon,
- xlrec->nredirected,
- xlrec->ndead,
xlrec->isCatalogRel ? 'T' : 'F');
if (XLogRecHasBlockData(record, 0))
{
- OffsetNumber *end;
OffsetNumber *redirected;
OffsetNumber *nowdead;
OffsetNumber *nowunused;
int nredirected;
+ int ndead;
int nunused;
+ int nplans;
Size datalen;
+ xl_heap_freeze_plan *plans;
+ OffsetNumber *frz_offsets;
- redirected = (OffsetNumber *) XLogRecGetBlockData(record, 0,
- &datalen);
-
+ nplans = xlrec->nplans;
nredirected = xlrec->nredirected;
- end = (OffsetNumber *) ((char *) redirected + datalen);
- nowdead = redirected + (nredirected * 2);
- nowunused = nowdead + xlrec->ndead;
- nunused = (end - nowunused);
- Assert(nunused >= 0);
+ ndead = xlrec->ndead;
+ nunused = xlrec->nunused;
- appendStringInfo(buf, ", nunused: %d", nunused);
-
- appendStringInfoString(buf, ", redirected:");
- array_desc(buf, redirected, sizeof(OffsetNumber) * 2,
- nredirected, &redirect_elem_desc, NULL);
- appendStringInfoString(buf, ", dead:");
- array_desc(buf, nowdead, sizeof(OffsetNumber), xlrec->ndead,
- &offset_elem_desc, NULL);
- appendStringInfoString(buf, ", unused:");
- array_desc(buf, nowunused, sizeof(OffsetNumber), nunused,
- &offset_elem_desc, NULL);
+ plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, &datalen);
+ redirected = (OffsetNumber *) &plans[nplans];
+ nowdead = redirected + (nredirected * 2);
+ nowunused = nowdead + ndead;
+ frz_offsets = nowunused + nunused;
+
+ appendStringInfo(buf, ", nredirected: %u, ndead: %u, nunused: %u, nplans: %u,",
+ nredirected,
+ ndead,
+ nunused,
+ nplans);
+
+ if (nredirected > 0)
+ {
+ appendStringInfoString(buf, ", redirected:");
+ array_desc(buf, redirected, sizeof(OffsetNumber) * 2,
+ nredirected, &redirect_elem_desc, NULL);
+ }
+
+ if (ndead > 0)
+ {
+ appendStringInfoString(buf, ", dead:");
+ array_desc(buf, nowdead, sizeof(OffsetNumber), ndead,
+ &offset_elem_desc, NULL);
+ }
+
+ if (nunused > 0)
+ {
+ appendStringInfoString(buf, ", unused:");
+ array_desc(buf, nowunused, sizeof(OffsetNumber), nunused,
+ &offset_elem_desc, NULL);
+ }
+
+ if (nplans > 0)
+ {
+ appendStringInfoString(buf, ", plans:");
+ array_desc(buf, plans, sizeof(xl_heap_freeze_plan), nplans,
+ &plan_elem_desc, &frz_offsets);
+ }
}
}
else if (info == XLOG_HEAP2_VACUUM)
@@ -235,28 +259,6 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
&offset_elem_desc, NULL);
}
}
- else if (info == XLOG_HEAP2_FREEZE_PAGE)
- {
- xl_heap_freeze_page *xlrec = (xl_heap_freeze_page *) rec;
-
- appendStringInfo(buf, "snapshotConflictHorizon: %u, nplans: %u, isCatalogRel: %c",
- xlrec->snapshotConflictHorizon, xlrec->nplans,
- xlrec->isCatalogRel ? 'T' : 'F');
-
- if (XLogRecHasBlockData(record, 0))
- {
- xl_heap_freeze_plan *plans;
- OffsetNumber *offsets;
-
- plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, NULL);
- offsets = (OffsetNumber *) ((char *) plans +
- (xlrec->nplans *
- sizeof(xl_heap_freeze_plan)));
- appendStringInfoString(buf, ", plans:");
- array_desc(buf, plans, sizeof(xl_heap_freeze_plan), xlrec->nplans,
- &plan_elem_desc, &offsets);
- }
- }
else if (info == XLOG_HEAP2_VISIBLE)
{
xl_heap_visible *xlrec = (xl_heap_visible *) rec;
@@ -361,9 +363,6 @@ heap2_identify(uint8 info)
case XLOG_HEAP2_VACUUM:
id = "VACUUM";
break;
- case XLOG_HEAP2_FREEZE_PAGE:
- id = "FREEZE_PAGE";
- break;
case XLOG_HEAP2_VISIBLE:
id = "VISIBLE";
break;
diff --git a/src/backend/replication/logical/decode.c b/src/backend/replication/logical/decode.c
index e5ab7b78b78..f77051572fd 100644
--- a/src/backend/replication/logical/decode.c
+++ b/src/backend/replication/logical/decode.c
@@ -445,7 +445,6 @@ heap2_decode(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
* Everything else here is just low level physical stuff we're not
* interested in.
*/
- case XLOG_HEAP2_FREEZE_PAGE:
case XLOG_HEAP2_PRUNE:
case XLOG_HEAP2_VACUUM:
case XLOG_HEAP2_VISIBLE:
diff --git a/src/include/access/heapam_xlog.h b/src/include/access/heapam_xlog.h
index 6488dad5e64..fe4a8ff0620 100644
--- a/src/include/access/heapam_xlog.h
+++ b/src/include/access/heapam_xlog.h
@@ -53,11 +53,10 @@
#define XLOG_HEAP2_REWRITE 0x00
#define XLOG_HEAP2_PRUNE 0x10
#define XLOG_HEAP2_VACUUM 0x20
-#define XLOG_HEAP2_FREEZE_PAGE 0x30
-#define XLOG_HEAP2_VISIBLE 0x40
-#define XLOG_HEAP2_MULTI_INSERT 0x50
-#define XLOG_HEAP2_LOCK_UPDATED 0x60
-#define XLOG_HEAP2_NEW_CID 0x70
+#define XLOG_HEAP2_VISIBLE 0x30
+#define XLOG_HEAP2_MULTI_INSERT 0x40
+#define XLOG_HEAP2_LOCK_UPDATED 0x50
+#define XLOG_HEAP2_NEW_CID 0x60
/*
* xl_heap_insert/xl_heap_multi_insert flag values, 8 bits are available.
@@ -226,28 +225,65 @@ typedef struct xl_heap_update
#define SizeOfHeapUpdate (offsetof(xl_heap_update, new_offnum) + sizeof(OffsetNumber))
+/*
+ * This struct represents a 'freeze plan', which describes how to freeze a
+ * group of one or more heap tuples (appears in xl_heap_prune record)
+ */
+/* 0x01 was XLH_FREEZE_XMIN */
+#define XLH_FREEZE_XVAC 0x02
+#define XLH_INVALID_XVAC 0x04
+
+typedef struct xl_heap_freeze_plan
+{
+ TransactionId xmax;
+ uint16 t_infomask2;
+ uint16 t_infomask;
+ uint8 frzflags;
+
+ /* Length of individual page offset numbers array for this plan */
+ uint16 ntuples;
+} xl_heap_freeze_plan;
+
+/*
+ * As of Postgres 17, XLOG_HEAP2_PRUNE records replace
+ * XLOG_HEAP2_FREEZE_PAGE records.
+ */
+
/*
* This is what we need to know about page pruning (both during VACUUM and
* during opportunistic pruning)
*
* The array of OffsetNumbers following the fixed part of the record contains:
+ * * for each freeze plan: the freeze plan
* * for each redirected item: the item offset, then the offset redirected to
* * for each now-dead item: the item offset
* * for each now-unused item: the item offset
- * The total number of OffsetNumbers is therefore 2*nredirected+ndead+nunused.
- * Note that nunused is not explicitly stored, but may be found by reference
- * to the total record length.
+ * * for each tuple frozen by the freeze plans: the offset of the item corresponding to that tuple
+ * The total number of OffsetNumbers is therefore
+ * (2*nredirected) + ndead + nunused + (sum[plan.ntuples for plan in plans])
*
- * Acquires a full cleanup lock.
+ * Acquires a full cleanup lock if heap_page_prune_execute() must be called
*/
typedef struct xl_heap_prune
{
TransactionId snapshotConflictHorizon;
+ uint16 nplans;
uint16 nredirected;
uint16 ndead;
+ uint16 nunused;
bool isCatalogRel; /* to handle recovery conflict during logical
* decoding on standby */
- /* OFFSET NUMBERS are in the block reference 0 */
+ /*--------------------------------------------------------------------
+ * OFFSET NUMBERS and freeze plans are in the block reference 0 in the
+ * following order:
+ *
+ * * xl_heap_freeze_plan plans[nplans];
+ * * OffsetNumber redirected[2 * nredirected];
+ * * OffsetNumber nowdead[ndead];
+ * * OffsetNumber nowunused[nunused];
+ * * OffsetNumber frz_offsets[...];
+ *--------------------------------------------------------------------
+ */
} xl_heap_prune;
#define SizeOfHeapPrune (offsetof(xl_heap_prune, isCatalogRel) + sizeof(bool))
@@ -315,47 +351,6 @@ typedef struct xl_heap_inplace
#define SizeOfHeapInplace (offsetof(xl_heap_inplace, offnum) + sizeof(OffsetNumber))
-/*
- * This struct represents a 'freeze plan', which describes how to freeze a
- * group of one or more heap tuples (appears in xl_heap_freeze_page record)
- */
-/* 0x01 was XLH_FREEZE_XMIN */
-#define XLH_FREEZE_XVAC 0x02
-#define XLH_INVALID_XVAC 0x04
-
-typedef struct xl_heap_freeze_plan
-{
- TransactionId xmax;
- uint16 t_infomask2;
- uint16 t_infomask;
- uint8 frzflags;
-
- /* Length of individual page offset numbers array for this plan */
- uint16 ntuples;
-} xl_heap_freeze_plan;
-
-/*
- * This is what we need to know about a block being frozen during vacuum
- *
- * Backup block 0's data contains an array of xl_heap_freeze_plan structs
- * (with nplans elements), followed by one or more page offset number arrays.
- * Each such page offset number array corresponds to a single freeze plan
- * (REDO routine freezes corresponding heap tuples using freeze plan).
- */
-typedef struct xl_heap_freeze_page
-{
- TransactionId snapshotConflictHorizon;
- uint16 nplans;
- bool isCatalogRel; /* to handle recovery conflict during logical
- * decoding on standby */
-
- /*
- * In payload of blk 0 : FREEZE PLANS and OFFSET NUMBER ARRAY
- */
-} xl_heap_freeze_page;
-
-#define SizeOfHeapFreezePage (offsetof(xl_heap_freeze_page, isCatalogRel) + sizeof(bool))
-
/*
* This is what we need to know about setting a visibility map bit
*
--
2.40.1
--tez7m2a73jtztiij
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0014-Vacuum-second-pass-emits-XLOG_HEAP2_PRUNE-record.patch"
^ permalink raw reply [nested|flat] 15+ messages in thread
* [PATCH v3 12/17] Merge prune and freeze records
@ 2024-01-07 22:55 Melanie Plageman <[email protected]>
0 siblings, 0 replies; 15+ messages in thread
From: Melanie Plageman @ 2024-01-07 22:55 UTC (permalink / raw)
When there are both tuples to prune and freeze on a page, emit a single,
combined prune record containing the offsets for pruning and the freeze
plans and offsets for freezing. This will reduce the number of WAL
records emitted.
---
src/backend/access/heap/heapam.c | 42 ++++++++++++--
src/backend/access/heap/pruneheap.c | 85 +++++++++++++----------------
src/include/access/heapam_xlog.h | 20 +++++--
3 files changed, 90 insertions(+), 57 deletions(-)
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index a3691584c55..a8f35eba3c9 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -8803,24 +8803,28 @@ heap_xlog_prune(XLogReaderState *record)
if (action == BLK_NEEDS_REDO)
{
Page page = (Page) BufferGetPage(buffer);
- OffsetNumber *end;
OffsetNumber *redirected;
OffsetNumber *nowdead;
OffsetNumber *nowunused;
int nredirected;
int ndead;
int nunused;
+ int nplans;
Size datalen;
+ xl_heap_freeze_plan *plans;
+ OffsetNumber *frz_offsets;
+ int curoff = 0;
- redirected = (OffsetNumber *) XLogRecGetBlockData(record, 0, &datalen);
-
+ nplans = xlrec->nplans;
nredirected = xlrec->nredirected;
ndead = xlrec->ndead;
- end = (OffsetNumber *) ((char *) redirected + datalen);
+ nunused = xlrec->nunused;
+
+ plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, &datalen);
+ redirected = (OffsetNumber *) &plans[nplans];
nowdead = redirected + (nredirected * 2);
nowunused = nowdead + ndead;
- nunused = (end - nowunused);
- Assert(nunused >= 0);
+ frz_offsets = nowunused + nunused;
/* Update all line pointers per the record, and repair fragmentation */
heap_page_prune_execute(buffer,
@@ -8828,6 +8832,32 @@ heap_xlog_prune(XLogReaderState *record)
nowdead, ndead,
nowunused, nunused);
+ for (int p = 0; p < nplans; p++)
+ {
+ HeapTupleFreeze frz;
+
+ /*
+ * Convert freeze plan representation from WAL record into
+ * per-tuple format used by heap_execute_freeze_tuple
+ */
+ frz.xmax = plans[p].xmax;
+ frz.t_infomask2 = plans[p].t_infomask2;
+ frz.t_infomask = plans[p].t_infomask;
+ frz.frzflags = plans[p].frzflags;
+ frz.offset = InvalidOffsetNumber; /* unused, but be tidy */
+
+ for (int i = 0; i < plans[p].ntuples; i++)
+ {
+ OffsetNumber offset = frz_offsets[curoff++];
+ ItemId lp;
+ HeapTupleHeader tuple;
+
+ lp = PageGetItemId(page, offset);
+ tuple = (HeapTupleHeader) PageGetItem(page, lp);
+ heap_execute_freeze_tuple(tuple, &frz);
+ }
+ }
+
/*
* Note: we don't worry about updating the page's prunability hints.
* At worst this will cause an extra prune cycle to occur soon.
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index d77270ad0d6..994cf75c54e 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -619,6 +619,9 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
*/
PageClearFull(page);
+ if (do_freeze)
+ heap_freeze_prepared_tuples(buffer, frozen, presult->nfrozen);
+
MarkBufferDirty(buffer);
/*
@@ -629,10 +632,37 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
xl_heap_prune xlrec;
XLogRecPtr recptr;
+ xl_heap_freeze_plan plans[MaxHeapTuplesPerPage];
+ OffsetNumber offsets[MaxHeapTuplesPerPage];
+
xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
- xlrec.snapshotConflictHorizon = prstate.snapshotConflictHorizon;
xlrec.nredirected = prstate.nredirected;
xlrec.ndead = prstate.ndead;
+ xlrec.nunused = prstate.nunused;
+ xlrec.nplans = 0;
+
+ /*
+ * The snapshotConflictHorizon for the whole record should be the most
+ * conservative of all the horizons calculated for any of the possible
+ * modifications. If this record will prune tuples, any transactions
+ * on the standby older than the youngest xmax of the most recently
+ * removed tuple this record will prune will conflict. If this record
+ * will freeze tuples, any transactions on the standby with xids older
+ * than the youngest tuple this record will freeze will conflict.
+ */
+ if (do_freeze)
+ xlrec.snapshotConflictHorizon = Max(prstate.snapshotConflictHorizon,
+ frz_conflict_horizon);
+ else
+ xlrec.snapshotConflictHorizon = prstate.snapshotConflictHorizon;
+
+ /*
+ * Prepare deduplicated representation for use in WAL record
+ * Destructively sorts tuples array in-place.
+ */
+ if (do_freeze)
+ xlrec.nplans = heap_log_freeze_plan(frozen,
+ presult->nfrozen, plans, offsets);
XLogBeginInsert();
XLogRegisterData((char *) &xlrec, SizeOfHeapPrune);
@@ -644,6 +674,10 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
* pretend that they are. When XLogInsert stores the whole buffer,
* the offset arrays need not be stored too.
*/
+ if (xlrec.nplans > 0)
+ XLogRegisterBufData(0, (char *) plans,
+ xlrec.nplans * sizeof(xl_heap_freeze_plan));
+
if (prstate.nredirected > 0)
XLogRegisterBufData(0, (char *) prstate.redirected,
prstate.nredirected *
@@ -657,56 +691,13 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
XLogRegisterBufData(0, (char *) prstate.nowunused,
prstate.nunused * sizeof(OffsetNumber));
- recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
-
- PageSetLSN(BufferGetPage(buffer), recptr);
- }
-
- if (do_freeze)
- {
- Assert(presult->nfrozen > 0);
-
- heap_freeze_prepared_tuples(buffer, frozen, presult->nfrozen);
-
- MarkBufferDirty(buffer);
-
- /* Now WAL-log freezing if necessary */
- if (RelationNeedsWAL(relation))
- {
- xl_heap_freeze_plan plans[MaxHeapTuplesPerPage];
- OffsetNumber offsets[MaxHeapTuplesPerPage];
- int nplans;
- xl_heap_freeze_page xlrec;
- XLogRecPtr recptr;
-
- /*
- * Prepare deduplicated representation for use in WAL record
- * Destructively sorts tuples array in-place.
- */
- nplans = heap_log_freeze_plan(frozen, presult->nfrozen, plans, offsets);
-
- xlrec.snapshotConflictHorizon = frz_conflict_horizon;
- xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
- xlrec.nplans = nplans;
-
- XLogBeginInsert();
- XLogRegisterData((char *) &xlrec, SizeOfHeapFreezePage);
-
- /*
- * The freeze plan array and offset array are not actually in the
- * buffer, but pretend that they are. When XLogInsert stores the
- * whole buffer, the arrays need not be stored too.
- */
- XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
- XLogRegisterBufData(0, (char *) plans,
- nplans * sizeof(xl_heap_freeze_plan));
+ if (xlrec.nplans > 0)
XLogRegisterBufData(0, (char *) offsets,
presult->nfrozen * sizeof(OffsetNumber));
- recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_FREEZE_PAGE);
+ recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
- PageSetLSN(page, recptr);
- }
+ PageSetLSN(BufferGetPage(buffer), recptr);
}
END_CRIT_SECTION();
diff --git a/src/include/access/heapam_xlog.h b/src/include/access/heapam_xlog.h
index 6488dad5e64..22f236bb52a 100644
--- a/src/include/access/heapam_xlog.h
+++ b/src/include/access/heapam_xlog.h
@@ -231,23 +231,35 @@ typedef struct xl_heap_update
* during opportunistic pruning)
*
* The array of OffsetNumbers following the fixed part of the record contains:
+ * * for each freeze plan: the freeze plan
* * for each redirected item: the item offset, then the offset redirected to
* * for each now-dead item: the item offset
* * for each now-unused item: the item offset
- * The total number of OffsetNumbers is therefore 2*nredirected+ndead+nunused.
- * Note that nunused is not explicitly stored, but may be found by reference
- * to the total record length.
+ * * for each tuple frozen by the freeze plans: the offset of the item corresponding to that tuple
+ * The total number of OffsetNumbers is therefore
+ * (2*nredirected) + ndead + nunused + (sum[plan.ntuples for plan in plans])
*
* Acquires a full cleanup lock.
*/
typedef struct xl_heap_prune
{
TransactionId snapshotConflictHorizon;
+ uint16 nplans;
uint16 nredirected;
uint16 ndead;
+ uint16 nunused;
bool isCatalogRel; /* to handle recovery conflict during logical
* decoding on standby */
- /* OFFSET NUMBERS are in the block reference 0 */
+ /*
+ * OFFSET NUMBERS and freeze plans are in the block reference 0 in the
+ * following order:
+ *
+ * * xl_heap_freeze_plan plans[nplans];
+ * * OffsetNumber redirected[2 * nredirected];
+ * * OffsetNumber nowdead[ndead];
+ * * OffsetNumber nowunused[nunused];
+ * * OffsetNumber frz_offsets[...];
+ */
} xl_heap_prune;
#define SizeOfHeapPrune (offsetof(xl_heap_prune, isCatalogRel) + sizeof(bool))
--
2.40.1
--racicctn4wry6xe5
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0013-Set-hastup-in-heap_page_prune.patch"
^ permalink raw reply [nested|flat] 15+ messages in thread
* [PATCH v4 13/19] Merge prune and freeze records
@ 2024-01-07 22:55 Melanie Plageman <[email protected]>
0 siblings, 0 replies; 15+ messages in thread
From: Melanie Plageman @ 2024-01-07 22:55 UTC (permalink / raw)
Eliminate xl_heap_freeze and XLOG_HEAP2_FREEZE record. When vacuum
freezes tuples, the information needed to replay those changes is
now recorded in the xl_heap_prune record.
When both pruning and freezing is done, this means a single, combined
WAL record is emitted for both operations. This will reduce the number
of WAL records emitted.
When there are only tuples to freeze present, we can avoid taking a full
cleanup lock when replaying the record.
The XLOG_HEAP2_PRUNE record is now bigger than it was previously and
bigger than the XLOG_HEAP2_FREEZE record. A future commit will
streamline the record.
---
src/backend/access/heap/heapam.c | 146 ++++------
src/backend/access/heap/pruneheap.c | 326 ++++++++++++-----------
src/backend/access/rmgrdesc/heapdesc.c | 95 ++++---
src/backend/replication/logical/decode.c | 1 -
src/include/access/heapam_xlog.h | 97 ++++---
5 files changed, 318 insertions(+), 347 deletions(-)
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index e47b56e7856..532868039d5 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -8706,8 +8706,6 @@ ExtractReplicaIdentity(Relation relation, HeapTuple tp, bool key_required,
/*
* Handles XLOG_HEAP2_PRUNE record type.
- *
- * Acquires a full cleanup lock.
