Rebased against 40d964ec997f64227bc0ff5e058dc4a5770a70a9
I moved some unrelated patches to a separate thread ("vacuum verbose detail
logs are unclear")
>From 33c7166e3c8f056a8eb6295ec92fed8c85eda7d6 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <[email protected]>
Date: Mon, 23 Dec 2019 14:38:01 -0600
Subject: [PATCH v9 1/3] dedup2: skip_blocks
---
src/backend/access/heap/vacuumlazy.c | 187 ++++++++++++++++-------------------
1 file changed, 84 insertions(+), 103 deletions(-)
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index b331f4c..9849685 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -660,6 +660,88 @@ vacuum_log_cleanup_info(Relation rel, LVRelStats *vacrelstats)
}
/*
+ * Return whether skipping blocks or not.
+ * Except when aggressive is set, we want to skip pages that are
+ * all-visible according to the visibility map, but only when we can skip
+ * at least SKIP_PAGES_THRESHOLD consecutive pages. Since we're reading
+ * sequentially, the OS should be doing readahead for us, so there's no
+ * gain in skipping a page now and then; that's likely to disable
+ * readahead and so be counterproductive. Also, skipping even a single
+ * page means that we can't update relfrozenxid, so we only want to do it
+ * if we can skip a goodly number of pages.
+ *
+ * When aggressive is set, we can't skip pages just because they are
+ * all-visible, but we can still skip pages that are all-frozen, since
+ * such pages do not need freezing and do not affect the value that we can
+ * safely set for relfrozenxid or relminmxid.
+ *
+ * Before entering the main loop, establish the invariant that
+ * next_unskippable_block is the next block number >= blkno that we can't
+ * skip based on the visibility map, either all-visible for a regular scan
+ * or all-frozen for an aggressive scan. We set it to nblocks if there's
+ * no such block. We also set up the skipping_blocks flag correctly at
+ * this stage.
+ *
+ * Note: The value returned by visibilitymap_get_status could be slightly
+ * out-of-date, since we make this test before reading the corresponding
+ * heap page or locking the buffer. This is OK. If we mistakenly think
+ * that the page is all-visible or all-frozen when in fact the flag's just
+ * been cleared, we might fail to vacuum the page. It's easy to see that
+ * skipping a page when aggressive is not set is not a very big deal; we
+ * might leave some dead tuples lying around, but the next vacuum will
+ * find them. But even when aggressive *is* set, it's still OK if we miss
+ * a page whose all-frozen marking has just been cleared. Any new XIDs
+ * just added to that page are necessarily newer than the GlobalXmin we
+ * computed, so they'll have no effect on the value to which we can safely
+ * set relfrozenxid. A similar argument applies for MXIDs and relminmxid.
+ *
+ * We will scan the table's last page, at least to the extent of
+ * determining whether it has tuples or not, even if it should be skipped
+ * according to the above rules; except when we've already determined that
+ * it's not worth trying to truncate the table. This avoids having
+ * lazy_truncate_heap() take access-exclusive lock on the table to attempt
+ * a truncation that just fails immediately because there are tuples in
+ * the last page. This is worth avoiding mainly because such a lock must
+ * be replayed on any hot standby, where it can be disruptive.
+ */
+static bool
+skip_blocks(Relation onerel, VacuumParams *params, BlockNumber *next_unskippable_block, BlockNumber nblocks, Buffer *vmbuffer, bool aggressive)
+{
+ if ((params->options & VACOPT_DISABLE_PAGE_SKIPPING) == 0)
+ {
+ while (*next_unskippable_block < nblocks)
+ {
+ uint8 vmstatus;
+
+ vmstatus = visibilitymap_get_status(onerel, *next_unskippable_block,
+ vmbuffer);
+ if (aggressive)
+ {
+ if ((vmstatus & VISIBILITYMAP_ALL_FROZEN) == 0)
+ break;
+ }
+ else
+ {
+ if ((vmstatus & VISIBILITYMAP_ALL_VISIBLE) == 0)
+ break;
+ }
+ vacuum_delay_point();
+ ++*next_unskippable_block;
+ }
+ }
+
+
+ /*
+ * We know we can't skip the current block. But set up
+ * skipping_blocks to do the right thing at the following blocks.