*/
static void
heap_xlog_prune(XLogReaderState *record)
@@ -8718,12 +8716,22 @@ heap_xlog_prune(XLogReaderState *record)
RelFileLocator rlocator;
BlockNumber blkno;
XLogRedoAction action;
+ bool get_cleanup_lock;
XLogRecGetBlockTag(record, 0, &rlocator, NULL, &blkno);
/*
- * We're about to remove tuples. In Hot Standby mode, ensure that there's
- * no queries running for which the removed tuples are still visible.
+ * If there are dead, redirected, or unused items set unused by
+ * heap_page_prune_and_freeze(), heap_page_prune_execute() will call
+ * PageRepairFragementation() which expects a full cleanup lock.
+ */
+ get_cleanup_lock = xlrec->nredirected > 0 ||
+ xlrec->ndead > 0 || xlrec->nunused > 0;
+
+ /*
+ * We are either about to remove tuples or freeze them. In Hot Standby
+ * mode, ensure that there's no queries running for which any removed
+ * tuples are still visible or which consider the frozen xids as running.
*/
if (InHotStandby)
ResolveRecoveryConflictWithSnapshot(xlrec->snapshotConflictHorizon,
@@ -8731,38 +8739,69 @@ heap_xlog_prune(XLogReaderState *record)
rlocator);
/*
- * If we have a full-page image, restore it (using a cleanup lock) and
- * we're done.
+ * If we have a full-page image, restore it and we're done.
*/
- action = XLogReadBufferForRedoExtended(record, 0, RBM_NORMAL, true,
- &buffer);
+ action = XLogReadBufferForRedoExtended(record, 0, RBM_NORMAL,
+ get_cleanup_lock, &buffer);
+
if (action == BLK_NEEDS_REDO)
{
Page page = (Page) BufferGetPage(buffer);
- OffsetNumber *end;
OffsetNumber *redirected;
OffsetNumber *nowdead;
OffsetNumber *nowunused;
int nredirected;
int ndead;
int nunused;
+ int nplans;
Size datalen;
+ xl_heap_freeze_plan *plans;
+ OffsetNumber *frz_offsets;
+ int curoff = 0;
- redirected = (OffsetNumber *) XLogRecGetBlockData(record, 0, &datalen);
-
+ nplans = xlrec->nplans;
nredirected = xlrec->nredirected;
ndead = xlrec->ndead;
- end = (OffsetNumber *) ((char *) redirected + datalen);
+ nunused = xlrec->nunused;
+
+ plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, &datalen);
+ redirected = (OffsetNumber *) &plans[nplans];
nowdead = redirected + (nredirected * 2);
nowunused = nowdead + ndead;
- nunused = (end - nowunused);
- Assert(nunused >= 0);
+ frz_offsets = nowunused + nunused;
/* Update all line pointers per the record, and repair fragmentation */
- heap_page_prune_execute(buffer,
- redirected, nredirected,
- nowdead, ndead,
- nowunused, nunused);
+ if (nredirected > 0 || ndead > 0 || nunused > 0)
+ heap_page_prune_execute(buffer,
+ redirected, nredirected,
+ nowdead, ndead,
+ nowunused, nunused);
+
+ for (int p = 0; p < nplans; p++)
+ {
+ HeapTupleFreeze frz;
+
+ /*
+ * Convert freeze plan representation from WAL record into
+ * per-tuple format used by heap_execute_freeze_tuple
+ */
+ frz.xmax = plans[p].xmax;
+ frz.t_infomask2 = plans[p].t_infomask2;
+ frz.t_infomask = plans[p].t_infomask;
+ frz.frzflags = plans[p].frzflags;
+ frz.offset = InvalidOffsetNumber; /* unused, but be tidy */
+
+ for (int i = 0; i < plans[p].ntuples; i++)
+ {
+ OffsetNumber offset = frz_offsets[curoff++];
+ ItemId lp;
+ HeapTupleHeader tuple;
+
+ lp = PageGetItemId(page, offset);
+ tuple = (HeapTupleHeader) PageGetItem(page, lp);
+ heap_execute_freeze_tuple(tuple, &frz);
+ }
+ }
/*
* Note: we don't worry about updating the page's prunability hints.
@@ -9001,74 +9040,6 @@ heap_xlog_visible(XLogReaderState *record)
UnlockReleaseBuffer(vmbuffer);
}
-/*
- * Replay XLOG_HEAP2_FREEZE_PAGE records
- */
-static void
-heap_xlog_freeze_page(XLogReaderState *record)
-{
- XLogRecPtr lsn = record->EndRecPtr;
- xl_heap_freeze_page *xlrec = (xl_heap_freeze_page *) XLogRecGetData(record);
- Buffer buffer;
-
- /*
- * In Hot Standby mode, ensure that there's no queries running which still
- * consider the frozen xids as running.
- */
- if (InHotStandby)
- {
- RelFileLocator rlocator;
-
- XLogRecGetBlockTag(record, 0, &rlocator, NULL, NULL);
- ResolveRecoveryConflictWithSnapshot(xlrec->snapshotConflictHorizon,
- xlrec->isCatalogRel,
- rlocator);
- }
-
- if (XLogReadBufferForRedo(record, 0, &buffer) == BLK_NEEDS_REDO)
- {
- Page page = BufferGetPage(buffer);
- xl_heap_freeze_plan *plans;
- OffsetNumber *offsets;
- int curoff = 0;
-
- plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, NULL);
- offsets = (OffsetNumber *) ((char *) plans +
- (xlrec->nplans *
- sizeof(xl_heap_freeze_plan)));
- for (int p = 0; p < xlrec->nplans; p++)
- {
- HeapTupleFreeze frz;
-
- /*
- * Convert freeze plan representation from WAL record into
- * per-tuple format used by heap_execute_freeze_tuple
- */
- frz.xmax = plans[p].xmax;
- frz.t_infomask2 = plans[p].t_infomask2;
- frz.t_infomask = plans[p].t_infomask;
- frz.frzflags = plans[p].frzflags;
- frz.offset = InvalidOffsetNumber; /* unused, but be tidy */
-
- for (int i = 0; i < plans[p].ntuples; i++)
- {
- OffsetNumber offset = offsets[curoff++];
- ItemId lp;
- HeapTupleHeader tuple;
-
- lp = PageGetItemId(page, offset);
- tuple = (HeapTupleHeader) PageGetItem(page, lp);
- heap_execute_freeze_tuple(tuple, &frz);
- }
- }
-
- PageSetLSN(page, lsn);
- MarkBufferDirty(buffer);
- }
- if (BufferIsValid(buffer))
- UnlockReleaseBuffer(buffer);
-}
-
/*
* Given an "infobits" field from an XLog record, set the correct bits in the
* given infomask and infomask2 for the tuple touched by the record.
@@ -9975,9 +9946,6 @@ heap2_redo(XLogReaderState *record)
case XLOG_HEAP2_VACUUM:
heap_xlog_vacuum(record);
break;
- case XLOG_HEAP2_FREEZE_PAGE:
- heap_xlog_freeze_page(record);
- break;
case XLOG_HEAP2_VISIBLE:
heap_xlog_visible(record);
break;
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index 7bd479cfd4e..19b50931b90 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -79,6 +79,9 @@ static void heap_prune_record_dead_or_unused(PruneState *prstate, OffsetNumber o
static void heap_prune_record_unused(PruneState *prstate, OffsetNumber offnum);
static void page_verify_redirects(Page page);
+static void log_heap_prune_and_freeze(Relation relation, Buffer buffer,
+ PruneState *prstate, PruneFreezeResult *presult);
+
/*
* Optionally prune and repair fragmentation in the specified page.
@@ -247,9 +250,9 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
HeapTupleData tup;
bool do_freeze;
bool do_prune;
+ bool do_hint;
bool whole_page_freezable;
bool hint_bit_fpi;
- bool prune_fpi = false;
int64 fpi_before = pgWalUsage.wal_fpi;
/*
@@ -445,10 +448,9 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
/*
* If checksums are enabled, heap_prune_satisfies_vacuum() may have caused
- * an FPI to be emitted. Then reset fpi_before for no prune case.
+ * an FPI to be emitted.
*/
hint_bit_fpi = fpi_before != pgWalUsage.wal_fpi;
- fpi_before = pgWalUsage.wal_fpi;
/*
* For vacuum, if the whole page will become frozen, we consider
@@ -498,14 +500,18 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
prstate.ndead > 0 ||
prstate.nunused > 0;
+ /* Record number of newly-set-LP_DEAD items for caller */
+ presult->nnewlpdead = prstate.ndead;
+
/*
- * Only incur overhead of checking if we will do an FPI if we might use
- * the information.
+ * Even if we don't prune anything, if we found a new value for the
+ * pd_prune_xid field or the page was marked full, we will update the hint
+ * bit.
*/
- if (do_prune && pagefrz)
- prune_fpi = XLogCheckBufferNeedsBackup(buffer);
+ do_hint = ((PageHeader) page)->pd_prune_xid != prstate.new_prune_xid ||
+ PageIsFull(page);
- /* Is the whole page freezable? And is there something to freeze */
+ /* Is the whole page freezable? And is there something to freeze? */
whole_page_freezable = presult->all_visible_except_removable &&
presult->all_frozen;
@@ -520,43 +526,51 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
* opportunistic freeze heuristic must be improved; however, for now, try
* to approximate it.
*/
- do_freeze = pagefrz &&
- (pagefrz->freeze_required ||
- (whole_page_freezable && presult->nfrozen > 0 && (prune_fpi || hint_bit_fpi)));
+ do_freeze = false;
+ if (pagefrz)
+ {
+ if (pagefrz->freeze_required)
+ do_freeze = true;
+ else if (whole_page_freezable && presult->nfrozen > 0)
+ {
+ /*
+ * Freezing would make the page all-frozen. In this case, we will
+ * freeze if we have already emitted an FPI or will do so anyway.
+ * Be sure only to incur the overhead of checking if we will do an
+ * FPI if we may use that information.
+ */
+ if (hint_bit_fpi ||
+ ((do_prune || do_hint) && XLogCheckBufferNeedsBackup(buffer)))
+ {
+ do_freeze = true;
+ }
+ }
+ }
+ /*
+ * Validate the tuples we are considering freezing. We do this even if
+ * pruning and hint bit setting have not emitted an FPI so far because we
+ * still may emit an FPI while setting the page hint bit later. But we
+ * want to avoid doing the pre-freeze checks in a critical section.
+ */
if (do_freeze)
- {
heap_pre_freeze_checks(buffer, prstate.frozen, presult->nfrozen);
+ if (!do_freeze && (!pagefrz || !presult->all_frozen || presult->nfrozen > 0))
+ {
/*
- * We can use frz_conflict_horizon as our cutoff for conflicts when
- * the whole page is eligible to become all-frozen in the VM once
- * we're done with it. Otherwise we generate a conservative cutoff by
- * stepping back from OldestXmin.
+ * If we will neither freeze tuples on the page nor set the page all
+ * frozen in the visibility map, the page is not all-frozen and there
+ * will be no newly frozen tuples.
*/
- if (!(presult->all_visible_except_removable && presult->all_frozen))
- {
- /* Avoids false conflicts when hot_standby_feedback in use */
- presult->frz_conflict_horizon = pagefrz->cutoffs->OldestXmin;
- TransactionIdRetreat(presult->frz_conflict_horizon);
- }
+ presult->all_frozen = false;
+ presult->nfrozen = 0; /* avoid miscounts in instrumentation */
}
- /* Any error while applying the changes is critical */
START_CRIT_SECTION();
- /* Have we found any prunable items? */
- if (do_prune)
+ if (do_hint)
{
- /*
- * Apply the planned item changes, then repair page fragmentation, and
- * update the page's hint bit about whether it has free line pointers.
- */
- heap_page_prune_execute(buffer,
- prstate.redirected, prstate.nredirected,
- prstate.nowdead, prstate.ndead,
- prstate.nowunused, prstate.nunused);
-
/*
* Update the page's pd_prune_xid field to either zero, or the lowest
* XID of any soon-prunable tuple.
@@ -564,163 +578,159 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
((PageHeader) page)->pd_prune_xid = prstate.new_prune_xid;
/*
- * Also clear the "page is full" flag, since there's no point in
- * repeating the prune/defrag process until something else happens to
- * the page.
+ * Clear the "page is full" flag if it is set since there's no point
+ * in repeating the prune/defrag process until something else happens
+ * to the page.
*/
PageClearFull(page);
- MarkBufferDirty(buffer);
+ /*
+ * We only needed to update pd_prune_xid and clear the page-is-full
+ * hint bit, this is a non-WAL-logged hint. If we will also freeze or
+ * prune the page, we will mark the buffer dirty below.
+ */
+ if (!do_freeze && !do_prune)
+ MarkBufferDirtyHint(buffer, true);
+ }
+ if (do_prune || do_freeze)
+ {
/*
- * Emit a WAL XLOG_HEAP2_PRUNE record showing what we did
+ * Apply the planned item changes, then repair page fragmentation, and
+ * update the page's hint bit about whether it has free line pointers.
*/
- if (RelationNeedsWAL(relation))
+ if (do_prune)
{
- xl_heap_prune xlrec;
- XLogRecPtr recptr;
-
- xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
- xlrec.snapshotConflictHorizon = prstate.snapshotConflictHorizon;
- xlrec.nredirected = prstate.nredirected;
- xlrec.ndead = prstate.ndead;
-
- XLogBeginInsert();
- XLogRegisterData((char *) &xlrec, SizeOfHeapPrune);
-
- XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
+ heap_page_prune_execute(buffer,
+ prstate.redirected, prstate.nredirected,
+ prstate.nowdead, prstate.ndead,
+ prstate.nowunused, prstate.nunused);
+ }
+ if (do_freeze)
+ {
/*
- * The OffsetNumber arrays are not actually in the buffer, but we
- * pretend that they are. When XLogInsert stores the whole
- * buffer, the offset arrays need not be stored too.
+ * We can use frz_conflict_horizon as our cutoff for conflicts
+ * when the whole page is eligible to become all-frozen in the VM
+ * once we're done with it. Otherwise we generate a conservative
+ * cutoff by stepping back from OldestXmin. This avoids false
+ * conflicts when hot_standby_feedback is in use.
*/
- if (prstate.nredirected > 0)
- XLogRegisterBufData(0, (char *) prstate.redirected,
- prstate.nredirected *
- sizeof(OffsetNumber) * 2);
-
- if (prstate.ndead > 0)
- XLogRegisterBufData(0, (char *) prstate.nowdead,
- prstate.ndead * sizeof(OffsetNumber));
-
- if (prstate.nunused > 0)
- XLogRegisterBufData(0, (char *) prstate.nowunused,
- prstate.nunused * sizeof(OffsetNumber));
+ if (!(presult->all_visible_except_removable && presult->all_frozen))
+ {
+ presult->frz_conflict_horizon = pagefrz->cutoffs->OldestXmin;
+ TransactionIdRetreat(presult->frz_conflict_horizon);
+ }
+ heap_freeze_prepared_tuples(buffer, prstate.frozen, presult->nfrozen);
+ }
- recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
+ MarkBufferDirty(buffer);
- PageSetLSN(BufferGetPage(buffer), recptr);
- }
- }
- else
- {
/*
- * If we didn't prune anything, but have found a new value for the
- * pd_prune_xid field, update it and mark the buffer dirty. This is
- * treated as a non-WAL-logged hint.
- *
- * Also clear the "page is full" flag if it is set, since there's no
- * point in repeating the prune/defrag process until something else
- * happens to the page.
+ * Emit a WAL XLOG_HEAP2_PRUNE record showing what we did
*/
- if (((PageHeader) page)->pd_prune_xid != prstate.new_prune_xid ||
- PageIsFull(page))
- {
- ((PageHeader) page)->pd_prune_xid = prstate.new_prune_xid;
- PageClearFull(page);
- MarkBufferDirtyHint(buffer, true);
- }
+ if (RelationNeedsWAL(relation))
+ log_heap_prune_and_freeze(relation, buffer, &prstate, presult);
}
END_CRIT_SECTION();
- /* Record number of newly-set-LP_DEAD items for caller */
- presult->nnewlpdead = prstate.ndead;
-
- if (do_freeze)
+ /*
+ * If we froze tuples on the page, the caller can advance relfrozenxid and
+ * relminmxid to the values in pagefrz->FreezePageRelfrozenXid and
+ * pagefrz->FreezePageRelminMxid. Otherwise, it is only safe to advance to
+ * the values in pagefrz->NoFreezePage[RelfrozenXid|RelminMxid]
+ */
+ if (pagefrz)
{
- START_CRIT_SECTION();
+ if (presult->nfrozen > 0)
+ {
+ presult->new_relfrozenxid = pagefrz->FreezePageRelfrozenXid;
+ presult->new_relminmxid = pagefrz->FreezePageRelminMxid;
+ }
+ else
+ {
+ presult->new_relfrozenxid = pagefrz->NoFreezePageRelfrozenXid;
+ presult->new_relminmxid = pagefrz->NoFreezePageRelminMxid;
+ }
+ }
+}
- Assert(presult->nfrozen > 0);
- heap_freeze_prepared_tuples(buffer, prstate.frozen, presult->nfrozen);
+static void
+log_heap_prune_and_freeze(Relation relation, Buffer buffer,
+ PruneState *prstate, PruneFreezeResult *presult)
+{
+ xl_heap_prune xlrec;
+ XLogRecPtr recptr;
- MarkBufferDirty(buffer);
+ xl_heap_freeze_plan plans[MaxHeapTuplesPerPage];
+ OffsetNumber offsets[MaxHeapTuplesPerPage];
+ bool do_freeze = presult->nfrozen > 0;
- /* Now WAL-log freezing if necessary */
- if (RelationNeedsWAL(relation))
- {
- xl_heap_freeze_plan plans[MaxHeapTuplesPerPage];
- OffsetNumber offsets[MaxHeapTuplesPerPage];
- int nplans;
- xl_heap_freeze_page xlrec;
- XLogRecPtr recptr;
+ xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
+ xlrec.nredirected = prstate->nredirected;
+ xlrec.ndead = prstate->ndead;
+ xlrec.nunused = prstate->nunused;
+ xlrec.nplans = 0;
- /*
- * Prepare deduplicated representation for use in WAL record
- * Destructively sorts tuples array in-place.
- */
- nplans = heap_log_freeze_plan(prstate.frozen, presult->nfrozen, plans, offsets);
+ /*
+ * The snapshotConflictHorizon for the whole record should be the most
+ * conservative of all the horizons calculated for any of the possible
+ * modifications. If this record will prune tuples, any transactions on
+ * the standby older than the youngest xmax of the most recently removed
+ * tuple this record will prune will conflict. If this record will freeze
+ * tuples, any transactions on the standby with xids older than the
+ * youngest tuple this record will freeze will conflict.
+ */
+ if (do_freeze)
+ xlrec.snapshotConflictHorizon = Max(prstate->snapshotConflictHorizon,
+ presult->frz_conflict_horizon);
+ else
+ xlrec.snapshotConflictHorizon = prstate->snapshotConflictHorizon;
- xlrec.snapshotConflictHorizon = presult->frz_conflict_horizon;
- xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
- xlrec.nplans = nplans;
+ /*
+ * Prepare deduplicated representation for use in WAL record Destructively
+ * sorts tuples array in-place.
+ */
+ if (do_freeze)
+ xlrec.nplans = heap_log_freeze_plan(prstate->frozen,
+ presult->nfrozen, plans, offsets);
- XLogBeginInsert();
- XLogRegisterData((char *) &xlrec, SizeOfHeapFreezePage);
+ XLogBeginInsert();
+ XLogRegisterData((char *) &xlrec, SizeOfHeapPrune);
- /*
- * The freeze plan array and offset array are not actually in the
- * buffer, but pretend that they are. When XLogInsert stores the
- * whole buffer, the arrays need not be stored too.
- */
- XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
- XLogRegisterBufData(0, (char *) plans,
- nplans * sizeof(xl_heap_freeze_plan));
- XLogRegisterBufData(0, (char *) offsets,
- presult->nfrozen * sizeof(OffsetNumber));
+ XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
- recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_FREEZE_PAGE);
+ /*
+ * The OffsetNumber arrays are not actually in the buffer, but we pretend
+ * that they are. When XLogInsert stores the whole buffer, the offset
+ * arrays need not be stored too.
+ */
+ if (xlrec.nplans > 0)
+ XLogRegisterBufData(0, (char *) plans,
+ xlrec.nplans * sizeof(xl_heap_freeze_plan));
- PageSetLSN(page, recptr);
- }
+ if (prstate->nredirected > 0)
+ XLogRegisterBufData(0, (char *) prstate->redirected,
+ prstate->nredirected *
+ sizeof(OffsetNumber) * 2);
- END_CRIT_SECTION();
- }
- else if (!pagefrz || !presult->all_frozen || presult->nfrozen > 0)
- {
- /*
- * If we will neither freeze tuples on the page nor set the page all
- * frozen in the visibility map, the page is not all frozen and there
- * will be no newly frozen tuples.
- */
- presult->all_frozen = false;
- presult->nfrozen = 0; /* avoid miscounts in instrumentation */
- }
+ if (prstate->ndead > 0)
+ XLogRegisterBufData(0, (char *) prstate->nowdead,
+ prstate->ndead * sizeof(OffsetNumber));
- /* Caller won't update new_relfrozenxid and new_relminmxid */
- if (!pagefrz)
- return;
+ if (prstate->nunused > 0)
+ XLogRegisterBufData(0, (char *) prstate->nowunused,
+ prstate->nunused * sizeof(OffsetNumber));
+ if (xlrec.nplans > 0)
+ XLogRegisterBufData(0, (char *) offsets,
+ presult->nfrozen * sizeof(OffsetNumber));
- /*
- * If we will freeze tuples on the page or, even if we don't freeze tuples
- * on the page, if we will set the page all-frozen in the visibility map,
- * we can advance relfrozenxid and relminmxid to the values in
- * pagefrz->FreezePageRelfrozenXid and pagefrz->FreezePageRelminMxid.
- */
- if (presult->all_frozen || presult->nfrozen > 0)
- {
- presult->new_relfrozenxid = pagefrz->FreezePageRelfrozenXid;
- presult->new_relminmxid = pagefrz->FreezePageRelminMxid;
- }
- else
- {
- presult->new_relfrozenxid = pagefrz->NoFreezePageRelfrozenXid;
- presult->new_relminmxid = pagefrz->NoFreezePageRelminMxid;
- }
-}
+ recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
+ PageSetLSN(BufferGetPage(buffer), recptr);
+}
/*
* Perform visibility checks for heap pruning.
diff --git a/src/backend/access/rmgrdesc/heapdesc.c b/src/backend/access/rmgrdesc/heapdesc.c
index 36a3d83c8c2..9f0a0341d40 100644
--- a/src/backend/access/rmgrdesc/heapdesc.c
+++ b/src/backend/access/rmgrdesc/heapdesc.c
@@ -179,43 +179,67 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
{
xl_heap_prune *xlrec = (xl_heap_prune *) rec;
- appendStringInfo(buf, "snapshotConflictHorizon: %u, nredirected: %u, ndead: %u, isCatalogRel: %c",
+ appendStringInfo(buf, "snapshotConflictHorizon: %u, isCatalogRel: %c",
xlrec->snapshotConflictHorizon,
- xlrec->nredirected,
- xlrec->ndead,
xlrec->isCatalogRel ? 'T' : 'F');
if (XLogRecHasBlockData(record, 0))
{
- OffsetNumber *end;
OffsetNumber *redirected;
OffsetNumber *nowdead;
OffsetNumber *nowunused;
int nredirected;
+ int ndead;
int nunused;
+ int nplans;
Size datalen;
+ xl_heap_freeze_plan *plans;
+ OffsetNumber *frz_offsets;
- redirected = (OffsetNumber *) XLogRecGetBlockData(record, 0,
- &datalen);
-
+ nplans = xlrec->nplans;
nredirected = xlrec->nredirected;
- end = (OffsetNumber *) ((char *) redirected + datalen);
- nowdead = redirected + (nredirected * 2);
- nowunused = nowdead + xlrec->ndead;
- nunused = (end - nowunused);
- Assert(nunused >= 0);
+ ndead = xlrec->ndead;
+ nunused = xlrec->nunused;
- appendStringInfo(buf, ", nunused: %d", nunused);
-
- appendStringInfoString(buf, ", redirected:");
- array_desc(buf, redirected, sizeof(OffsetNumber) * 2,
- nredirected, &redirect_elem_desc, NULL);
- appendStringInfoString(buf, ", dead:");
- array_desc(buf, nowdead, sizeof(OffsetNumber), xlrec->ndead,
- &offset_elem_desc, NULL);
- appendStringInfoString(buf, ", unused:");
- array_desc(buf, nowunused, sizeof(OffsetNumber), nunused,
- &offset_elem_desc, NULL);
+ plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, &datalen);
+ redirected = (OffsetNumber *) &plans[nplans];
+ nowdead = redirected + (nredirected * 2);
+ nowunused = nowdead + ndead;
+ frz_offsets = nowunused + nunused;
+
+ appendStringInfo(buf, ", nredirected: %u, ndead: %u, nunused: %u, nplans: %u,",
+ nredirected,
+ ndead,
+ nunused,
+ nplans);
+
+ if (nredirected > 0)
+ {
+ appendStringInfoString(buf, ", redirected:");
+ array_desc(buf, redirected, sizeof(OffsetNumber) * 2,
+ nredirected, &redirect_elem_desc, NULL);
+ }
+
+ if (ndead > 0)
+ {
+ appendStringInfoString(buf, ", dead:");
+ array_desc(buf, nowdead, sizeof(OffsetNumber), ndead,
+ &offset_elem_desc, NULL);
+ }
+
+ if (nunused > 0)
+ {
+ appendStringInfoString(buf, ", unused:");
+ array_desc(buf, nowunused, sizeof(OffsetNumber), nunused,
+ &offset_elem_desc, NULL);
+ }
+
+ if (nplans > 0)
+ {
+ appendStringInfoString(buf, ", plans:");
+ array_desc(buf, plans, sizeof(xl_heap_freeze_plan), nplans,
+ &plan_elem_desc, &frz_offsets);
+ }
}
}
else if (info == XLOG_HEAP2_VACUUM)
@@ -235,28 +259,6 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
&offset_elem_desc, NULL);
}
}
- else if (info == XLOG_HEAP2_FREEZE_PAGE)
- {
- xl_heap_freeze_page *xlrec = (xl_heap_freeze_page *) rec;
-
- appendStringInfo(buf, "snapshotConflictHorizon: %u, nplans: %u, isCatalogRel: %c",
- xlrec->snapshotConflictHorizon, xlrec->nplans,
- xlrec->isCatalogRel ? 'T' : 'F');
-
- if (XLogRecHasBlockData(record, 0))
- {
- xl_heap_freeze_plan *plans;
- OffsetNumber *offsets;
-
- plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, NULL);
- offsets = (OffsetNumber *) ((char *) plans +
- (xlrec->nplans *
- sizeof(xl_heap_freeze_plan)));
- appendStringInfoString(buf, ", plans:");
- array_desc(buf, plans, sizeof(xl_heap_freeze_plan), xlrec->nplans,
- &plan_elem_desc, &offsets);
- }
- }
else if (info == XLOG_HEAP2_VISIBLE)
{
xl_heap_visible *xlrec = (xl_heap_visible *) rec;
@@ -361,9 +363,6 @@ heap2_identify(uint8 info)
case XLOG_HEAP2_VACUUM:
id = "VACUUM";
break;
- case XLOG_HEAP2_FREEZE_PAGE:
- id = "FREEZE_PAGE";
- break;
case XLOG_HEAP2_VISIBLE:
id = "VISIBLE";
break;
diff --git a/src/backend/replication/logical/decode.c b/src/backend/replication/logical/decode.c
index e5ab7b78b78..f77051572fd 100644
--- a/src/backend/replication/logical/decode.c
+++ b/src/backend/replication/logical/decode.c
@@ -445,7 +445,6 @@ heap2_decode(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
* Everything else here is just low level physical stuff we're not
* interested in.
*/
- case XLOG_HEAP2_FREEZE_PAGE:
case XLOG_HEAP2_PRUNE:
case XLOG_HEAP2_VACUUM:
case XLOG_HEAP2_VISIBLE:
diff --git a/src/include/access/heapam_xlog.h b/src/include/access/heapam_xlog.h
index 6488dad5e64..fe4a8ff0620 100644
--- a/src/include/access/heapam_xlog.h
+++ b/src/include/access/heapam_xlog.h
@@ -53,11 +53,10 @@
#define XLOG_HEAP2_REWRITE 0x00
#define XLOG_HEAP2_PRUNE 0x10
#define XLOG_HEAP2_VACUUM 0x20
-#define XLOG_HEAP2_FREEZE_PAGE 0x30
-#define XLOG_HEAP2_VISIBLE 0x40
-#define XLOG_HEAP2_MULTI_INSERT 0x50
-#define XLOG_HEAP2_LOCK_UPDATED 0x60
-#define XLOG_HEAP2_NEW_CID 0x70
+#define XLOG_HEAP2_VISIBLE 0x30
+#define XLOG_HEAP2_MULTI_INSERT 0x40
+#define XLOG_HEAP2_LOCK_UPDATED 0x50
+#define XLOG_HEAP2_NEW_CID 0x60
/*
* xl_heap_insert/xl_heap_multi_insert flag values, 8 bits are available.
@@ -226,28 +225,65 @@ typedef struct xl_heap_update
#define SizeOfHeapUpdate (offsetof(xl_heap_update, new_offnum) + sizeof(OffsetNumber))
+/*
+ * This struct represents a 'freeze plan', which describes how to freeze a
+ * group of one or more heap tuples (appears in xl_heap_prune record)
+ */
+/* 0x01 was XLH_FREEZE_XMIN */
+#define XLH_FREEZE_XVAC 0x02
+#define XLH_INVALID_XVAC 0x04
+
+typedef struct xl_heap_freeze_plan
+{
+ TransactionId xmax;
+ uint16 t_infomask2;
+ uint16 t_infomask;
+ uint8 frzflags;
+
+ /* Length of individual page offset numbers array for this plan */
+ uint16 ntuples;
+} xl_heap_freeze_plan;
+
+/*
+ * As of Postgres 17, XLOG_HEAP2_PRUNE records replace
+ * XLOG_HEAP2_FREEZE_PAGE records.
+ */
+
/*
* This is what we need to know about page pruning (both during VACUUM and
* during opportunistic pruning)
*
* The array of OffsetNumbers following the fixed part of the record contains:
+ * * for each freeze plan: the freeze plan
* * for each redirected item: the item offset, then the offset redirected to
* * for each now-dead item: the item offset
* * for each now-unused item: the item offset
- * The total number of OffsetNumbers is therefore 2*nredirected+ndead+nunused.
- * Note that nunused is not explicitly stored, but may be found by reference
- * to the total record length.
+ * * for each tuple frozen by the freeze plans: the offset of the item corresponding to that tuple
+ * The total number of OffsetNumbers is therefore
+ * (2*nredirected) + ndead + nunused + (sum[plan.ntuples for plan in plans])
*
- * Acquires a full cleanup lock.
+ * Acquires a full cleanup lock if heap_page_prune_execute() must be called
*/
typedef struct xl_heap_prune
{
TransactionId snapshotConflictHorizon;
+ uint16 nplans;
uint16 nredirected;
uint16 ndead;
+ uint16 nunused;
bool isCatalogRel; /* to handle recovery conflict during logical
* decoding on standby */
- /* OFFSET NUMBERS are in the block reference 0 */
+ /*--------------------------------------------------------------------
+ * OFFSET NUMBERS and freeze plans are in the block reference 0 in the
+ * following order:
+ *
+ * * xl_heap_freeze_plan plans[nplans];
+ * * OffsetNumber redirected[2 * nredirected];
+ * * OffsetNumber nowdead[ndead];
+ * * OffsetNumber nowunused[nunused];
+ * * OffsetNumber frz_offsets[...];
+ *--------------------------------------------------------------------
+ */
} xl_heap_prune;
#define SizeOfHeapPrune (offsetof(xl_heap_prune, isCatalogRel) + sizeof(bool))
@@ -315,47 +351,6 @@ typedef struct xl_heap_inplace
#define SizeOfHeapInplace (offsetof(xl_heap_inplace, offnum) + sizeof(OffsetNumber))
-/*
- * This struct represents a 'freeze plan', which describes how to freeze a
- * group of one or more heap tuples (appears in xl_heap_freeze_page record)
- */
-/* 0x01 was XLH_FREEZE_XMIN */
-#define XLH_FREEZE_XVAC 0x02
-#define XLH_INVALID_XVAC 0x04
-
-typedef struct xl_heap_freeze_plan
-{
- TransactionId xmax;
- uint16 t_infomask2;
- uint16 t_infomask;
- uint8 frzflags;
-
- /* Length of individual page offset numbers array for this plan */
- uint16 ntuples;
-} xl_heap_freeze_plan;
-
-/*
- * This is what we need to know about a block being frozen during vacuum
- *
- * Backup block 0's data contains an array of xl_heap_freeze_plan structs
- * (with nplans elements), followed by one or more page offset number arrays.
- * Each such page offset number array corresponds to a single freeze plan
- * (REDO routine freezes corresponding heap tuples using freeze plan).
- */
-typedef struct xl_heap_freeze_page
-{
- TransactionId snapshotConflictHorizon;
- uint16 nplans;
- bool isCatalogRel; /* to handle recovery conflict during logical
- * decoding on standby */
-
- /*
- * In payload of blk 0 : FREEZE PLANS and OFFSET NUMBER ARRAY
- */
-} xl_heap_freeze_page;
-
-#define SizeOfHeapFreezePage (offsetof(xl_heap_freeze_page, isCatalogRel) + sizeof(bool))
-
/*
* This is what we need to know about setting a visibility map bit
*
--
2.40.1
--tez7m2a73jtztiij
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0014-Vacuum-second-pass-emits-XLOG_HEAP2_PRUNE-record.patch"
^ permalink raw reply [nested|flat] 15+ messages in thread
* [PATCH v2 12/17] Merge prune and freeze records
@ 2024-01-07 22:55 Melanie Plageman <[email protected]>
0 siblings, 0 replies; 15+ messages in thread
From: Melanie Plageman @ 2024-01-07 22:55 UTC (permalink / raw)
When there are both tuples to prune and freeze on a page, emit a single,
combined prune record containing the offsets for pruning and the freeze
plans and offsets for freezing. This will reduce the number of WAL
records emitted.
---
src/backend/access/heap/heapam.c | 42 ++++++++++++--
src/backend/access/heap/pruneheap.c | 85 +++++++++++++----------------
src/include/access/heapam_xlog.h | 20 +++++--
3 files changed, 90 insertions(+), 57 deletions(-)
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index a3691584c55..a8f35eba3c9 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -8803,24 +8803,28 @@ heap_xlog_prune(XLogReaderState *record)
if (action == BLK_NEEDS_REDO)
{
Page page = (Page) BufferGetPage(buffer);
- OffsetNumber *end;
OffsetNumber *redirected;
OffsetNumber *nowdead;
OffsetNumber *nowunused;
int nredirected;
int ndead;
int nunused;
+ int nplans;
Size datalen;
+ xl_heap_freeze_plan *plans;
+ OffsetNumber *frz_offsets;
+ int curoff = 0;
- redirected = (OffsetNumber *) XLogRecGetBlockData(record, 0, &datalen);
-
+ nplans = xlrec->nplans;
nredirected = xlrec->nredirected;
ndead = xlrec->ndead;
- end = (OffsetNumber *) ((char *) redirected + datalen);
+ nunused = xlrec->nunused;
+
+ plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, &datalen);
+ redirected = (OffsetNumber *) &plans[nplans];
nowdead = redirected + (nredirected * 2);
nowunused = nowdead + ndead;
- nunused = (end - nowunused);
- Assert(nunused >= 0);
+ frz_offsets = nowunused + nunused;
/* Update all line pointers per the record, and repair fragmentation */
heap_page_prune_execute(buffer,
@@ -8828,6 +8832,32 @@ heap_xlog_prune(XLogReaderState *record)
nowdead, ndead,
nowunused, nunused);
+ for (int p = 0; p < nplans; p++)
+ {
+ HeapTupleFreeze frz;
+
+ /*
+ * Convert freeze plan representation from WAL record into
+ * per-tuple format used by heap_execute_freeze_tuple
+ */
+ frz.xmax = plans[p].xmax;
+ frz.t_infomask2 = plans[p].t_infomask2;
+ frz.t_infomask = plans[p].t_infomask;
+ frz.frzflags = plans[p].frzflags;
+ frz.offset = InvalidOffsetNumber; /* unused, but be tidy */
+
+ for (int i = 0; i < plans[p].ntuples; i++)
+ {
+ OffsetNumber offset = frz_offsets[curoff++];
+ ItemId lp;
+ HeapTupleHeader tuple;
+
+ lp = PageGetItemId(page, offset);
+ tuple = (HeapTupleHeader) PageGetItem(page, lp);
+ heap_execute_freeze_tuple(tuple, &frz);
+ }
+ }
+
/*
* Note: we don't worry about updating the page's prunability hints.
* At worst this will cause an extra prune cycle to occur soon.
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index ca64c45d8a3..70d35a21e98 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -605,6 +605,9 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
*/
PageClearFull(page);
+ if (do_freeze)
+ heap_freeze_prepared_tuples(buffer, frozen, presult->nfrozen);
+
MarkBufferDirty(buffer);
/*
@@ -615,10 +618,37 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
xl_heap_prune xlrec;
XLogRecPtr recptr;
+ xl_heap_freeze_plan plans[MaxHeapTuplesPerPage];
+ OffsetNumber offsets[MaxHeapTuplesPerPage];
+
xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
- xlrec.snapshotConflictHorizon = prstate.snapshotConflictHorizon;
xlrec.nredirected = prstate.nredirected;
xlrec.ndead = prstate.ndead;
+ xlrec.nunused = prstate.nunused;
+ xlrec.nplans = 0;
+
+ /*
+ * The snapshotConflictHorizon for the whole record should be the most
+ * conservative of all the horizons calculated for any of the possible
+ * modifications. If this record will prune tuples, any transactions
+ * on the standby older than the youngest xmax of the most recently
+ * removed tuple this record will prune will conflict. If this record
+ * will freeze tuples, any transactions on the standby with xids older
+ * than the youngest tuple this record will freeze will conflict.
+ */
+ if (do_freeze)
+ xlrec.snapshotConflictHorizon = Max(prstate.snapshotConflictHorizon,
+ frz_conflict_horizon);
+ else
+ xlrec.snapshotConflictHorizon = prstate.snapshotConflictHorizon;
+
+ /*
+ * Prepare deduplicated representation for use in WAL record
+ * Destructively sorts tuples array in-place.
+ */
+ if (do_freeze)
+ xlrec.nplans = heap_log_freeze_plan(frozen,
+ presult->nfrozen, plans, offsets);
XLogBeginInsert();
XLogRegisterData((char *) &xlrec, SizeOfHeapPrune);
@@ -630,6 +660,10 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
* pretend that they are. When XLogInsert stores the whole buffer,
* the offset arrays need not be stored too.
*/
+ if (xlrec.nplans > 0)
+ XLogRegisterBufData(0, (char *) plans,
+ xlrec.nplans * sizeof(xl_heap_freeze_plan));
+
if (prstate.nredirected > 0)
XLogRegisterBufData(0, (char *) prstate.redirected,
prstate.nredirected *
@@ -643,56 +677,13 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
XLogRegisterBufData(0, (char *) prstate.nowunused,
prstate.nunused * sizeof(OffsetNumber));
- recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
-
- PageSetLSN(BufferGetPage(buffer), recptr);
- }
-
- if (do_freeze)
- {
- Assert(presult->nfrozen > 0);
-
- heap_freeze_prepared_tuples(buffer, frozen, presult->nfrozen);
-
- MarkBufferDirty(buffer);
-
- /* Now WAL-log freezing if necessary */
- if (RelationNeedsWAL(relation))
- {
- xl_heap_freeze_plan plans[MaxHeapTuplesPerPage];
- OffsetNumber offsets[MaxHeapTuplesPerPage];
- int nplans;
- xl_heap_freeze_page xlrec;
- XLogRecPtr recptr;
-
- /*
- * Prepare deduplicated representation for use in WAL record
- * Destructively sorts tuples array in-place.
- */
- nplans = heap_log_freeze_plan(frozen, presult->nfrozen, plans, offsets);
-
- xlrec.snapshotConflictHorizon = frz_conflict_horizon;
- xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
- xlrec.nplans = nplans;
-
- XLogBeginInsert();
- XLogRegisterData((char *) &xlrec, SizeOfHeapFreezePage);
-
- /*
- * The freeze plan array and offset array are not actually in the
- * buffer, but pretend that they are. When XLogInsert stores the
- * whole buffer, the arrays need not be stored too.
- */
- XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
- XLogRegisterBufData(0, (char *) plans,
- nplans * sizeof(xl_heap_freeze_plan));
+ if (xlrec.nplans > 0)
XLogRegisterBufData(0, (char *) offsets,
presult->nfrozen * sizeof(OffsetNumber));
- recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_FREEZE_PAGE);
+ recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
- PageSetLSN(page, recptr);
- }
+ PageSetLSN(BufferGetPage(buffer), recptr);
}
END_CRIT_SECTION();
diff --git a/src/include/access/heapam_xlog.h b/src/include/access/heapam_xlog.h
index 6488dad5e64..22f236bb52a 100644
--- a/src/include/access/heapam_xlog.h
+++ b/src/include/access/heapam_xlog.h
@@ -231,23 +231,35 @@ typedef struct xl_heap_update
* during opportunistic pruning)
*
* The array of OffsetNumbers following the fixed part of the record contains:
+ * * for each freeze plan: the freeze plan
* * for each redirected item: the item offset, then the offset redirected to
* * for each now-dead item: the item offset
* * for each now-unused item: the item offset
- * The total number of OffsetNumbers is therefore 2*nredirected+ndead+nunused.
- * Note that nunused is not explicitly stored, but may be found by reference
- * to the total record length.
+ * * for each tuple frozen by the freeze plans: the offset of the item corresponding to that tuple
+ * The total number of OffsetNumbers is therefore
+ * (2*nredirected) + ndead + nunused + (sum[plan.ntuples for plan in plans])
*
* Acquires a full cleanup lock.
*/
typedef struct xl_heap_prune
{
TransactionId snapshotConflictHorizon;
+ uint16 nplans;
uint16 nredirected;
uint16 ndead;
+ uint16 nunused;
bool isCatalogRel; /* to handle recovery conflict during logical
* decoding on standby */
- /* OFFSET NUMBERS are in the block reference 0 */
+ /*
+ * OFFSET NUMBERS and freeze plans are in the block reference 0 in the
+ * following order:
+ *
+ * * xl_heap_freeze_plan plans[nplans];
+ * * OffsetNumber redirected[2 * nredirected];
+ * * OffsetNumber nowdead[ndead];
+ * * OffsetNumber nowunused[nunused];
+ * * OffsetNumber frz_offsets[...];
+ */
} xl_heap_prune;
#define SizeOfHeapPrune (offsetof(xl_heap_prune, isCatalogRel) + sizeof(bool))
--
2.40.1
--rdqtp5puvxqotfdw
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v2-0013-Set-hastup-in-heap_page_prune.patch"
^ permalink raw reply [nested|flat] 15+ messages in thread
* [PATCH v2 12/17] Merge prune and freeze records
@ 2024-01-07 22:55 Melanie Plageman <[email protected]>
0 siblings, 0 replies; 15+ messages in thread
From: Melanie Plageman @ 2024-01-07 22:55 UTC (permalink / raw)
When there are both tuples to prune and freeze on a page, emit a single,
combined prune record containing the offsets for pruning and the freeze
plans and offsets for freezing. This will reduce the number of WAL
records emitted.
---
src/backend/access/heap/heapam.c | 42 ++++++++++++--
src/backend/access/heap/pruneheap.c | 85 +++++++++++++----------------
src/include/access/heapam_xlog.h | 20 +++++--
3 files changed, 90 insertions(+), 57 deletions(-)
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index a3691584c55..a8f35eba3c9 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -8803,24 +8803,28 @@ heap_xlog_prune(XLogReaderState *record)
if (action == BLK_NEEDS_REDO)
{
Page page = (Page) BufferGetPage(buffer);
- OffsetNumber *end;
OffsetNumber *redirected;
OffsetNumber *nowdead;
OffsetNumber *nowunused;
int nredirected;
int ndead;
int nunused;
+ int nplans;
Size datalen;
+ xl_heap_freeze_plan *plans;
+ OffsetNumber *frz_offsets;
+ int curoff = 0;
- redirected = (OffsetNumber *) XLogRecGetBlockData(record, 0, &datalen);
-
+ nplans = xlrec->nplans;
nredirected = xlrec->nredirected;
ndead = xlrec->ndead;
- end = (OffsetNumber *) ((char *) redirected + datalen);
+ nunused = xlrec->nunused;
+
+ plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, &datalen);
+ redirected = (OffsetNumber *) &plans[nplans];
nowdead = redirected + (nredirected * 2);
nowunused = nowdead + ndead;
- nunused = (end - nowunused);
- Assert(nunused >= 0);
+ frz_offsets = nowunused + nunused;
/* Update all line pointers per the record, and repair fragmentation */
heap_page_prune_execute(buffer,
@@ -8828,6 +8832,32 @@ heap_xlog_prune(XLogReaderState *record)
nowdead, ndead,
nowunused, nunused);
+ for (int p = 0; p < nplans; p++)
+ {
+ HeapTupleFreeze frz;
+
+ /*
+ * Convert freeze plan representation from WAL record into
+ * per-tuple format used by heap_execute_freeze_tuple
+ */
+ frz.xmax = plans[p].xmax;
+ frz.t_infomask2 = plans[p].t_infomask2;
+ frz.t_infomask = plans[p].t_infomask;
+ frz.frzflags = plans[p].frzflags;
+ frz.offset = InvalidOffsetNumber; /* unused, but be tidy */
+
+ for (int i = 0; i < plans[p].ntuples; i++)
+ {
+ OffsetNumber offset = frz_offsets[curoff++];
+ ItemId lp;
+ HeapTupleHeader tuple;
+
+ lp = PageGetItemId(page, offset);
+ tuple = (HeapTupleHeader) PageGetItem(page, lp);
+ heap_execute_freeze_tuple(tuple, &frz);
+ }
+ }
+
/*
* Note: we don't worry about updating the page's prunability hints.
* At worst this will cause an extra prune cycle to occur soon.
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index ca64c45d8a3..70d35a21e98 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -605,6 +605,9 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
*/
PageClearFull(page);
+ if (do_freeze)
+ heap_freeze_prepared_tuples(buffer, frozen, presult->nfrozen);
+
MarkBufferDirty(buffer);
/*
@@ -615,10 +618,37 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
xl_heap_prune xlrec;
XLogRecPtr recptr;
+ xl_heap_freeze_plan plans[MaxHeapTuplesPerPage];
+ OffsetNumber offsets[MaxHeapTuplesPerPage];
+
xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
- xlrec.snapshotConflictHorizon = prstate.snapshotConflictHorizon;
xlrec.nredirected = prstate.nredirected;
xlrec.ndead = prstate.ndead;
+ xlrec.nunused = prstate.nunused;
+ xlrec.nplans = 0;
+
+ /*
+ * The snapshotConflictHorizon for the whole record should be the most
+ * conservative of all the horizons calculated for any of the possible
+ * modifications. If this record will prune tuples, any transactions
+ * on the standby older than the youngest xmax of the most recently
+ * removed tuple this record will prune will conflict. If this record
+ * will freeze tuples, any transactions on the standby with xids older
+ * than the youngest tuple this record will freeze will conflict.
+ */
+ if (do_freeze)
+ xlrec.snapshotConflictHorizon = Max(prstate.snapshotConflictHorizon,
+ frz_conflict_horizon);
+ else
+ xlrec.snapshotConflictHorizon = prstate.snapshotConflictHorizon;
+
+ /*
+ * Prepare deduplicated representation for use in WAL record
+ * Destructively sorts tuples array in-place.
+ */
+ if (do_freeze)
+ xlrec.nplans = heap_log_freeze_plan(frozen,
+ presult->nfrozen, plans, offsets);
XLogBeginInsert();
XLogRegisterData((char *) &xlrec, SizeOfHeapPrune);
@@ -630,6 +660,10 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
* pretend that they are. When XLogInsert stores the whole buffer,
* the offset arrays need not be stored too.
*/
+ if (xlrec.nplans > 0)
+ XLogRegisterBufData(0, (char *) plans,
+ xlrec.nplans * sizeof(xl_heap_freeze_plan));
+
if (prstate.nredirected > 0)
XLogRegisterBufData(0, (char *) prstate.redirected,
prstate.nredirected *
@@ -643,56 +677,13 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
XLogRegisterBufData(0, (char *) prstate.nowunused,
prstate.nunused * sizeof(OffsetNumber));
- recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
-
- PageSetLSN(BufferGetPage(buffer), recptr);
- }
-
- if (do_freeze)
- {
- Assert(presult->nfrozen > 0);
-
- heap_freeze_prepared_tuples(buffer, frozen, presult->nfrozen);
-
- MarkBufferDirty(buffer);
-
- /* Now WAL-log freezing if necessary */
- if (RelationNeedsWAL(relation))
- {
- xl_heap_freeze_plan plans[MaxHeapTuplesPerPage];
- OffsetNumber offsets[MaxHeapTuplesPerPage];
- int nplans;
- xl_heap_freeze_page xlrec;
- XLogRecPtr recptr;
-
- /*
- * Prepare deduplicated representation for use in WAL record
- * Destructively sorts tuples array in-place.
- */
- nplans = heap_log_freeze_plan(frozen, presult->nfrozen, plans, offsets);
-
- xlrec.snapshotConflictHorizon = frz_conflict_horizon;
- xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
- xlrec.nplans = nplans;
-
- XLogBeginInsert();
- XLogRegisterData((char *) &xlrec, SizeOfHeapFreezePage);
-
- /*
- * The freeze plan array and offset array are not actually in the
- * buffer, but pretend that they are. When XLogInsert stores the
- * whole buffer, the arrays need not be stored too.
- */
- XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
- XLogRegisterBufData(0, (char *) plans,
- nplans * sizeof(xl_heap_freeze_plan));
+ if (xlrec.nplans > 0)
XLogRegisterBufData(0, (char *) offsets,
presult->nfrozen * sizeof(OffsetNumber));
- recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_FREEZE_PAGE);
+ recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
- PageSetLSN(page, recptr);
- }
+ PageSetLSN(BufferGetPage(buffer), recptr);
}
END_CRIT_SECTION();
diff --git a/src/include/access/heapam_xlog.h b/src/include/access/heapam_xlog.h
index 6488dad5e64..22f236bb52a 100644
--- a/src/include/access/heapam_xlog.h
+++ b/src/include/access/heapam_xlog.h
@@ -231,23 +231,35 @@ typedef struct xl_heap_update
* during opportunistic pruning)
*
* The array of OffsetNumbers following the fixed part of the record contains:
+ * * for each freeze plan: the freeze plan
* * for each redirected item: the item offset, then the offset redirected to
* * for each now-dead item: the item offset
* * for each now-unused item: the item offset
- * The total number of OffsetNumbers is therefore 2*nredirected+ndead+nunused.
- * Note that nunused is not explicitly stored, but may be found by reference
- * to the total record length.
+ * * for each tuple frozen by the freeze plans: the offset of the item corresponding to that tuple
+ * The total number of OffsetNumbers is therefore
+ * (2*nredirected) + ndead + nunused + (sum[plan.ntuples for plan in plans])
*
* Acquires a full cleanup lock.
*/
typedef struct xl_heap_prune
{
TransactionId snapshotConflictHorizon;
+ uint16 nplans;
uint16 nredirected;
uint16 ndead;
+ uint16 nunused;
bool isCatalogRel; /* to handle recovery conflict during logical
* decoding on standby */
- /* OFFSET NUMBERS are in the block reference 0 */
+ /*
+ * OFFSET NUMBERS and freeze plans are in the block reference 0 in the
+ * following order:
+ *
+ * * xl_heap_freeze_plan plans[nplans];
+ * * OffsetNumber redirected[2 * nredirected];
+ * * OffsetNumber nowdead[ndead];
+ * * OffsetNumber nowunused[nunused];
+ * * OffsetNumber frz_offsets[...];
+ */
} xl_heap_prune;
#define SizeOfHeapPrune (offsetof(xl_heap_prune, isCatalogRel) + sizeof(bool))
--
2.40.1
--rdqtp5puvxqotfdw
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v2-0013-Set-hastup-in-heap_page_prune.patch"
^ permalink raw reply [nested|flat] 15+ messages in thread
* [PATCH v3 12/17] Merge prune and freeze records
@ 2024-01-07 22:55 Melanie Plageman <[email protected]>
0 siblings, 0 replies; 15+ messages in thread
From: Melanie Plageman @ 2024-01-07 22:55 UTC (permalink / raw)
When there are both tuples to prune and freeze on a page, emit a single,
combined prune record containing the offsets for pruning and the freeze
plans and offsets for freezing. This will reduce the number of WAL
records emitted.
---
src/backend/access/heap/heapam.c | 42 ++++++++++++--
src/backend/access/heap/pruneheap.c | 85 +++++++++++++----------------
src/include/access/heapam_xlog.h | 20 +++++--
3 files changed, 90 insertions(+), 57 deletions(-)
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index a3691584c55..a8f35eba3c9 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -8803,24 +8803,28 @@ heap_xlog_prune(XLogReaderState *record)
if (action == BLK_NEEDS_REDO)
{
Page page = (Page) BufferGetPage(buffer);
- OffsetNumber *end;
OffsetNumber *redirected;
OffsetNumber *nowdead;
OffsetNumber *nowunused;
int nredirected;
int ndead;
int nunused;
+ int nplans;
Size datalen;
+ xl_heap_freeze_plan *plans;
+ OffsetNumber *frz_offsets;
+ int curoff = 0;
- redirected = (OffsetNumber *) XLogRecGetBlockData(record, 0, &datalen);
-
+ nplans = xlrec->nplans;
nredirected = xlrec->nredirected;
ndead = xlrec->ndead;
- end = (OffsetNumber *) ((char *) redirected + datalen);
+ nunused = xlrec->nunused;
+
+ plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, &datalen);
+ redirected = (OffsetNumber *) &plans[nplans];
nowdead = redirected + (nredirected * 2);
nowunused = nowdead + ndead;
- nunused = (end - nowunused);
- Assert(nunused >= 0);
+ frz_offsets = nowunused + nunused;
/* Update all line pointers per the record, and repair fragmentation */
heap_page_prune_execute(buffer,
@@ -8828,6 +8832,32 @@ heap_xlog_prune(XLogReaderState *record)
nowdead, ndead,
nowunused, nunused);
+ for (int p = 0; p < nplans; p++)
+ {
+ HeapTupleFreeze frz;
+
+ /*
+ * Convert freeze plan representation from WAL record into
+ * per-tuple format used by heap_execute_freeze_tuple
+ */
+ frz.xmax = plans[p].xmax;
+ frz.t_infomask2 = plans[p].t_infomask2;
+ frz.t_infomask = plans[p].t_infomask;
+ frz.frzflags = plans[p].frzflags;
+ frz.offset = InvalidOffsetNumber; /* unused, but be tidy */
+
+ for (int i = 0; i < plans[p].ntuples; i++)
+ {
+ OffsetNumber offset = frz_offsets[curoff++];
+ ItemId lp;
+ HeapTupleHeader tuple;
+
+ lp = PageGetItemId(page, offset);
+ tuple = (HeapTupleHeader) PageGetItem(page, lp);
+ heap_execute_freeze_tuple(tuple, &frz);
+ }
+ }
+
/*
* Note: we don't worry about updating the page's prunability hints.
* At worst this will cause an extra prune cycle to occur soon.
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index d77270ad0d6..994cf75c54e 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -619,6 +619,9 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
*/
PageClearFull(page);
+ if (do_freeze)
+ heap_freeze_prepared_tuples(buffer, frozen, presult->nfrozen);
+
MarkBufferDirty(buffer);
/*
@@ -629,10 +632,37 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
xl_heap_prune xlrec;
XLogRecPtr recptr;
+ xl_heap_freeze_plan plans[MaxHeapTuplesPerPage];
+ OffsetNumber offsets[MaxHeapTuplesPerPage];
+
xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
- xlrec.snapshotConflictHorizon = prstate.snapshotConflictHorizon;
xlrec.nredirected = prstate.nredirected;
xlrec.ndead = prstate.ndead;
+ xlrec.nunused = prstate.nunused;
+ xlrec.nplans = 0;
+
+ /*
+ * The snapshotConflictHorizon for the whole record should be the most
+ * conservative of all the horizons calculated for any of the possible
+ * modifications. If this record will prune tuples, any transactions
+ * on the standby older than the youngest xmax of the most recently
+ * removed tuple this record will prune will conflict. If this record
+ * will freeze tuples, any transactions on the standby with xids older
+ * than the youngest tuple this record will freeze will conflict.
+ */
+ if (do_freeze)
+ xlrec.snapshotConflictHorizon = Max(prstate.snapshotConflictHorizon,
+ frz_conflict_horizon);
+ else
+ xlrec.snapshotConflictHorizon = prstate.snapshotConflictHorizon;
+
+ /*
+ * Prepare deduplicated representation for use in WAL record
+ * Destructively sorts tuples array in-place.
+ */
+ if (do_freeze)
+ xlrec.nplans = heap_log_freeze_plan(frozen,
+ presult->nfrozen, plans, offsets);
XLogBeginInsert();
XLogRegisterData((char *) &xlrec, SizeOfHeapPrune);
@@ -644,6 +674,10 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
* pretend that they are. When XLogInsert stores the whole buffer,
* the offset arrays need not be stored too.
*/
+ if (xlrec.nplans > 0)
+ XLogRegisterBufData(0, (char *) plans,
+ xlrec.nplans * sizeof(xl_heap_freeze_plan));
+
if (prstate.nredirected > 0)
XLogRegisterBufData(0, (char *) prstate.redirected,
prstate.nredirected *
@@ -657,56 +691,13 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
XLogRegisterBufData(0, (char *) prstate.nowunused,
prstate.nunused * sizeof(OffsetNumber));
- recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
-
- PageSetLSN(BufferGetPage(buffer), recptr);
- }
-
- if (do_freeze)
- {
- Assert(presult->nfrozen > 0);
-
- heap_freeze_prepared_tuples(buffer, frozen, presult->nfrozen);
-
- MarkBufferDirty(buffer);
-
- /* Now WAL-log freezing if necessary */
- if (RelationNeedsWAL(relation))
- {
- xl_heap_freeze_plan plans[MaxHeapTuplesPerPage];
- OffsetNumber offsets[MaxHeapTuplesPerPage];
- int nplans;
- xl_heap_freeze_page xlrec;
- XLogRecPtr recptr;
-
- /*
- * Prepare deduplicated representation for use in WAL record
- * Destructively sorts tuples array in-place.
- */
- nplans = heap_log_freeze_plan(frozen, presult->nfrozen, plans, offsets);
-
- xlrec.snapshotConflictHorizon = frz_conflict_horizon;
- xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
- xlrec.nplans = nplans;
-
- XLogBeginInsert();
- XLogRegisterData((char *) &xlrec, SizeOfHeapFreezePage);
-
- /*
- * The freeze plan array and offset array are not actually in the
- * buffer, but pretend that they are. When XLogInsert stores the
- * whole buffer, the arrays need not be stored too.
- */
- XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
- XLogRegisterBufData(0, (char *) plans,
- nplans * sizeof(xl_heap_freeze_plan));
+ if (xlrec.nplans > 0)
XLogRegisterBufData(0, (char *) offsets,
presult->nfrozen * sizeof(OffsetNumber));
- recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_FREEZE_PAGE);
+ recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
- PageSetLSN(page, recptr);
- }
+ PageSetLSN(BufferGetPage(buffer), recptr);
}
END_CRIT_SECTION();
diff --git a/src/include/access/heapam_xlog.h b/src/include/access/heapam_xlog.h
index 6488dad5e64..22f236bb52a 100644
--- a/src/include/access/heapam_xlog.h
+++ b/src/include/access/heapam_xlog.h
@@ -231,23 +231,35 @@ typedef struct xl_heap_update
* during opportunistic pruning)
*
* The array of OffsetNumbers following the fixed part of the record contains:
+ * * for each freeze plan: the freeze plan
* * for each redirected item: the item offset, then the offset redirected to
* * for each now-dead item: the item offset
* * for each now-unused item: the item offset
- * The total number of OffsetNumbers is therefore 2*nredirected+ndead+nunused.
- * Note that nunused is not explicitly stored, but may be found by reference
- * to the total record length.
+ * * for each tuple frozen by the freeze plans: the offset of the item corresponding to that tuple
+ * The total number of OffsetNumbers is therefore
+ * (2*nredirected) + ndead + nunused + (sum[plan.ntuples for plan in plans])
*
* Acquires a full cleanup lock.
*/
typedef struct xl_heap_prune
{
TransactionId snapshotConflictHorizon;
+ uint16 nplans;
uint16 nredirected;
uint16 ndead;
+ uint16 nunused;
bool isCatalogRel; /* to handle recovery conflict during logical
* decoding on standby */
- /* OFFSET NUMBERS are in the block reference 0 */
+ /*
+ * OFFSET NUMBERS and freeze plans are in the block reference 0 in the
+ * following order:
+ *
+ * * xl_heap_freeze_plan plans[nplans];
+ * * OffsetNumber redirected[2 * nredirected];
+ * * OffsetNumber nowdead[ndead];
+ * * OffsetNumber nowunused[nunused];
+ * * OffsetNumber frz_offsets[...];
+ */
} xl_heap_prune;
#define SizeOfHeapPrune (offsetof(xl_heap_prune, isCatalogRel) + sizeof(bool))
--
2.40.1
--racicctn4wry6xe5
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0013-Set-hastup-in-heap_page_prune.patch"
^ permalink raw reply [nested|flat] 15+ messages in thread
* [PATCH v4 13/19] Merge prune and freeze records
@ 2024-01-07 22:55 Melanie Plageman <[email protected]>
0 siblings, 0 replies; 15+ messages in thread
From: Melanie Plageman @ 2024-01-07 22:55 UTC (permalink / raw)
Eliminate xl_heap_freeze and XLOG_HEAP2_FREEZE record. When vacuum
freezes tuples, the information needed to replay those changes is
now recorded in the xl_heap_prune record.
When both pruning and freezing is done, this means a single, combined
WAL record is emitted for both operations. This will reduce the number
of WAL records emitted.
When there are only tuples to freeze present, we can avoid taking a full
cleanup lock when replaying the record.
The XLOG_HEAP2_PRUNE record is now bigger than it was previously and
bigger than the XLOG_HEAP2_FREEZE record. A future commit will
streamline the record.
---
src/backend/access/heap/heapam.c | 146 ++++------
src/backend/access/heap/pruneheap.c | 326 ++++++++++++-----------
src/backend/access/rmgrdesc/heapdesc.c | 95 ++++---
src/backend/replication/logical/decode.c | 1 -
src/include/access/heapam_xlog.h | 97 ++++---
5 files changed, 318 insertions(+), 347 deletions(-)
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index e47b56e7856..532868039d5 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -8706,8 +8706,6 @@ ExtractReplicaIdentity(Relation relation, HeapTuple tp, bool key_required,
/*
* Handles XLOG_HEAP2_PRUNE record type.
- *
- * Acquires a full cleanup lock.
*/
static void
heap_xlog_prune(XLogReaderState *record)
@@ -8718,12 +8716,22 @@ heap_xlog_prune(XLogReaderState *record)
RelFileLocator rlocator;
BlockNumber blkno;
XLogRedoAction action;
+ bool get_cleanup_lock;
XLogRecGetBlockTag(record, 0, &rlocator, NULL, &blkno);
/*
- * We're about to remove tuples. In Hot Standby mode, ensure that there's
- * no queries running for which the removed tuples are still visible.
+ * If there are dead, redirected, or unused items set unused by
+ * heap_page_prune_and_freeze(), heap_page_prune_execute() will call
+ * PageRepairFragementation() which expects a full cleanup lock.
+ */
+ get_cleanup_lock = xlrec->nredirected > 0 ||
+ xlrec->ndead > 0 || xlrec->nunused > 0;
+
+ /*
+ * We are either about to remove tuples or freeze them. In Hot Standby
+ * mode, ensure that there's no queries running for which any removed
+ * tuples are still visible or which consider the frozen xids as running.
*/
if (InHotStandby)
ResolveRecoveryConflictWithSnapshot(xlrec->snapshotConflictHorizon,
@@ -8731,38 +8739,69 @@ heap_xlog_prune(XLogReaderState *record)
rlocator);
/*
- * If we have a full-page image, restore it (using a cleanup lock) and
- * we're done.
+ * If we have a full-page image, restore it and we're done.
*/
- action = XLogReadBufferForRedoExtended(record, 0, RBM_NORMAL, true,
- &buffer);
+ action = XLogReadBufferForRedoExtended(record, 0, RBM_NORMAL,
+ get_cleanup_lock, &buffer);
+
if (action == BLK_NEEDS_REDO)
{
Page page = (Page) BufferGetPage(buffer);
- OffsetNumber *end;
OffsetNumber *redirected;
OffsetNumber *nowdead;
OffsetNumber *nowunused;
int nredirected;
int ndead;
int nunused;
+ int nplans;
Size datalen;
+ xl_heap_freeze_plan *plans;
+ OffsetNumber *frz_offsets;
+ int curoff = 0;
- redirected = (OffsetNumber *) XLogRecGetBlockData(record, 0, &datalen);
-
+ nplans = xlrec->nplans;
nredirected = xlrec->nredirected;
ndead = xlrec->ndead;
- end = (OffsetNumber *) ((char *) redirected + datalen);
+ nunused = xlrec->nunused;
+
+ plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, &datalen);
+ redirected = (OffsetNumber *) &plans[nplans];
nowdead = redirected + (nredirected * 2);
nowunused = nowdead + ndead;
- nunused = (end - nowunused);
- Assert(nunused >= 0);
+ frz_offsets = nowunused + nunused;
/* Update all line pointers per the record, and repair fragmentation */
- heap_page_prune_execute(buffer,
- redirected, nredirected,
- nowdead, ndead,
- nowunused, nunused);
+ if (nredirected > 0 || ndead > 0 || nunused > 0)
+ heap_page_prune_execute(buffer,
+ redirected, nredirected,
+ nowdead, ndead,
+ nowunused, nunused);
+
+ for (int p = 0; p < nplans; p++)
+ {
+ HeapTupleFreeze frz;
+
+ /*
+ * Convert freeze plan representation from WAL record into
+ * per-tuple format used by heap_execute_freeze_tuple
+ */
+ frz.xmax = plans[p].xmax;
+ frz.t_infomask2 = plans[p].t_infomask2;
+ frz.t_infomask = plans[p].t_infomask;
+ frz.frzflags = plans[p].frzflags;
+ frz.offset = InvalidOffsetNumber; /* unused, but be tidy */
+
+ for (int i = 0; i < plans[p].ntuples; i++)
+ {
+ OffsetNumber offset = frz_offsets[curoff++];
+ ItemId lp;
+ HeapTupleHeader tuple;
+
+ lp = PageGetItemId(page, offset);
+ tuple = (HeapTupleHeader) PageGetItem(page, lp);
+ heap_execute_freeze_tuple(tuple, &frz);
+ }
+ }
/*
* Note: we don't worry about updating the page's prunability hints.
@@ -9001,74 +9040,6 @@ heap_xlog_visible(XLogReaderState *record)
UnlockReleaseBuffer(vmbuffer);
}
-/*
- * Replay XLOG_HEAP2_FREEZE_PAGE records
- */
-static void
-heap_xlog_freeze_page(XLogReaderState *record)
-{
- XLogRecPtr lsn = record->EndRecPtr;
- xl_heap_freeze_page *xlrec = (xl_heap_freeze_page *) XLogRecGetData(record);
- Buffer buffer;
-
- /*
- * In Hot Standby mode, ensure that there's no queries running which still
- * consider the frozen xids as running.
- */
- if (InHotStandby)
- {
- RelFileLocator rlocator;
-
- XLogRecGetBlockTag(record, 0, &rlocator, NULL, NULL);
- ResolveRecoveryConflictWithSnapshot(xlrec->snapshotConflictHorizon,
- xlrec->isCatalogRel,
- rlocator);
- }
-
- if (XLogReadBufferForRedo(record, 0, &buffer) == BLK_NEEDS_REDO)
- {
- Page page = BufferGetPage(buffer);
- xl_heap_freeze_plan *plans;
- OffsetNumber *offsets;
- int curoff = 0;
-
- plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, NULL);
- offsets = (OffsetNumber *) ((char *) plans +
- (xlrec->nplans *
- sizeof(xl_heap_freeze_plan)));
- for (int p = 0; p < xlrec->nplans; p++)
- {
- HeapTupleFreeze frz;
-
- /*
- * Convert freeze plan representation from WAL record into
- * per-tuple format used by heap_execute_freeze_tuple
- */
- frz.xmax = plans[p].xmax;
- frz.t_infomask2 = plans[p].t_infomask2;
- frz.t_infomask = plans[p].t_infomask;
- frz.frzflags = plans[p].frzflags;
- frz.offset = InvalidOffsetNumber; /* unused, but be tidy */
-
- for (int i = 0; i < plans[p].ntuples; i++)
- {
- OffsetNumber offset = offsets[curoff++];
- ItemId lp;
- HeapTupleHeader tuple;
-
- lp = PageGetItemId(page, offset);
- tuple = (HeapTupleHeader) PageGetItem(page, lp);
- heap_execute_freeze_tuple(tuple, &frz);
- }
- }
-
- PageSetLSN(page, lsn);
- MarkBufferDirty(buffer);
- }
- if (BufferIsValid(buffer))
- UnlockReleaseBuffer(buffer);
-}
-
/*
* Given an "infobits" field from an XLog record, set the correct bits in the
* given infomask and infomask2 for the tuple touched by the record.
@@ -9975,9 +9946,6 @@ heap2_redo(XLogReaderState *record)
case XLOG_HEAP2_VACUUM:
heap_xlog_vacuum(record);
break;
- case XLOG_HEAP2_FREEZE_PAGE:
- heap_xlog_freeze_page(record);
- break;
case XLOG_HEAP2_VISIBLE:
heap_xlog_visible(record);
break;
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index 7bd479cfd4e..19b50931b90 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -79,6 +79,9 @@ static void heap_prune_record_dead_or_unused(PruneState *prstate, OffsetNumber o
static void heap_prune_record_unused(PruneState *prstate, OffsetNumber offnum);
static void page_verify_redirects(Page page);
+static void log_heap_prune_and_freeze(Relation relation, Buffer buffer,
+ PruneState *prstate, PruneFreezeResult *presult);
+
/*
* Optionally prune and repair fragmentation in the specified page.
@@ -247,9 +250,9 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
HeapTupleData tup;
bool do_freeze;
bool do_prune;
+ bool do_hint;
bool whole_page_freezable;
bool hint_bit_fpi;
- bool prune_fpi = false;
int64 fpi_before = pgWalUsage.wal_fpi;
/*
@@ -445,10 +448,9 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
/*
* If checksums are enabled, heap_prune_satisfies_vacuum() may have caused
- * an FPI to be emitted. Then reset fpi_before for no prune case.
+ * an FPI to be emitted.
*/
hint_bit_fpi = fpi_before != pgWalUsage.wal_fpi;
- fpi_before = pgWalUsage.wal_fpi;
/*
* For vacuum, if the whole page will become frozen, we consider
@@ -498,14 +500,18 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
prstate.ndead > 0 ||
prstate.nunused > 0;
+ /* Record number of newly-set-LP_DEAD items for caller */
+ presult->nnewlpdead = prstate.ndead;
+
/*
- * Only incur overhead of checking if we will do an FPI if we might use
- * the information.
+ * Even if we don't prune anything, if we found a new value for the
+ * pd_prune_xid field or the page was marked full, we will update the hint
+ * bit.
*/
- if (do_prune && pagefrz)
- prune_fpi = XLogCheckBufferNeedsBackup(buffer);
+ do_hint = ((PageHeader) page)->pd_prune_xid != prstate.new_prune_xid ||
+ PageIsFull(page);
- /* Is the whole page freezable? And is there something to freeze */
+ /* Is the whole page freezable? And is there something to freeze? */
whole_page_freezable = presult->all_visible_except_removable &&
presult->all_frozen;
@@ -520,43 +526,51 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
* opportunistic freeze heuristic must be improved; however, for now, try
* to approximate it.
*/
- do_freeze = pagefrz &&
- (pagefrz->freeze_required ||
- (whole_page_freezable && presult->nfrozen > 0 && (prune_fpi || hint_bit_fpi)));
+ do_freeze = false;
+ if (pagefrz)
+ {
+ if (pagefrz->freeze_required)
+ do_freeze = true;
+ else if (whole_page_freezable && presult->nfrozen > 0)
+ {
+ /*
+ * Freezing would make the page all-frozen. In this case, we will
+ * freeze if we have already emitted an FPI or will do so anyway.
+ * Be sure only to incur the overhead of checking if we will do an
+ * FPI if we may use that information.
+ */
+ if (hint_bit_fpi ||
+ ((do_prune || do_hint) && XLogCheckBufferNeedsBackup(buffer)))
+ {
+ do_freeze = true;
+ }
+ }
+ }
+ /*
+ * Validate the tuples we are considering freezing. We do this even if
+ * pruning and hint bit setting have not emitted an FPI so far because we
+ * still may emit an FPI while setting the page hint bit later. But we
+ * want to avoid doing the pre-freeze checks in a critical section.
+ */
if (do_freeze)
- {
heap_pre_freeze_checks(buffer, prstate.frozen, presult->nfrozen);
+ if (!do_freeze && (!pagefrz || !presult->all_frozen || presult->nfrozen > 0))
+ {
/*
- * We can use frz_conflict_horizon as our cutoff for conflicts when
- * the whole page is eligible to become all-frozen in the VM once
- * we're done with it. Otherwise we generate a conservative cutoff by
- * stepping back from OldestXmin.
+ * If we will neither freeze tuples on the page nor set the page all
+ * frozen in the visibility map, the page is not all-frozen and there
+ * will be no newly frozen tuples.
*/
- if (!(presult->all_visible_except_removable && presult->all_frozen))
- {
- /* Avoids false conflicts when hot_standby_feedback in use */
- presult->frz_conflict_horizon = pagefrz->cutoffs->OldestXmin;
- TransactionIdRetreat(presult->frz_conflict_horizon);
- }
+ presult->all_frozen = false;
+ presult->nfrozen = 0; /* avoid miscounts in instrumentation */
}
- /* Any error while applying the changes is critical */
START_CRIT_SECTION();
- /* Have we found any prunable items? */
- if (do_prune)
+ if (do_hint)
{
- /*
- * Apply the planned item changes, then repair page fragmentation, and
- * update the page's hint bit about whether it has free line pointers.
- */
- heap_page_prune_execute(buffer,
- prstate.redirected, prstate.nredirected,
- prstate.nowdead, prstate.ndead,
- prstate.nowunused, prstate.nunused);
-
/*
* Update the page's pd_prune_xid field to either zero, or the lowest
* XID of any soon-prunable tuple.
@@ -564,163 +578,159 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
((PageHeader) page)->pd_prune_xid = prstate.new_prune_xid;
/*
- * Also clear the "page is full" flag, since there's no point in
- * repeating the prune/defrag process until something else happens to
- * the page.
+ * Clear the "page is full" flag if it is set since there's no point
+ * in repeating the prune/defrag process until something else happens
+ * to the page.
*/
PageClearFull(page);
- MarkBufferDirty(buffer);
+ /*
+ * We only needed to update pd_prune_xid and clear the page-is-full
+ * hint bit, this is a non-WAL-logged hint. If we will also freeze or
+ * prune the page, we will mark the buffer dirty below.
+ */
+ if (!do_freeze && !do_prune)
+ MarkBufferDirtyHint(buffer, true);
+ }
+ if (do_prune || do_freeze)
+ {
/*
- * Emit a WAL XLOG_HEAP2_PRUNE record showing what we did
+ * Apply the planned item changes, then repair page fragmentation, and
+ * update the page's hint bit about whether it has free line pointers.
*/
- if (RelationNeedsWAL(relation))
+ if (do_prune)
{
- xl_heap_prune xlrec;
- XLogRecPtr recptr;
-
- xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
- xlrec.snapshotConflictHorizon = prstate.snapshotConflictHorizon;
- xlrec.nredirected = prstate.nredirected;
- xlrec.ndead = prstate.ndead;
-
- XLogBeginInsert();
- XLogRegisterData((char *) &xlrec, SizeOfHeapPrune);
-
- XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
+ heap_page_prune_execute(buffer,
+ prstate.redirected, prstate.nredirected,
+ prstate.nowdead, prstate.ndead,
+ prstate.nowunused, prstate.nunused);
+ }
+ if (do_freeze)
+ {
/*
- * The OffsetNumber arrays are not actually in the buffer, but we
- * pretend that they are. When XLogInsert stores the whole
- * buffer, the offset arrays need not be stored too.
+ * We can use frz_conflict_horizon as our cutoff for conflicts
+ * when the whole page is eligible to become all-frozen in the VM
+ * once we're done with it. Otherwise we generate a conservative
+ * cutoff by stepping back from OldestXmin. This avoids false
+ * conflicts when hot_standby_feedback is in use.
*/
- if (prstate.nredirected > 0)
- XLogRegisterBufData(0, (char *) prstate.redirected,
- prstate.nredirected *
- sizeof(OffsetNumber) * 2);
-
- if (prstate.ndead > 0)
- XLogRegisterBufData(0, (char *) prstate.nowdead,
- prstate.ndead * sizeof(OffsetNumber));
-
- if (prstate.nunused > 0)
- XLogRegisterBufData(0, (char *) prstate.nowunused,
- prstate.nunused * sizeof(OffsetNumber));
+ if (!(presult->all_visible_except_removable && presult->all_frozen))
+ {
+ presult->frz_conflict_horizon = pagefrz->cutoffs->OldestXmin;
+ TransactionIdRetreat(presult->frz_conflict_horizon);
+ }
+ heap_freeze_prepared_tuples(buffer, prstate.frozen, presult->nfrozen);
+ }
- recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
+ MarkBufferDirty(buffer);
- PageSetLSN(BufferGetPage(buffer), recptr);
- }
- }
- else
- {
/*
- * If we didn't prune anything, but have found a new value for the
- * pd_prune_xid field, update it and mark the buffer dirty. This is
- * treated as a non-WAL-logged hint.
- *
- * Also clear the "page is full" flag if it is set, since there's no
- * point in repeating the prune/defrag process until something else
- * happens to the page.
+ * Emit a WAL XLOG_HEAP2_PRUNE record showing what we did
*/
- if (((PageHeader) page)->pd_prune_xid != prstate.new_prune_xid ||
- PageIsFull(page))
- {
- ((PageHeader) page)->pd_prune_xid = prstate.new_prune_xid;
- PageClearFull(page);
- MarkBufferDirtyHint(buffer, true);
- }
+ if (RelationNeedsWAL(relation))
+ log_heap_prune_and_freeze(relation, buffer, &prstate, presult);
}
END_CRIT_SECTION();
- /* Record number of newly-set-LP_DEAD items for caller */
- presult->nnewlpdead = prstate.ndead;
-
- if (do_freeze)
+ /*
+ * If we froze tuples on the page, the caller can advance relfrozenxid and
+ * relminmxid to the values in pagefrz->FreezePageRelfrozenXid and
+ * pagefrz->FreezePageRelminMxid. Otherwise, it is only safe to advance to
+ * the values in pagefrz->NoFreezePage[RelfrozenXid|RelminMxid]
+ */
+ if (pagefrz)
{
- START_CRIT_SECTION();
+ if (presult->nfrozen > 0)
+ {
+ presult->new_relfrozenxid = pagefrz->FreezePageRelfrozenXid;
+ presult->new_relminmxid = pagefrz->FreezePageRelminMxid;
+ }
+ else
+ {
+ presult->new_relfrozenxid = pagefrz->NoFreezePageRelfrozenXid;
+ presult->new_relminmxid = pagefrz->NoFreezePageRelminMxid;
+ }
+ }
+}
- Assert(presult->nfrozen > 0);
- heap_freeze_prepared_tuples(buffer, prstate.frozen, presult->nfrozen);
+static void
+log_heap_prune_and_freeze(Relation relation, Buffer buffer,
+ PruneState *prstate, PruneFreezeResult *presult)
+{
+ xl_heap_prune xlrec;
+ XLogRecPtr recptr;
- MarkBufferDirty(buffer);
+ xl_heap_freeze_plan plans[MaxHeapTuplesPerPage];
+ OffsetNumber offsets[MaxHeapTuplesPerPage];
+ bool do_freeze = presult->nfrozen > 0;
- /* Now WAL-log freezing if necessary */
- if (RelationNeedsWAL(relation))
- {
- xl_heap_freeze_plan plans[MaxHeapTuplesPerPage];
- OffsetNumber offsets[MaxHeapTuplesPerPage];
- int nplans;
- xl_heap_freeze_page xlrec;
- XLogRecPtr recptr;
+ xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
+ xlrec.nredirected = prstate->nredirected;
+ xlrec.ndead = prstate->ndead;
+ xlrec.nunused = prstate->nunused;
+ xlrec.nplans = 0;
- /*
- * Prepare deduplicated representation for use in WAL record
- * Destructively sorts tuples array in-place.
- */
- nplans = heap_log_freeze_plan(prstate.frozen, presult->nfrozen, plans, offsets);
+ /*
+ * The snapshotConflictHorizon for the whole record should be the most
+ * conservative of all the horizons calculated for any of the possible
+ * modifications. If this record will prune tuples, any transactions on
+ * the standby older than the youngest xmax of the most recently removed
+ * tuple this record will prune will conflict. If this record will freeze
+ * tuples, any transactions on the standby with xids older than the
+ * youngest tuple this record will freeze will conflict.
+ */
+ if (do_freeze)
+ xlrec.snapshotConflictHorizon = Max(prstate->snapshotConflictHorizon,
+ presult->frz_conflict_horizon);
+ else
+ xlrec.snapshotConflictHorizon = prstate->snapshotConflictHorizon;
- xlrec.snapshotConflictHorizon = presult->frz_conflict_horizon;
- xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
- xlrec.nplans = nplans;
+ /*
+ * Prepare deduplicated representation for use in WAL record Destructively
+ * sorts tuples array in-place.
+ */
+ if (do_freeze)
+ xlrec.nplans = heap_log_freeze_plan(prstate->frozen,
+ presult->nfrozen, plans, offsets);
- XLogBeginInsert();
- XLogRegisterData((char *) &xlrec, SizeOfHeapFreezePage);
+ XLogBeginInsert();
+ XLogRegisterData((char *) &xlrec, SizeOfHeapPrune);
- /*
- * The freeze plan array and offset array are not actually in the
- * buffer, but pretend that they are. When XLogInsert stores the
- * whole buffer, the arrays need not be stored too.
- */
- XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
- XLogRegisterBufData(0, (char *) plans,
- nplans * sizeof(xl_heap_freeze_plan));
- XLogRegisterBufData(0, (char *) offsets,
- presult->nfrozen * sizeof(OffsetNumber));
+ XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
- recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_FREEZE_PAGE);
+ /*
+ * The OffsetNumber arrays are not actually in the buffer, but we pretend
+ * that they are. When XLogInsert stores the whole buffer, the offset
+ * arrays need not be stored too.
+ */
+ if (xlrec.nplans > 0)
+ XLogRegisterBufData(0, (char *) plans,
+ xlrec.nplans * sizeof(xl_heap_freeze_plan));
- PageSetLSN(page, recptr);
- }
+ if (prstate->nredirected > 0)
+ XLogRegisterBufData(0, (char *) prstate->redirected,
+ prstate->nredirected *
+ sizeof(OffsetNumber) * 2);
- END_CRIT_SECTION();
- }
- else if (!pagefrz || !presult->all_frozen || presult->nfrozen > 0)
- {
- /*
- * If we will neither freeze tuples on the page nor set the page all
- * frozen in the visibility map, the page is not all frozen and there
- * will be no newly frozen tuples.
- */
- presult->all_frozen = false;
- presult->nfrozen = 0; /* avoid miscounts in instrumentation */
- }
+ if (prstate->ndead > 0)
+ XLogRegisterBufData(0, (char *) prstate->nowdead,
+ prstate->ndead * sizeof(OffsetNumber));
- /* Caller won't update new_relfrozenxid and new_relminmxid */
- if (!pagefrz)
- return;
+ if (prstate->nunused > 0)
+ XLogRegisterBufData(0, (char *) prstate->nowunused,
+ prstate->nunused * sizeof(OffsetNumber));
+ if (xlrec.nplans > 0)
+ XLogRegisterBufData(0, (char *) offsets,
+ presult->nfrozen * sizeof(OffsetNumber));
- /*
- * If we will freeze tuples on the page or, even if we don't freeze tuples
- * on the page, if we will set the page all-frozen in the visibility map,
- * we can advance relfrozenxid and relminmxid to the values in
- * pagefrz->FreezePageRelfrozenXid and pagefrz->FreezePageRelminMxid.
- */
- if (presult->all_frozen || presult->nfrozen > 0)
- {
- presult->new_relfrozenxid = pagefrz->FreezePageRelfrozenXid;
- presult->new_relminmxid = pagefrz->FreezePageRelminMxid;
- }
- else
- {
- presult->new_relfrozenxid = pagefrz->NoFreezePageRelfrozenXid;
- presult->new_relminmxid = pagefrz->NoFreezePageRelminMxid;
- }
-}
+ recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
+ PageSetLSN(BufferGetPage(buffer), recptr);
+}
/*
* Perform visibility checks for heap pruning.
diff --git a/src/backend/access/rmgrdesc/heapdesc.c b/src/backend/access/rmgrdesc/heapdesc.c
index 36a3d83c8c2..9f0a0341d40 100644
--- a/src/backend/access/rmgrdesc/heapdesc.c
+++ b/src/backend/access/rmgrdesc/heapdesc.c
@@ -179,43 +179,67 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
{
xl_heap_prune *xlrec = (xl_heap_prune *) rec;
- appendStringInfo(buf, "snapshotConflictHorizon: %u, nredirected: %u, ndead: %u, isCatalogRel: %c",
+ appendStringInfo(buf, "snapshotConflictHorizon: %u, isCatalogRel: %c",
xlrec->snapshotConflictHorizon,
- xlrec->nredirected,
- xlrec->ndead,
xlrec->isCatalogRel ? 'T' : 'F');
if (XLogRecHasBlockData(record, 0))
{
- OffsetNumber *end;
OffsetNumber *redirected;
OffsetNumber *nowdead;
OffsetNumber *nowunused;
int nredirected;
+ int ndead;
int nunused;
+ int nplans;
Size datalen;
+ xl_heap_freeze_plan *plans;
+ OffsetNumber *frz_offsets;
- redirected = (OffsetNumber *) XLogRecGetBlockData(record, 0,
- &datalen);
-
+ nplans = xlrec->nplans;
nredirected = xlrec->nredirected;
- end = (OffsetNumber *) ((char *) redirected + datalen);
- nowdead = redirected + (nredirected * 2);
- nowunused = nowdead + xlrec->ndead;
- nunused = (end - nowunused);
- Assert(nunused >= 0);
+ ndead = xlrec->ndead;
+ nunused = xlrec->nunused;
- appendStringInfo(buf, ", nunused: %d", nunused);
-
- appendStringInfoString(buf, ", redirected:");
- array_desc(buf, redirected, sizeof(OffsetNumber) * 2,
- nredirected, &redirect_elem_desc, NULL);
- appendStringInfoString(buf, ", dead:");
- array_desc(buf, nowdead, sizeof(OffsetNumber), xlrec->ndead,
- &offset_elem_desc, NULL);
- appendStringInfoString(buf, ", unused:");
- array_desc(buf, nowunused, sizeof(OffsetNumber), nunused,
- &offset_elem_desc, NULL);
+ plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, &datalen);
+ redirected = (OffsetNumber *) &plans[nplans];
+ nowdead = redirected + (nredirected * 2);
+ nowunused = nowdead + ndead;
+ frz_offsets = nowunused + nunused;
+
+ appendStringInfo(buf, ", nredirected: %u, ndead: %u, nunused: %u, nplans: %u,",
+ nredirected,
+ ndead,
+ nunused,
+ nplans);
+
+ if (nredirected > 0)
+ {
+ appendStringInfoString(buf, ", redirected:");
+ array_desc(buf, redirected, sizeof(OffsetNumber) * 2,
+ nredirected, &redirect_elem_desc, NULL);
+ }
+
+ if (ndead > 0)
+ {
+ appendStringInfoString(buf, ", dead:");
+ array_desc(buf, nowdead, sizeof(OffsetNumber), ndead,
+ &offset_elem_desc, NULL);
+ }
+
+ if (nunused > 0)
+ {
+ appendStringInfoString(buf, ", unused:");
+ array_desc(buf, nowunused, sizeof(OffsetNumber), nunused,
+ &offset_elem_desc, NULL);
+ }
+
+ if (nplans > 0)
+ {
+ appendStringInfoString(buf, ", plans:");
+ array_desc(buf, plans, sizeof(xl_heap_freeze_plan), nplans,
+ &plan_elem_desc, &frz_offsets);
+ }
}
}
else if (info == XLOG_HEAP2_VACUUM)
@@ -235,28 +259,6 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
&offset_elem_desc, NULL);
}
}
- else if (info == XLOG_HEAP2_FREEZE_PAGE)
- {
- xl_heap_freeze_page *xlrec = (xl_heap_freeze_page *) rec;
-
- appendStringInfo(buf, "snapshotConflictHorizon: %u, nplans: %u, isCatalogRel: %c",
- xlrec->snapshotConflictHorizon, xlrec->nplans,
- xlrec->isCatalogRel ? 'T' : 'F');
-
- if (XLogRecHasBlockData(record, 0))
- {
- xl_heap_freeze_plan *plans;
- OffsetNumber *offsets;
-
- plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, NULL);
- offsets = (OffsetNumber *) ((char *) plans +
- (xlrec->nplans *
- sizeof(xl_heap_freeze_plan)));
- appendStringInfoString(buf, ", plans:");
- array_desc(buf, plans, sizeof(xl_heap_freeze_plan), xlrec->nplans,
- &plan_elem_desc, &offsets);
- }
- }
else if (info == XLOG_HEAP2_VISIBLE)
{
xl_heap_visible *xlrec = (xl_heap_visible *) rec;
@@ -361,9 +363,6 @@ heap2_identify(uint8 info)
case XLOG_HEAP2_VACUUM:
id = "VACUUM";
break;
- case XLOG_HEAP2_FREEZE_PAGE:
- id = "FREEZE_PAGE";
- break;
case XLOG_HEAP2_VISIBLE:
id = "VISIBLE";
break;
diff --git a/src/backend/replication/logical/decode.c b/src/backend/replication/logical/decode.c
index e5ab7b78b78..f77051572fd 100644
--- a/src/backend/replication/logical/decode.c
+++ b/src/backend/replication/logical/decode.c
@@ -445,7 +445,6 @@ heap2_decode(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
* Everything else here is just low level physical stuff we're not
* interested in.
*/
- case XLOG_HEAP2_FREEZE_PAGE:
case XLOG_HEAP2_PRUNE:
case XLOG_HEAP2_VACUUM:
case XLOG_HEAP2_VISIBLE:
diff --git a/src/include/access/heapam_xlog.h b/src/include/access/heapam_xlog.h
index 6488dad5e64..fe4a8ff0620 100644
--- a/src/include/access/heapam_xlog.h
+++ b/src/include/access/heapam_xlog.h
@@ -53,11 +53,10 @@
#define XLOG_HEAP2_REWRITE 0x00
#define XLOG_HEAP2_PRUNE 0x10
#define XLOG_HEAP2_VACUUM 0x20
-#define XLOG_HEAP2_FREEZE_PAGE 0x30
-#define XLOG_HEAP2_VISIBLE 0x40
-#define XLOG_HEAP2_MULTI_INSERT 0x50
-#define XLOG_HEAP2_LOCK_UPDATED 0x60
-#define XLOG_HEAP2_NEW_CID 0x70
+#define XLOG_HEAP2_VISIBLE 0x30
+#define XLOG_HEAP2_MULTI_INSERT 0x40
+#define XLOG_HEAP2_LOCK_UPDATED 0x50
+#define XLOG_HEAP2_NEW_CID 0x60
/*
* xl_heap_insert/xl_heap_multi_insert flag values, 8 bits are available.
@@ -226,28 +225,65 @@ typedef struct xl_heap_update
#define SizeOfHeapUpdate (offsetof(xl_heap_update, new_offnum) + sizeof(OffsetNumber))
+/*
+ * This struct represents a 'freeze plan', which describes how to freeze a
+ * group of one or more heap tuples (appears in xl_heap_prune record)
+ */
+/* 0x01 was XLH_FREEZE_XMIN */
+#define XLH_FREEZE_XVAC 0x02
+#define XLH_INVALID_XVAC 0x04
+
+typedef struct xl_heap_freeze_plan
+{
+ TransactionId xmax;
+ uint16 t_infomask2;
+ uint16 t_infomask;
+ uint8 frzflags;
+
+ /* Length of individual page offset numbers array for this plan */
+ uint16 ntuples;
+} xl_heap_freeze_plan;
+
+/*
+ * As of Postgres 17, XLOG_HEAP2_PRUNE records replace
+ * XLOG_HEAP2_FREEZE_PAGE records.
+ */
+
/*
* This is what we need to know about page pruning (both during VACUUM and
* during opportunistic pruning)
*
* The array of OffsetNumbers following the fixed part of the record contains:
+ * * for each freeze plan: the freeze plan
* * for each redirected item: the item offset, then the offset redirected to
* * for each now-dead item: the item offset
* * for each now-unused item: the item offset
- * The total number of OffsetNumbers is therefore 2*nredirected+ndead+nunused.
- * Note that nunused is not explicitly stored, but may be found by reference
- * to the total record length.
+ * * for each tuple frozen by the freeze plans: the offset of the item corresponding to that tuple
+ * The total number of OffsetNumbers is therefore
+ * (2*nredirected) + ndead + nunused + (sum[plan.ntuples for plan in plans])
*
- * Acquires a full cleanup lock.
+ * Acquires a full cleanup lock if heap_page_prune_execute() must be called
*/
typedef struct xl_heap_prune
{
TransactionId snapshotConflictHorizon;
+ uint16 nplans;
uint16 nredirected;
uint16 ndead;
+ uint16 nunused;
bool isCatalogRel; /* to handle recovery conflict during logical
* decoding on standby */
- /* OFFSET NUMBERS are in the block reference 0 */
+ /*--------------------------------------------------------------------
+ * OFFSET NUMBERS and freeze plans are in the block reference 0 in the
+ * following order:
+ *
+ * * xl_heap_freeze_plan plans[nplans];
+ * * OffsetNumber redirected[2 * nredirected];
+ * * OffsetNumber nowdead[ndead];
+ * * OffsetNumber nowunused[nunused];
+ * * OffsetNumber frz_offsets[...];
+ *--------------------------------------------------------------------
+ */
} xl_heap_prune;
#define SizeOfHeapPrune (offsetof(xl_heap_prune, isCatalogRel) + sizeof(bool))
@@ -315,47 +351,6 @@ typedef struct xl_heap_inplace
#define SizeOfHeapInplace (offsetof(xl_heap_inplace, offnum) + sizeof(OffsetNumber))
-/*
- * This struct represents a 'freeze plan', which describes how to freeze a
- * group of one or more heap tuples (appears in xl_heap_freeze_page record)
- */
-/* 0x01 was XLH_FREEZE_XMIN */
-#define XLH_FREEZE_XVAC 0x02
-#define XLH_INVALID_XVAC 0x04
-
-typedef struct xl_heap_freeze_plan
-{
- TransactionId xmax;
- uint16 t_infomask2;
- uint16 t_infomask;
- uint8 frzflags;
-
- /* Length of individual page offset numbers array for this plan */
- uint16 ntuples;
-} xl_heap_freeze_plan;
-
-/*
- * This is what we need to know about a block being frozen during vacuum
- *
- * Backup block 0's data contains an array of xl_heap_freeze_plan structs
- * (with nplans elements), followed by one or more page offset number arrays.
- * Each such page offset number array corresponds to a single freeze plan
- * (REDO routine freezes corresponding heap tuples using freeze plan).
- */
-typedef struct xl_heap_freeze_page
-{
- TransactionId snapshotConflictHorizon;
- uint16 nplans;
- bool isCatalogRel; /* to handle recovery conflict during logical
- * decoding on standby */
-
- /*
- * In payload of blk 0 : FREEZE PLANS and OFFSET NUMBER ARRAY
- */
-} xl_heap_freeze_page;
-
-#define SizeOfHeapFreezePage (offsetof(xl_heap_freeze_page, isCatalogRel) + sizeof(bool))
-
/*
* This is what we need to know about setting a visibility map bit
*
--
2.40.1
--tez7m2a73jtztiij
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0014-Vacuum-second-pass-emits-XLOG_HEAP2_PRUNE-record.patch"
^ permalink raw reply [nested|flat] 15+ messages in thread
* [PATCH v2 12/17] Merge prune and freeze records
@ 2024-01-07 22:55 Melanie Plageman <[email protected]>
0 siblings, 0 replies; 15+ messages in thread
From: Melanie Plageman @ 2024-01-07 22:55 UTC (permalink / raw)
When there are both tuples to prune and freeze on a page, emit a single,
combined prune record containing the offsets for pruning and the freeze
plans and offsets for freezing. This will reduce the number of WAL
records emitted.
---
src/backend/access/heap/heapam.c | 42 ++++++++++++--
src/backend/access/heap/pruneheap.c | 85 +++++++++++++----------------
src/include/access/heapam_xlog.h | 20 +++++--
3 files changed, 90 insertions(+), 57 deletions(-)
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index a3691584c55..a8f35eba3c9 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -8803,24 +8803,28 @@ heap_xlog_prune(XLogReaderState *record)
if (action == BLK_NEEDS_REDO)
{
Page page = (Page) BufferGetPage(buffer);
- OffsetNumber *end;
OffsetNumber *redirected;
OffsetNumber *nowdead;
OffsetNumber *nowunused;
int nredirected;
int ndead;
int nunused;
+ int nplans;
Size datalen;
+ xl_heap_freeze_plan *plans;
+ OffsetNumber *frz_offsets;
+ int curoff = 0;
- redirected = (OffsetNumber *) XLogRecGetBlockData(record, 0, &datalen);
-
+ nplans = xlrec->nplans;
nredirected = xlrec->nredirected;
ndead = xlrec->ndead;
- end = (OffsetNumber *) ((char *) redirected + datalen);
+ nunused = xlrec->nunused;
+
+ plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, &datalen);
+ redirected = (OffsetNumber *) &plans[nplans];
nowdead = redirected + (nredirected * 2);
nowunused = nowdead + ndead;
- nunused = (end - nowunused);
- Assert(nunused >= 0);
+ frz_offsets = nowunused + nunused;
/* Update all line pointers per the record, and repair fragmentation */
heap_page_prune_execute(buffer,
@@ -8828,6 +8832,32 @@ heap_xlog_prune(XLogReaderState *record)
nowdead, ndead,
nowunused, nunused);
+ for (int p = 0; p < nplans; p++)
+ {
+ HeapTupleFreeze frz;
+
+ /*
+ * Convert freeze plan representation from WAL record into
+ * per-tuple format used by heap_execute_freeze_tuple
+ */
+ frz.xmax = plans[p].xmax;
+ frz.t_infomask2 = plans[p].t_infomask2;
+ frz.t_infomask = plans[p].t_infomask;
+ frz.frzflags = plans[p].frzflags;
+ frz.offset = InvalidOffsetNumber; /* unused, but be tidy */
+
+ for (int i = 0; i < plans[p].ntuples; i++)
+ {
+ OffsetNumber offset = frz_offsets[curoff++];
+ ItemId lp;
+ HeapTupleHeader tuple;
+
+ lp = PageGetItemId(page, offset);
+ tuple = (HeapTupleHeader) PageGetItem(page, lp);
+ heap_execute_freeze_tuple(tuple, &frz);
+ }
+ }
+
/*
* Note: we don't worry about updating the page's prunability hints.
* At worst this will cause an extra prune cycle to occur soon.
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index ca64c45d8a3..70d35a21e98 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -605,6 +605,9 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
*/
PageClearFull(page);
+ if (do_freeze)
+ heap_freeze_prepared_tuples(buffer, frozen, presult->nfrozen);
+
MarkBufferDirty(buffer);
/*
@@ -615,10 +618,37 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
xl_heap_prune xlrec;
XLogRecPtr recptr;
+ xl_heap_freeze_plan plans[MaxHeapTuplesPerPage];
+ OffsetNumber offsets[MaxHeapTuplesPerPage];
+
xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
- xlrec.snapshotConflictHorizon = prstate.snapshotConflictHorizon;
xlrec.nredirected = prstate.nredirected;
xlrec.ndead = prstate.ndead;
+ xlrec.nunused = prstate.nunused;
+ xlrec.nplans = 0;
+
+ /*
+ * The snapshotConflictHorizon for the whole record should be the most
+ * conservative of all the horizons calculated for any of the possible
+ * modifications. If this record will prune tuples, any transactions
+ * on the standby older than the youngest xmax of the most recently
+ * removed tuple this record will prune will conflict. If this record
+ * will freeze tuples, any transactions on the standby with xids older
+ * than the youngest tuple this record will freeze will conflict.
+ */
+ if (do_freeze)
+ xlrec.snapshotConflictHorizon = Max(prstate.snapshotConflictHorizon,
+ frz_conflict_horizon);
+ else
+ xlrec.snapshotConflictHorizon = prstate.snapshotConflictHorizon;
+
+ /*
+ * Prepare deduplicated representation for use in WAL record
+ * Destructively sorts tuples array in-place.
+ */
+ if (do_freeze)
+ xlrec.nplans = heap_log_freeze_plan(frozen,
+ presult->nfrozen, plans, offsets);
XLogBeginInsert();
XLogRegisterData((char *) &xlrec, SizeOfHeapPrune);
@@ -630,6 +660,10 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
* pretend that they are. When XLogInsert stores the whole buffer,
* the offset arrays need not be stored too.
*/
+ if (xlrec.nplans > 0)
+ XLogRegisterBufData(0, (char *) plans,
+ xlrec.nplans * sizeof(xl_heap_freeze_plan));
+
if (prstate.nredirected > 0)
XLogRegisterBufData(0, (char *) prstate.redirected,
prstate.nredirected *
@@ -643,56 +677,13 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
XLogRegisterBufData(0, (char *) prstate.nowunused,
prstate.nunused * sizeof(OffsetNumber));
- recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
-
- PageSetLSN(BufferGetPage(buffer), recptr);
- }
-
- if (do_freeze)
- {
- Assert(presult->nfrozen > 0);
-
- heap_freeze_prepared_tuples(buffer, frozen, presult->nfrozen);
-
- MarkBufferDirty(buffer);
-
- /* Now WAL-log freezing if necessary */
- if (RelationNeedsWAL(relation))
- {
- xl_heap_freeze_plan plans[MaxHeapTuplesPerPage];
- OffsetNumber offsets[MaxHeapTuplesPerPage];
- int nplans;
- xl_heap_freeze_page xlrec;
- XLogRecPtr recptr;
-
- /*
- * Prepare deduplicated representation for use in WAL record
- * Destructively sorts tuples array in-place.
- */
- nplans = heap_log_freeze_plan(frozen, presult->nfrozen, plans, offsets);
-
- xlrec.snapshotConflictHorizon = frz_conflict_horizon;
- xlrec.isCatalogRel = RelationIsAccessibleInLogicalDecoding(relation);
- xlrec.nplans = nplans;
-
- XLogBeginInsert();
- XLogRegisterData((char *) &xlrec, SizeOfHeapFreezePage);
-
- /*
- * The freeze plan array and offset array are not actually in the
- * buffer, but pretend that they are. When XLogInsert stores the
- * whole buffer, the arrays need not be stored too.
- */
- XLogRegisterBuffer(0, buffer, REGBUF_STANDARD);
- XLogRegisterBufData(0, (char *) plans,
- nplans * sizeof(xl_heap_freeze_plan));
+ if (xlrec.nplans > 0)
XLogRegisterBufData(0, (char *) offsets,
presult->nfrozen * sizeof(OffsetNumber));
- recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_FREEZE_PAGE);
+ recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_PRUNE);
- PageSetLSN(page, recptr);
- }
+ PageSetLSN(BufferGetPage(buffer), recptr);
}
END_CRIT_SECTION();
diff --git a/src/include/access/heapam_xlog.h b/src/include/access/heapam_xlog.h
index 6488dad5e64..22f236bb52a 100644
--- a/src/include/access/heapam_xlog.h
+++ b/src/include/access/heapam_xlog.h
@@ -231,23 +231,35 @@ typedef struct xl_heap_update
* during opportunistic pruning)
*
* The array of OffsetNumbers following the fixed part of the record contains:
+ * * for each freeze plan: the freeze plan
* * for each redirected item: the item offset, then the offset redirected to
* * for each now-dead item: the item offset
* * for each now-unused item: the item offset
- * The total number of OffsetNumbers is therefore 2*nredirected+ndead+nunused.
- * Note that nunused is not explicitly stored, but may be found by reference
- * to the total record length.
+ * * for each tuple frozen by the freeze plans: the offset of the item corresponding to that tuple
+ * The total number of OffsetNumbers is therefore
+ * (2*nredirected) + ndead + nunused + (sum[plan.ntuples for plan in plans])
*
* Acquires a full cleanup lock.
*/
typedef struct xl_heap_prune
{
TransactionId snapshotConflictHorizon;
+ uint16 nplans;
uint16 nredirected;
uint16 ndead;
+ uint16 nunused;
bool isCatalogRel; /* to handle recovery conflict during logical
* decoding on standby */
- /* OFFSET NUMBERS are in the block reference 0 */
+ /*
+ * OFFSET NUMBERS and freeze plans are in the block reference 0 in the
+ * following order:
+ *
+ * * xl_heap_freeze_plan plans[nplans];
+ * * OffsetNumber redirected[2 * nredirected];
+ * * OffsetNumber nowdead[ndead];
+ * * OffsetNumber nowunused[nunused];
+ * * OffsetNumber frz_offsets[...];
+ */
} xl_heap_prune;
#define SizeOfHeapPrune (offsetof(xl_heap_prune, isCatalogRel) + sizeof(bool))
--
2.40.1
--rdqtp5puvxqotfdw
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v2-0013-Set-hastup-in-heap_page_prune.patch"
^ permalink raw reply [nested|flat] 15+ messages in thread
* [PATCH v9 12/21] Merge prune and freeze records
@ 2024-03-26 13:37 Melanie Plageman <[email protected]>
0 siblings, 0 replies; 15+ messages in thread
From: Melanie Plageman @ 2024-03-26 13:37 UTC (permalink / raw)
When both pruning and freezing is done, this means a single, combined
WAL record is emitted for both operations. This will reduce the number
of WAL records emitted.
When there are only tuples to freeze present, we can avoid taking a full
cleanup lock when replaying the record.
---
src/backend/access/heap/heapam.c | 2 -
src/backend/access/heap/pruneheap.c | 215 +++++++++++++++-------------
2 files changed, 114 insertions(+), 103 deletions(-)
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 41c1c7d286f..aefc0be0dd3 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -6836,8 +6836,6 @@ heap_freeze_prepared_tuples(Buffer buffer, HeapTupleFreeze *tuples, int ntuples)
htup = (HeapTupleHeader) PageGetItem(page, itemid);
heap_execute_freeze_tuple(htup, frz);
}
-
- MarkBufferDirty(buffer);
}
/*
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index 5d8c881c2fc..6085fd1a8f9 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -249,9 +249,8 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
bool do_freeze;
bool all_visible_except_removable;
bool do_prune;
- bool whole_page_freezable;
+ bool do_hint;
bool hint_bit_fpi;
- bool prune_fpi = false;
int64 fpi_before = pgWalUsage.wal_fpi;
/*
@@ -464,10 +463,9 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
/*
* If checksums are enabled, heap_prune_satisfies_vacuum() may have caused
- * an FPI to be emitted. Then reset fpi_before for no prune case.
+ * an FPI to be emitted.
*/
hint_bit_fpi = fpi_before != pgWalUsage.wal_fpi;
- fpi_before = pgWalUsage.wal_fpi;
/*
* For vacuum, if the whole page will become frozen, we consider
@@ -517,16 +515,16 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
prstate.ndead > 0 ||
prstate.nunused > 0;
+ /* Record number of newly-set-LP_DEAD items for caller */
+ presult->nnewlpdead = prstate.ndead;
+
/*
- * Only incur overhead of checking if we will do an FPI if we might use
- * the information.
+ * Even if we don't prune anything, if we found a new value for the
+ * pd_prune_xid field or the page was marked full, we will update the hint
+ * bit.
*/
- if (do_prune && pagefrz)
- prune_fpi = XLogCheckBufferNeedsBackup(buffer);
-
- /* Is the whole page freezable? And is there something to freeze */
- whole_page_freezable = all_visible_except_removable &&
- presult->all_frozen;
+ do_hint = ((PageHeader) page)->pd_prune_xid != prstate.new_prune_xid ||
+ PageIsFull(page);
/*
* Freeze the page when heap_prepare_freeze_tuple indicates that at least
@@ -539,46 +537,57 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
* opportunistic freeze heuristic must be improved; however, for now, try
* to approximate it.
*/
- do_freeze = pagefrz &&
- (pagefrz->freeze_required ||
- (whole_page_freezable && presult->nfrozen > 0 && (prune_fpi || hint_bit_fpi)));
- if (do_freeze)
+ do_freeze = false;
+ if (pagefrz)
{
- heap_pre_freeze_checks(buffer, prstate.frozen, presult->nfrozen);
+ /* Is the whole page freezable? And is there something to freeze? */
+ bool whole_page_freezable = all_visible_except_removable &&
+ presult->all_frozen;
- /*
- * We can use the visibility_cutoff_xid as our cutoff for conflicts
- * when the whole page is eligible to become all-frozen in the VM once
- * we're done with it. Otherwise we generate a conservative cutoff by
- * stepping back from OldestXmin. This avoids false conflicts when
- * hot_standby_feedback is in use.
- */
- if (all_visible_except_removable && presult->all_frozen)
- frz_conflict_horizon = visibility_cutoff_xid;
- else
+ if (pagefrz->freeze_required)
+ do_freeze = true;
+ else if (whole_page_freezable && presult->nfrozen > 0)
{
- /* Avoids false conflicts when hot_standby_feedback in use */
- frz_conflict_horizon = pagefrz->cutoffs->OldestXmin;
- TransactionIdRetreat(frz_conflict_horizon);
+ /*
+ * Freezing would make the page all-frozen. In this case, we will
+ * freeze if we have already emitted an FPI or will do so anyway.
+ * Be sure only to incur the overhead of checking if we will do an
+ * FPI if we may use that information.
+ */
+ if (hint_bit_fpi ||
+ ((do_prune || do_hint) && XLogCheckBufferNeedsBackup(buffer)))
+ {
+ do_freeze = true;
+ }
}
}
- /* Any error while applying the changes is critical */
- START_CRIT_SECTION();
+ /*
+ * Validate the tuples we are considering freezing. We do this even if
+ * pruning and hint bit setting have not emitted an FPI so far because we
+ * still may emit an FPI while setting the page hint bit later. But we
+ * want to avoid doing the pre-freeze checks in a critical section.
+ */
+ if (do_freeze)
+ heap_pre_freeze_checks(buffer, prstate.frozen, presult->nfrozen);
- /* Have we found any prunable items? */
- if (do_prune)
+ if (!do_freeze && (!pagefrz || !presult->all_frozen || presult->nfrozen > 0))
{
/*
- * Apply the planned item changes, then repair page fragmentation, and
- * update the page's hint bit about whether it has free line pointers.
+ * If we will neither freeze tuples on the page nor set the page all
+ * frozen in the visibility map, the page is not all-frozen and there
+ * will be no newly frozen tuples.
*/
- heap_page_prune_execute(buffer, false,
- prstate.redirected, prstate.nredirected,
- prstate.nowdead, prstate.ndead,
- prstate.nowunused, prstate.nunused);
+ presult->all_frozen = false;
+ presult->nfrozen = 0; /* avoid miscounts in instrumentation */
+ }
+
+ /* Any error while applying the changes is critical */
+ START_CRIT_SECTION();
+ if (do_hint)
+ {
/*
* Update the page's pd_prune_xid field to either zero, or the lowest
* XID of any soon-prunable tuple.
@@ -586,12 +595,52 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
((PageHeader) page)->pd_prune_xid = prstate.new_prune_xid;
/*
- * Also clear the "page is full" flag, since there's no point in
- * repeating the prune/defrag process until something else happens to
- * the page.
+ * Clear the "page is full" flag if it is set since there's no point
+ * in repeating the prune/defrag process until something else happens
+ * to the page.
*/
PageClearFull(page);
+ /*
+ * We only needed to update pd_prune_xid and clear the page-is-full
+ * hint bit, this is a non-WAL-logged hint. If we will also freeze or
+ * prune the page, we will mark the buffer dirty below.
+ */
+ if (!do_freeze && !do_prune)
+ MarkBufferDirtyHint(buffer, true);
+ }
+
+ if (do_prune || do_freeze)
+ {
+ /* Apply the planned item changes, then repair page fragmentation. */
+ if (do_prune)
+ {
+ heap_page_prune_execute(buffer, false,
+ prstate.redirected, prstate.nredirected,
+ prstate.nowdead, prstate.ndead,
+ prstate.nowunused, prstate.nunused);
+ }
+
+ if (do_freeze)
+ {
+ /*
+ * We can use the visibility_cutoff_xid as our cutoff for
+ * conflicts when the whole page is eligible to become all-frozen
+ * in the VM once we're done with it. Otherwise we generate a
+ * conservative cutoff by stepping back from OldestXmin. This
+ * avoids false conflicts when hot_standby_feedback is in use.
+ */
+ if (all_visible_except_removable && presult->all_frozen)
+ frz_conflict_horizon = visibility_cutoff_xid;
+ else
+ {
+ /* Avoids false conflicts when hot_standby_feedback in use */
+ frz_conflict_horizon = pagefrz->cutoffs->OldestXmin;
+ TransactionIdRetreat(frz_conflict_horizon);
+ }
+ heap_freeze_prepared_tuples(buffer, prstate.frozen, presult->nfrozen);
+ }
+
MarkBufferDirty(buffer);
/*
@@ -599,72 +648,35 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
*/
if (RelationNeedsWAL(relation))
{
+ /*
+ * The snapshotConflictHorizon for the whole record should be the
+ * most conservative of all the horizons calculated for any of the
+ * possible modifications. If this record will prune tuples, any
+ * transactions on the standby older than the youngest xmax of the
+ * most recently removed tuple this record will prune will
+ * conflict. If this record will freeze tuples, any transactions
+ * on the standby with xids older than the youngest tuple this
+ * record will freeze will conflict.
+ */
+ TransactionId conflict_xid;
+
+ if (TransactionIdFollows(frz_conflict_horizon, prstate.latest_xid_removed))
+ conflict_xid = frz_conflict_horizon;
+ else
+ conflict_xid = prstate.latest_xid_removed;
+
log_heap_prune_and_freeze(relation, buffer,
- prstate.latest_xid_removed,
+ conflict_xid,
true, reason,
- NULL, 0,
+ prstate.frozen, presult->nfrozen,
prstate.redirected, prstate.nredirected,
prstate.nowdead, prstate.ndead,
prstate.nowunused, prstate.nunused);
}
}
- else
- {
- /*
- * If we didn't prune anything, but have found a new value for the
- * pd_prune_xid field, update it and mark the buffer dirty. This is
- * treated as a non-WAL-logged hint.
- *
- * Also clear the "page is full" flag if it is set, since there's no
- * point in repeating the prune/defrag process until something else
- * happens to the page.
- */
- if (((PageHeader) page)->pd_prune_xid != prstate.new_prune_xid ||
- PageIsFull(page))
- {
- ((PageHeader) page)->pd_prune_xid = prstate.new_prune_xid;
- PageClearFull(page);
- MarkBufferDirtyHint(buffer, true);
- }
- }
END_CRIT_SECTION();
- /* Record number of newly-set-LP_DEAD items for caller */
- presult->nnewlpdead = prstate.ndead;
-
- if (do_freeze)
- {
- START_CRIT_SECTION();
-
- Assert(presult->nfrozen > 0);
-
- heap_freeze_prepared_tuples(buffer, prstate.frozen, presult->nfrozen);
-
- MarkBufferDirty(buffer);
-
- /* Now WAL-log freezing if necessary */
- if (RelationNeedsWAL(relation))
- log_heap_prune_and_freeze(relation, buffer,
- frz_conflict_horizon, false, reason,
- prstate.frozen, presult->nfrozen,
- NULL, 0, /* redirected */
- NULL, 0, /* dead */
- NULL, 0); /* unused */
-
- END_CRIT_SECTION();
- }
- else if (!pagefrz || !presult->all_frozen || presult->nfrozen > 0)
- {
- /*
- * If we will neither freeze tuples on the page nor set the page all
- * frozen in the visibility map, the page is not all frozen and there
- * will be no newly frozen tuples.
- */
- presult->all_frozen = false;
- presult->nfrozen = 0; /* avoid miscounts in instrumentation */
- }
-
/*
* For callers planning to update the visibility map, the conflict horizon
* for that record must be the newest xmin on the page. However, if the
@@ -681,9 +693,10 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
* tuples on the page, if we will set the page all-frozen in the
* visibility map, we can advance relfrozenxid and relminmxid to the
* values in pagefrz->FreezePageRelfrozenXid and
- * pagefrz->FreezePageRelminMxid.
+ * pagefrz->FreezePageRelminMxid. MFIXME: which one should be pick if
+ * presult->nfrozen == 0 and presult->all_frozen = True.
*/
- if (presult->all_frozen || presult->nfrozen > 0)
+ if (presult->nfrozen > 0)
{
presult->new_relfrozenxid = pagefrz->FreezePageRelfrozenXid;
presult->new_relminmxid = pagefrz->FreezePageRelminMxid;
--
2.40.1
--caj67xgx3lukmr5f
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v9-0013-Set-hastup-in-heap_page_prune.patch"
^ permalink raw reply [nested|flat] 15+ messages in thread
* [PATCH v7 12/16] Merge prune and freeze records
@ 2024-03-26 13:37 Melanie Plageman <[email protected]>
0 siblings, 0 replies; 15+ messages in thread
From: Melanie Plageman @ 2024-03-26 13:37 UTC (permalink / raw)
When both pruning and freezing is done, this means a single, combined
WAL record is emitted for both operations. This will reduce the number
of WAL records emitted.
When there are only tuples to freeze present, we can avoid taking a full
cleanup lock when replaying the record.
---
src/backend/access/heap/heapam.c | 2 -
src/backend/access/heap/pruneheap.c | 215 +++++++++++++++-------------
2 files changed, 114 insertions(+), 103 deletions(-)
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 1c1785994b1..5d8f183085d 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -6731,8 +6731,6 @@ heap_freeze_prepared_tuples(Buffer buffer, HeapTupleFreeze *tuples, int ntuples)
htup = (HeapTupleHeader) PageGetItem(page, itemid);
heap_execute_freeze_tuple(htup, frz);
}
-
- MarkBufferDirty(buffer);
}
/*
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index 8914d4bf5c8..db8a182a197 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -249,9 +249,8 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
bool do_freeze;
bool all_visible_except_removable;
bool do_prune;
- bool whole_page_freezable;
+ bool do_hint;
bool hint_bit_fpi;
- bool prune_fpi = false;
int64 fpi_before = pgWalUsage.wal_fpi;
/*
@@ -464,10 +463,9 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
/*
* If checksums are enabled, heap_prune_satisfies_vacuum() may have caused
- * an FPI to be emitted. Then reset fpi_before for no prune case.
+ * an FPI to be emitted.
*/
hint_bit_fpi = fpi_before != pgWalUsage.wal_fpi;
- fpi_before = pgWalUsage.wal_fpi;
/*
* For vacuum, if the whole page will become frozen, we consider
@@ -517,16 +515,16 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
prstate.ndead > 0 ||
prstate.nunused > 0;
+ /* Record number of newly-set-LP_DEAD items for caller */
+ presult->nnewlpdead = prstate.ndead;
+
/*
- * Only incur overhead of checking if we will do an FPI if we might use
- * the information.
+ * Even if we don't prune anything, if we found a new value for the
+ * pd_prune_xid field or the page was marked full, we will update the hint
+ * bit.
*/
- if (do_prune && pagefrz)
- prune_fpi = XLogCheckBufferNeedsBackup(buffer);
-
- /* Is the whole page freezable? And is there something to freeze */
- whole_page_freezable = all_visible_except_removable &&
- presult->all_frozen;
+ do_hint = ((PageHeader) page)->pd_prune_xid != prstate.new_prune_xid ||
+ PageIsFull(page);
/*
* Freeze the page when heap_prepare_freeze_tuple indicates that at least
@@ -539,46 +537,57 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
* opportunistic freeze heuristic must be improved; however, for now, try
* to approximate it.
*/
- do_freeze = pagefrz &&
- (pagefrz->freeze_required ||
- (whole_page_freezable && presult->nfrozen > 0 && (prune_fpi || hint_bit_fpi)));
- if (do_freeze)
+ do_freeze = false;
+ if (pagefrz)
{
- heap_pre_freeze_checks(buffer, prstate.frozen, presult->nfrozen);
+ /* Is the whole page freezable? And is there something to freeze? */
+ bool whole_page_freezable = all_visible_except_removable &&
+ presult->all_frozen;
- /*
- * We can use the visibility_cutoff_xid as our cutoff for conflicts
- * when the whole page is eligible to become all-frozen in the VM once
- * we're done with it. Otherwise we generate a conservative cutoff by
- * stepping back from OldestXmin. This avoids false conflicts when
- * hot_standby_feedback is in use.
- */
- if (all_visible_except_removable && presult->all_frozen)
- frz_conflict_horizon = visibility_cutoff_xid;
- else
+ if (pagefrz->freeze_required)
+ do_freeze = true;
+ else if (whole_page_freezable && presult->nfrozen > 0)
{
- /* Avoids false conflicts when hot_standby_feedback in use */
- frz_conflict_horizon = pagefrz->cutoffs->OldestXmin;
- TransactionIdRetreat(frz_conflict_horizon);
+ /*
+ * Freezing would make the page all-frozen. In this case, we will
+ * freeze if we have already emitted an FPI or will do so anyway.
+ * Be sure only to incur the overhead of checking if we will do an
+ * FPI if we may use that information.
+ */
+ if (hint_bit_fpi ||
+ ((do_prune || do_hint) && XLogCheckBufferNeedsBackup(buffer)))
+ {
+ do_freeze = true;
+ }
}
}
- /* Any error while applying the changes is critical */
- START_CRIT_SECTION();
+ /*
+ * Validate the tuples we are considering freezing. We do this even if
+ * pruning and hint bit setting have not emitted an FPI so far because we
+ * still may emit an FPI while setting the page hint bit later. But we
+ * want to avoid doing the pre-freeze checks in a critical section.
+ */
+ if (do_freeze)
+ heap_pre_freeze_checks(buffer, prstate.frozen, presult->nfrozen);
- /* Have we found any prunable items? */
- if (do_prune)
+ if (!do_freeze && (!pagefrz || !presult->all_frozen || presult->nfrozen > 0))
{
/*
- * Apply the planned item changes, then repair page fragmentation, and
- * update the page's hint bit about whether it has free line pointers.
+ * If we will neither freeze tuples on the page nor set the page all
+ * frozen in the visibility map, the page is not all-frozen and there
+ * will be no newly frozen tuples.
*/
- heap_page_prune_execute(buffer, false,
- prstate.redirected, prstate.nredirected,
- prstate.nowdead, prstate.ndead,
- prstate.nowunused, prstate.nunused);
+ presult->all_frozen = false;
+ presult->nfrozen = 0; /* avoid miscounts in instrumentation */
+ }
+
+ /* Any error while applying the changes is critical */
+ START_CRIT_SECTION();
+ if (do_hint)
+ {
/*
* Update the page's pd_prune_xid field to either zero, or the lowest
* XID of any soon-prunable tuple.
@@ -586,12 +595,52 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
((PageHeader) page)->pd_prune_xid = prstate.new_prune_xid;
/*
- * Also clear the "page is full" flag, since there's no point in
- * repeating the prune/defrag process until something else happens to
- * the page.
+ * Clear the "page is full" flag if it is set since there's no point
+ * in repeating the prune/defrag process until something else happens
+ * to the page.
*/
PageClearFull(page);
+ /*
+ * We only needed to update pd_prune_xid and clear the page-is-full
+ * hint bit, this is a non-WAL-logged hint. If we will also freeze or
+ * prune the page, we will mark the buffer dirty below.
+ */
+ if (!do_freeze && !do_prune)
+ MarkBufferDirtyHint(buffer, true);
+ }
+
+ if (do_prune || do_freeze)
+ {
+ /* Apply the planned item changes, then repair page fragmentation. */
+ if (do_prune)
+ {
+ heap_page_prune_execute(buffer, false,
+ prstate.redirected, prstate.nredirected,
+ prstate.nowdead, prstate.ndead,
+ prstate.nowunused, prstate.nunused);
+ }
+
+ if (do_freeze)
+ {
+ /*
+ * We can use the visibility_cutoff_xid as our cutoff for
+ * conflicts when the whole page is eligible to become all-frozen
+ * in the VM once we're done with it. Otherwise we generate a
+ * conservative cutoff by stepping back from OldestXmin. This
+ * avoids false conflicts when hot_standby_feedback is in use.
+ */
+ if (all_visible_except_removable && presult->all_frozen)
+ frz_conflict_horizon = visibility_cutoff_xid;
+ else
+ {
+ /* Avoids false conflicts when hot_standby_feedback in use */
+ frz_conflict_horizon = pagefrz->cutoffs->OldestXmin;
+ TransactionIdRetreat(frz_conflict_horizon);
+ }
+ heap_freeze_prepared_tuples(buffer, prstate.frozen, presult->nfrozen);
+ }
+
MarkBufferDirty(buffer);
/*
@@ -599,72 +648,35 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
*/
if (RelationNeedsWAL(relation))
{
+ /*
+ * The snapshotConflictHorizon for the whole record should be the
+ * most conservative of all the horizons calculated for any of the
+ * possible modifications. If this record will prune tuples, any
+ * transactions on the standby older than the youngest xmax of the
+ * most recently removed tuple this record will prune will
+ * conflict. If this record will freeze tuples, any transactions
+ * on the standby with xids older than the youngest tuple this
+ * record will freeze will conflict.
+ */
+ TransactionId conflict_xid;
+
+ if (TransactionIdFollows(frz_conflict_horizon, prstate.latest_xid_removed))
+ conflict_xid = frz_conflict_horizon;
+ else
+ conflict_xid = prstate.latest_xid_removed;
+
log_heap_prune_and_freeze(relation, buffer,
- prstate.latest_xid_removed,
+ conflict_xid,
true, reason,
- NULL, 0,
+ prstate.frozen, presult->nfrozen,
prstate.redirected, prstate.nredirected,
prstate.nowdead, prstate.ndead,
prstate.nowunused, prstate.nunused);
}
}
- else
- {
- /*
- * If we didn't prune anything, but have found a new value for the
- * pd_prune_xid field, update it and mark the buffer dirty. This is
- * treated as a non-WAL-logged hint.
- *
- * Also clear the "page is full" flag if it is set, since there's no
- * point in repeating the prune/defrag process until something else
- * happens to the page.
- */
- if (((PageHeader) page)->pd_prune_xid != prstate.new_prune_xid ||
- PageIsFull(page))
- {
- ((PageHeader) page)->pd_prune_xid = prstate.new_prune_xid;
- PageClearFull(page);
- MarkBufferDirtyHint(buffer, true);
- }
- }
END_CRIT_SECTION();
- /* Record number of newly-set-LP_DEAD items for caller */
- presult->nnewlpdead = prstate.ndead;
-
- if (do_freeze)
- {
- START_CRIT_SECTION();
-
- Assert(presult->nfrozen > 0);
-
- heap_freeze_prepared_tuples(buffer, prstate.frozen, presult->nfrozen);
-
- MarkBufferDirty(buffer);
-
- /* Now WAL-log freezing if necessary */
- if (RelationNeedsWAL(relation))
- log_heap_prune_and_freeze(relation, buffer,
- frz_conflict_horizon, false, reason,
- prstate.frozen, presult->nfrozen,
- NULL, 0, /* redirected */
- NULL, 0, /* dead */
- NULL, 0); /* unused */
-
- END_CRIT_SECTION();
- }
- else if (!pagefrz || !presult->all_frozen || presult->nfrozen > 0)
- {
- /*
- * If we will neither freeze tuples on the page nor set the page all
- * frozen in the visibility map, the page is not all frozen and there
- * will be no newly frozen tuples.
- */
- presult->all_frozen = false;
- presult->nfrozen = 0; /* avoid miscounts in instrumentation */
- }
-
/*
* For callers planning to update the visibility map, the conflict horizon
* for that record must be the newest xmin on the page. However, if the
@@ -681,9 +693,10 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
* tuples on the page, if we will set the page all-frozen in the
* visibility map, we can advance relfrozenxid and relminmxid to the
* values in pagefrz->FreezePageRelfrozenXid and
- * pagefrz->FreezePageRelminMxid.
+ * pagefrz->FreezePageRelminMxid. MFIXME: which one should be pick if
+ * presult->nfrozen == 0 and presult->all_frozen = True.
*/
- if (presult->all_frozen || presult->nfrozen > 0)
+ if (presult->nfrozen > 0)
{
presult->new_relfrozenxid = pagefrz->FreezePageRelfrozenXid;
presult->new_relminmxid = pagefrz->FreezePageRelminMxid;
--
2.40.1
--ck6erxojvlx23byk
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v7-0013-Set-hastup-in-heap_page_prune.patch"
^ permalink raw reply [nested|flat] 15+ messages in thread
* [PATCH v7 12/16] Merge prune and freeze records
@ 2024-03-26 13:37 Melanie Plageman <[email protected]>
0 siblings, 0 replies; 15+ messages in thread
From: Melanie Plageman @ 2024-03-26 13:37 UTC (permalink / raw)
When both pruning and freezing is done, this means a single, combined
WAL record is emitted for both operations. This will reduce the number
of WAL records emitted.
When there are only tuples to freeze present, we can avoid taking a full
cleanup lock when replaying the record.
---
src/backend/access/heap/heapam.c | 2 -
src/backend/access/heap/pruneheap.c | 215 +++++++++++++++-------------
2 files changed, 114 insertions(+), 103 deletions(-)
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 1c1785994b1..5d8f183085d 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -6731,8 +6731,6 @@ heap_freeze_prepared_tuples(Buffer buffer, HeapTupleFreeze *tuples, int ntuples)
htup = (HeapTupleHeader) PageGetItem(page, itemid);
heap_execute_freeze_tuple(htup, frz);
}
-
- MarkBufferDirty(buffer);
}
/*
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index 8914d4bf5c8..db8a182a197 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -249,9 +249,8 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
bool do_freeze;
bool all_visible_except_removable;
bool do_prune;
- bool whole_page_freezable;
+ bool do_hint;
bool hint_bit_fpi;
- bool prune_fpi = false;
int64 fpi_before = pgWalUsage.wal_fpi;
/*
@@ -464,10 +463,9 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
/*
* If checksums are enabled, heap_prune_satisfies_vacuum() may have caused
- * an FPI to be emitted. Then reset fpi_before for no prune case.
+ * an FPI to be emitted.
*/
hint_bit_fpi = fpi_before != pgWalUsage.wal_fpi;
- fpi_before = pgWalUsage.wal_fpi;
/*
* For vacuum, if the whole page will become frozen, we consider
@@ -517,16 +515,16 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
prstate.ndead > 0 ||
prstate.nunused > 0;
+ /* Record number of newly-set-LP_DEAD items for caller */
+ presult->nnewlpdead = prstate.ndead;
+
/*
- * Only incur overhead of checking if we will do an FPI if we might use
- * the information.
+ * Even if we don't prune anything, if we found a new value for the
+ * pd_prune_xid field or the page was marked full, we will update the hint
+ * bit.
*/
- if (do_prune && pagefrz)
- prune_fpi = XLogCheckBufferNeedsBackup(buffer);
-
- /* Is the whole page freezable? And is there something to freeze */
- whole_page_freezable = all_visible_except_removable &&
- presult->all_frozen;
+ do_hint = ((PageHeader) page)->pd_prune_xid != prstate.new_prune_xid ||
+ PageIsFull(page);
/*
* Freeze the page when heap_prepare_freeze_tuple indicates that at least
@@ -539,46 +537,57 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
* opportunistic freeze heuristic must be improved; however, for now, try
* to approximate it.
*/
- do_freeze = pagefrz &&
- (pagefrz->freeze_required ||
- (whole_page_freezable && presult->nfrozen > 0 && (prune_fpi || hint_bit_fpi)));
- if (do_freeze)
+ do_freeze = false;
+ if (pagefrz)
{
- heap_pre_freeze_checks(buffer, prstate.frozen, presult->nfrozen);
+ /* Is the whole page freezable? And is there something to freeze? */
+ bool whole_page_freezable = all_visible_except_removable &&
+ presult->all_frozen;
- /*
- * We can use the visibility_cutoff_xid as our cutoff for conflicts
- * when the whole page is eligible to become all-frozen in the VM once
- * we're done with it. Otherwise we generate a conservative cutoff by
- * stepping back from OldestXmin. This avoids false conflicts when
- * hot_standby_feedback is in use.
- */
- if (all_visible_except_removable && presult->all_frozen)
- frz_conflict_horizon = visibility_cutoff_xid;
- else
+ if (pagefrz->freeze_required)
+ do_freeze = true;
+ else if (whole_page_freezable && presult->nfrozen > 0)
{
- /* Avoids false conflicts when hot_standby_feedback in use */
- frz_conflict_horizon = pagefrz->cutoffs->OldestXmin;
- TransactionIdRetreat(frz_conflict_horizon);
+ /*
+ * Freezing would make the page all-frozen. In this case, we will
+ * freeze if we have already emitted an FPI or will do so anyway.
+ * Be sure only to incur the overhead of checking if we will do an
+ * FPI if we may use that information.
+ */
+ if (hint_bit_fpi ||
+ ((do_prune || do_hint) && XLogCheckBufferNeedsBackup(buffer)))
+ {
+ do_freeze = true;
+ }
}
}
- /* Any error while applying the changes is critical */
- START_CRIT_SECTION();
+ /*
+ * Validate the tuples we are considering freezing. We do this even if
+ * pruning and hint bit setting have not emitted an FPI so far because we
+ * still may emit an FPI while setting the page hint bit later. But we
+ * want to avoid doing the pre-freeze checks in a critical section.
+ */
+ if (do_freeze)
+ heap_pre_freeze_checks(buffer, prstate.frozen, presult->nfrozen);
- /* Have we found any prunable items? */
- if (do_prune)
+ if (!do_freeze && (!pagefrz || !presult->all_frozen || presult->nfrozen > 0))
{
/*
- * Apply the planned item changes, then repair page fragmentation, and
- * update the page's hint bit about whether it has free line pointers.
+ * If we will neither freeze tuples on the page nor set the page all
+ * frozen in the visibility map, the page is not all-frozen and there
+ * will be no newly frozen tuples.
*/
- heap_page_prune_execute(buffer, false,
- prstate.redirected, prstate.nredirected,
- prstate.nowdead, prstate.ndead,
- prstate.nowunused, prstate.nunused);
+ presult->all_frozen = false;
+ presult->nfrozen = 0; /* avoid miscounts in instrumentation */
+ }
+
+ /* Any error while applying the changes is critical */
+ START_CRIT_SECTION();
+ if (do_hint)
+ {
/*
* Update the page's pd_prune_xid field to either zero, or the lowest
* XID of any soon-prunable tuple.
@@ -586,12 +595,52 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
((PageHeader) page)->pd_prune_xid = prstate.new_prune_xid;
/*
- * Also clear the "page is full" flag, since there's no point in
- * repeating the prune/defrag process until something else happens to
- * the page.
+ * Clear the "page is full" flag if it is set since there's no point
+ * in repeating the prune/defrag process until something else happens
+ * to the page.
*/
PageClearFull(page);
+ /*
+ * We only needed to update pd_prune_xid and clear the page-is-full
+ * hint bit, this is a non-WAL-logged hint. If we will also freeze or
+ * prune the page, we will mark the buffer dirty below.
+ */
+ if (!do_freeze && !do_prune)
+ MarkBufferDirtyHint(buffer, true);
+ }
+
+ if (do_prune || do_freeze)
+ {
+ /* Apply the planned item changes, then repair page fragmentation. */
+ if (do_prune)
+ {
+ heap_page_prune_execute(buffer, false,
+ prstate.redirected, prstate.nredirected,
+ prstate.nowdead, prstate.ndead,
+ prstate.nowunused, prstate.nunused);
+ }
+
+ if (do_freeze)
+ {
+ /*
+ * We can use the visibility_cutoff_xid as our cutoff for
+ * conflicts when the whole page is eligible to become all-frozen
+ * in the VM once we're done with it. Otherwise we generate a
+ * conservative cutoff by stepping back from OldestXmin. This
+ * avoids false conflicts when hot_standby_feedback is in use.
+ */
+ if (all_visible_except_removable && presult->all_frozen)
+ frz_conflict_horizon = visibility_cutoff_xid;
+ else
+ {
+ /* Avoids false conflicts when hot_standby_feedback in use */
+ frz_conflict_horizon = pagefrz->cutoffs->OldestXmin;
+ TransactionIdRetreat(frz_conflict_horizon);
+ }
+ heap_freeze_prepared_tuples(buffer, prstate.frozen, presult->nfrozen);
+ }
+
MarkBufferDirty(buffer);
/*
@@ -599,72 +648,35 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
*/
if (RelationNeedsWAL(relation))
{
+ /*
+ * The snapshotConflictHorizon for the whole record should be the
+ * most conservative of all the horizons calculated for any of the
+ * possible modifications. If this record will prune tuples, any
+ * transactions on the standby older than the youngest xmax of the
+ * most recently removed tuple this record will prune will
+ * conflict. If this record will freeze tuples, any transactions
+ * on the standby with xids older than the youngest tuple this
+ * record will freeze will conflict.
+ */
+ TransactionId conflict_xid;
+
+ if (TransactionIdFollows(frz_conflict_horizon, prstate.latest_xid_removed))
+ conflict_xid = frz_conflict_horizon;
+ else
+ conflict_xid = prstate.latest_xid_removed;
+
log_heap_prune_and_freeze(relation, buffer,
- prstate.latest_xid_removed,
+ conflict_xid,
true, reason,
- NULL, 0,
+ prstate.frozen, presult->nfrozen,
prstate.redirected, prstate.nredirected,
prstate.nowdead, prstate.ndead,
prstate.nowunused, prstate.nunused);
}
}
- else
- {
- /*
- * If we didn't prune anything, but have found a new value for the
- * pd_prune_xid field, update it and mark the buffer dirty. This is
- * treated as a non-WAL-logged hint.
- *
- * Also clear the "page is full" flag if it is set, since there's no
- * point in repeating the prune/defrag process until something else
- * happens to the page.
- */
- if (((PageHeader) page)->pd_prune_xid != prstate.new_prune_xid ||
- PageIsFull(page))
- {
- ((PageHeader) page)->pd_prune_xid = prstate.new_prune_xid;
- PageClearFull(page);
- MarkBufferDirtyHint(buffer, true);
- }
- }
END_CRIT_SECTION();
- /* Record number of newly-set-LP_DEAD items for caller */
- presult->nnewlpdead = prstate.ndead;
-
- if (do_freeze)
- {
- START_CRIT_SECTION();
-
- Assert(presult->nfrozen > 0);
-
- heap_freeze_prepared_tuples(buffer, prstate.frozen, presult->nfrozen);
-
- MarkBufferDirty(buffer);
-
- /* Now WAL-log freezing if necessary */
- if (RelationNeedsWAL(relation))
- log_heap_prune_and_freeze(relation, buffer,
- frz_conflict_horizon, false, reason,
- prstate.frozen, presult->nfrozen,
- NULL, 0, /* redirected */
- NULL, 0, /* dead */
- NULL, 0); /* unused */
-
- END_CRIT_SECTION();
- }
- else if (!pagefrz || !presult->all_frozen || presult->nfrozen > 0)
- {
- /*
- * If we will neither freeze tuples on the page nor set the page all
- * frozen in the visibility map, the page is not all frozen and there
- * will be no newly frozen tuples.
- */
- presult->all_frozen = false;
- presult->nfrozen = 0; /* avoid miscounts in instrumentation */
- }
-
/*
* For callers planning to update the visibility map, the conflict horizon
* for that record must be the newest xmin on the page. However, if the
@@ -681,9 +693,10 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
* tuples on the page, if we will set the page all-frozen in the
* visibility map, we can advance relfrozenxid and relminmxid to the
* values in pagefrz->FreezePageRelfrozenXid and
- * pagefrz->FreezePageRelminMxid.
+ * pagefrz->FreezePageRelminMxid. MFIXME: which one should be pick if
+ * presult->nfrozen == 0 and presult->all_frozen = True.
*/
- if (presult->all_frozen || presult->nfrozen > 0)
+ if (presult->nfrozen > 0)
{
presult->new_relfrozenxid = pagefrz->FreezePageRelfrozenXid;
presult->new_relminmxid = pagefrz->FreezePageRelminMxid;
--
2.40.1
--ck6erxojvlx23byk
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v7-0013-Set-hastup-in-heap_page_prune.patch"
^ permalink raw reply [nested|flat] 15+ messages in thread
* fix NOT VALID NOT NULL with ALTER COLUMN SET IDENTITY
@ 2025-09-03 08:30 jian he <[email protected]>
0 siblings, 1 reply; 15+ messages in thread
From: jian he @ 2025-09-03 08:30 UTC (permalink / raw)
To: pgsql-hackers
hi.
The attached patch makes the last two statements below fail.
CREATE TABLE notnull_tbl1 (a int, b int);
INSERT INTO notnull_tbl1 VALUES (NULL, 1), (300, 3);
ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; -- ok
ALTER TABLE notnull_tbl1 ALTER COLUMN a ADD GENERATED ALWAYS AS
IDENTITY; --error
ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID,
ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY; --error
but in another case,
CREATE TABLE notnull_tbl1 (a int, b int);
INSERT INTO notnull_tbl1 VALUES (NULL, 1), (300, 3);
ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID;
I am not so sure the below two statements should error out or not?
ALTER TABLE notnull_tbl1 ADD COLUMN c int GENERATED BY DEFAULT AS
IDENTITY, ADD CONSTRAINT nn NOT NULL c NOT VALID;
ALTER TABLE notnull_tbl1 ADD COLUMN d serial, ADD CONSTRAINT nn NOT
NULL c NOT VALID;
Attachments:
[text/x-patch] v1-0001-fix-NOT-VALID-NOT-NULL-CONSTRAINT-with-identity-column.patch (4.6K, ../../CACJufxGQM_+vZoYJMaRoZfNyV=L2jxosjv_0TLAScbuLJXWRfQ@mail.gmail.com/2-v1-0001-fix-NOT-VALID-NOT-NULL-CONSTRAINT-with-identity-column.patch)
download | inline diff:
From 32dc89c57e47a89d8a0719a690f70a089d738925 Mon Sep 17 00:00:00 2001
From: jian he <[email protected]>
Date: Wed, 3 Sep 2025 16:27:24 +0800
Subject: [PATCH v1 1/1] fix NOT VALID NOT NULL CONSTRAINT with identity column
fix the below problem:
CREATE TABLE notnull_tbl1 (a int, b int);
INSERT INTO notnull_tbl1 VALUES (NULL, 1), (300, 3);
ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; -- ok
ALTER TABLE notnull_tbl1 ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY; --expect error
ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID,
ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY; --expect error
---
src/backend/commands/tablecmds.c | 20 ++++++++++++++++++++
src/test/regress/expected/constraints.out | 11 +++++++++++
src/test/regress/sql/constraints.sql | 6 ++++++
3 files changed, 37 insertions(+)
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 082a3575d62..b9f1ae6788f 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -8277,6 +8277,26 @@ ATExecAddIdentity(Relation rel, const char *colName,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("column \"%s\" of relation \"%s\" must be declared NOT NULL before identity can be added",
colName, RelationGetRelationName(rel))));
+ else
+ {
+ HeapTuple contup;
+ Form_pg_constraint conForm;
+
+ contup = findNotNullConstraintAttnum(RelationGetRelid(rel),
+ attnum);
+ if (!HeapTupleIsValid(contup))
+ elog(ERROR, "cache lookup failed for not-null constraint on column \"%s\" of relation \"%s\"",
+ colName, RelationGetRelationName(rel));
+
+ conForm = (Form_pg_constraint) GETSTRUCT(contup);
+ if (!conForm->convalidated)
+ ereport(ERROR,
+ errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+ errmsg("incompatible NOT VALID constraint \"%s\" on relation \"%s\"",
+ NameStr(conForm->conname), RelationGetRelationName(rel)),
+ errhint("You might need to validate it using %s.",
+ "ALTER TABLE ... VALIDATE CONSTRAINT"));
+ }
if (attTup->attidentity)
ereport(ERROR,
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index 3590d3274f0..af448eb9b3b 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -1404,6 +1404,17 @@ ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
ERROR: cannot create primary key on column "a"
DETAIL: The constraint "nn" on column "a" of table "notnull_tbl1", marked NOT VALID, is incompatible with a primary key.
HINT: You might need to validate it using ALTER TABLE ... VALIDATE CONSTRAINT.
+-- cannot set column set identity with an invalid not-null
+ALTER TABLE notnull_tbl1 ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY;
+ERROR: incompatible NOT VALID constraint "nn" on relation "notnull_tbl1"
+HINT: You might need to validate it using ALTER TABLE ... VALIDATE CONSTRAINT.
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID, ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY;
+ERROR: incompatible NOT VALID constraint "nn" on relation "notnull_tbl1"
+HINT: You might need to validate it using ALTER TABLE ... VALIDATE CONSTRAINT.
+-- cannot set column as serial with a no inherit not-null
+ALTER TABLE notnull_tbl1 ADD COLUMN d serial, ADD CONSTRAINT nn NOT NULL d NO INHERIT;
+ERROR: cannot change NO INHERIT status of NOT NULL constraint "notnull_tbl1_d_not_null" on relation "notnull_tbl1"
+HINT: You might need to make the existing constraint inheritable using ALTER TABLE ... ALTER CONSTRAINT ... INHERIT.
-- ALTER column SET NOT NULL validates an invalid constraint (but this fails
-- because of rows with null values)
ALTER TABLE notnull_tbl1 ALTER a SET NOT NULL;
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index 1f6dc8fd69f..d31dae0b68e 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -831,6 +831,12 @@ ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a;
-- cannot add primary key on a column with an invalid not-null
ALTER TABLE notnull_tbl1 ADD PRIMARY KEY (a);
+-- cannot set column set identity with an invalid not-null
+ALTER TABLE notnull_tbl1 ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY;
+ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID, ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY;
+
+-- cannot set column as serial with a no inherit not-null
+ALTER TABLE notnull_tbl1 ADD COLUMN d serial, ADD CONSTRAINT nn NOT NULL d NO INHERIT;
-- ALTER column SET NOT NULL validates an invalid constraint (but this fails
-- because of rows with null values)
--
2.34.1
^ permalink raw reply [nested|flat] 15+ messages in thread
* Re: fix NOT VALID NOT NULL with ALTER COLUMN SET IDENTITY
@ 2025-11-03 13:33 Álvaro Herrera <[email protected]>
parent: jian he <[email protected]>
0 siblings, 1 reply; 15+ messages in thread
From: Álvaro Herrera @ 2025-11-03 13:33 UTC (permalink / raw)
To: jian he <[email protected]>; +Cc: pgsql-hackers
On 2025-Sep-03, jian he wrote:
> hi.
>
> The attached patch makes the last two statements below fail.
> CREATE TABLE notnull_tbl1 (a int, b int);
> INSERT INTO notnull_tbl1 VALUES (NULL, 1), (300, 3);
> ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID; -- ok
> ALTER TABLE notnull_tbl1 ALTER COLUMN a ADD GENERATED ALWAYS AS
> IDENTITY; --error
Yeah, I think an error here is correct.
ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID,
ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY; --error
I don't understand the difference between this test case and the
previous one ... I mean, by this point, the constraint already has a
not-null constraint, so asking to add another one does nothing.
> but in another case,
>
> CREATE TABLE notnull_tbl1 (a int, b int);
> INSERT INTO notnull_tbl1 VALUES (NULL, 1), (300, 3);
> ALTER TABLE notnull_tbl1 ADD CONSTRAINT nn NOT NULL a NOT VALID;
>
> I am not so sure the below two statements should error out or not?
> ALTER TABLE notnull_tbl1 ADD COLUMN c int GENERATED BY DEFAULT AS
> IDENTITY, ADD CONSTRAINT nn NOT NULL c NOT VALID;
> ALTER TABLE notnull_tbl1 ADD COLUMN d serial, ADD CONSTRAINT nn NOT NULL c NOT VALID;
Hmm. Here we add the column as identity or serial, which marks it as
not-null, and try to add a not-valid constraint to it on top. This
results in a valid constraint, so I think it's okay. (A new column
cannot have existing violating data.)
--
Álvaro Herrera 48°01'N 7°57'E — https://www.EnterpriseDB.com/
^ permalink raw reply [nested|flat] 15+ messages in thread
* Re: fix NOT VALID NOT NULL with ALTER COLUMN SET IDENTITY
@ 2025-11-03 14:59 Álvaro Herrera <[email protected]>
parent: Álvaro Herrera <[email protected]>
0 siblings, 0 replies; 15+ messages in thread
From: Álvaro Herrera @ 2025-11-03 14:59 UTC (permalink / raw)
To: jian he <[email protected]>; +Cc: pgsql-hackers
Pushed now to 18 and master. Thanks.
--
Álvaro Herrera Breisgau, Deutschland — https://www.EnterpriseDB.com/
"Once again, thank you and all of the developers for your hard work on
PostgreSQL. This is by far the most pleasant management experience of
any database I've worked on." (Dan Harris)
http://archives.postgresql.org/pgsql-performance/2006-04/msg00247.php
^ permalink raw reply [nested|flat] 15+ messages in thread
end of thread, other threads:[~2025-11-03 14:59 UTC | newest]
Thread overview: 15+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2024-01-07 22:55 [PATCH v2 12/17] Merge prune and freeze records Melanie Plageman <[email protected]>
2024-01-07 22:55 [PATCH v3 12/17] Merge prune and freeze records Melanie Plageman <[email protected]>
2024-01-07 22:55 [PATCH v4 13/19] Merge prune and freeze records Melanie Plageman <[email protected]>
2024-01-07 22:55 [PATCH v2 12/17] Merge prune and freeze records Melanie Plageman <[email protected]>
2024-01-07 22:55 [PATCH v3 12/17] Merge prune and freeze records Melanie Plageman <[email protected]>
2024-01-07 22:55 [PATCH v4 13/19] Merge prune and freeze records Melanie Plageman <[email protected]>
2024-01-07 22:55 [PATCH v3 12/17] Merge prune and freeze records Melanie Plageman <[email protected]>
2024-01-07 22:55 [PATCH v4 13/19] Merge prune and freeze records Melanie Plageman <[email protected]>
2024-01-07 22:55 [PATCH v2 12/17] Merge prune and freeze records Melanie Plageman <[email protected]>
2024-03-26 13:37 [PATCH v9 12/21] Merge prune and freeze records Melanie Plageman <[email protected]>
2024-03-26 13:37 [PATCH v7 12/16] Merge prune and freeze records Melanie Plageman <[email protected]>
2024-03-26 13:37 [PATCH v7 12/16] Merge prune and freeze records Melanie Plageman <[email protected]>
2025-09-03 08:30 fix NOT VALID NOT NULL with ALTER COLUMN SET IDENTITY jian he <[email protected]>
2025-11-03 13:33 ` Re: fix NOT VALID NOT NULL with ALTER COLUMN SET IDENTITY Álvaro Herrera <[email protected]>
2025-11-03 14:59 ` Re: fix NOT VALID NOT NULL with ALTER COLUMN SET IDENTITY Álvaro Herrera <[email protected]>
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