+ */
+ if (*next_unskippable_block >= SKIP_PAGES_THRESHOLD)
+ return true;
+ else
+ return false;
+}
+
+/*
* lazy_scan_heap() -- scan an open heap relation
*
* This routine prunes each page in the heap, which will among other
@@ -794,78 +876,8 @@ lazy_scan_heap(Relation onerel, VacuumParams *params, LVRelStats *vacrelstats,
initprog_val[2] = dead_tuples->max_tuples;
pgstat_progress_update_multi_param(3, initprog_index, initprog_val);
- /*
- * Except when aggressive is set, we want to skip pages that are
- * all-visible according to the visibility map, but only when we can skip
- * at least SKIP_PAGES_THRESHOLD consecutive pages. Since we're reading
- * sequentially, the OS should be doing readahead for us, so there's no
- * gain in skipping a page now and then; that's likely to disable
- * readahead and so be counterproductive. Also, skipping even a single
- * page means that we can't update relfrozenxid, so we only want to do it
- * if we can skip a goodly number of pages.
- *
- * When aggressive is set, we can't skip pages just because they are
- * all-visible, but we can still skip pages that are all-frozen, since
- * such pages do not need freezing and do not affect the value that we can
- * safely set for relfrozenxid or relminmxid.
- *
- * Before entering the main loop, establish the invariant that
- * next_unskippable_block is the next block number >= blkno that we can't
- * skip based on the visibility map, either all-visible for a regular scan
- * or all-frozen for an aggressive scan. We set it to nblocks if there's
- * no such block. We also set up the skipping_blocks flag correctly at
- * this stage.
- *
- * Note: The value returned by visibilitymap_get_status could be slightly
- * out-of-date, since we make this test before reading the corresponding
- * heap page or locking the buffer. This is OK. If we mistakenly think
- * that the page is all-visible or all-frozen when in fact the flag's just
- * been cleared, we might fail to vacuum the page. It's easy to see that
- * skipping a page when aggressive is not set is not a very big deal; we
- * might leave some dead tuples lying around, but the next vacuum will
- * find them. But even when aggressive *is* set, it's still OK if we miss
- * a page whose all-frozen marking has just been cleared. Any new XIDs
- * just added to that page are necessarily newer than the GlobalXmin we
- * computed, so they'll have no effect on the value to which we can safely
- * set relfrozenxid. A similar argument applies for MXIDs and relminmxid.
- *
- * We will scan the table's last page, at least to the extent of
- * determining whether it has tuples or not, even if it should be skipped
- * according to the above rules; except when we've already determined that
- * it's not worth trying to truncate the table. This avoids having
- * lazy_truncate_heap() take access-exclusive lock on the table to attempt
- * a truncation that just fails immediately because there are tuples in
- * the last page. This is worth avoiding mainly because such a lock must
- * be replayed on any hot standby, where it can be disruptive.
- */
next_unskippable_block = 0;
- if ((params->options & VACOPT_DISABLE_PAGE_SKIPPING) == 0)
- {
- while (next_unskippable_block < nblocks)
- {
- uint8 vmstatus;
-
- vmstatus = visibilitymap_get_status(onerel, next_unskippable_block,
- &vmbuffer);
- if (aggressive)
- {
- if ((vmstatus & VISIBILITYMAP_ALL_FROZEN) == 0)
- break;
- }
- else
- {
- if ((vmstatus & VISIBILITYMAP_ALL_VISIBLE) == 0)
- break;
- }
- vacuum_delay_point();
- next_unskippable_block++;
- }
- }
-
- if (next_unskippable_block >= SKIP_PAGES_THRESHOLD)
- skipping_blocks = true;
- else
- skipping_blocks = false;
+ skipping_blocks = skip_blocks(onerel, params, &next_unskippable_block, nblocks, &vmbuffer, aggressive);
for (blkno = 0; blkno < nblocks; blkno++)
{
@@ -894,38 +906,7 @@ lazy_scan_heap(Relation onerel, VacuumParams *params, LVRelStats *vacrelstats,
{
/* Time to advance next_unskippable_block */
next_unskippable_block++;
- if ((params->options & VACOPT_DISABLE_PAGE_SKIPPING) == 0)
- {
- while (next_unskippable_block < nblocks)
- {
- uint8 vmskipflags;
-
- vmskipflags = visibilitymap_get_status(onerel,
- next_unskippable_block,
- &vmbuffer);
- if (aggressive)
- {
- if ((vmskipflags & VISIBILITYMAP_ALL_FROZEN) == 0)
- break;
- }
- else
- {
- if ((vmskipflags & VISIBILITYMAP_ALL_VISIBLE) == 0)
- break;
- }
- vacuum_delay_point();
- next_unskippable_block++;
- }
- }
-
- /*
- * We know we can't skip the current block. But set up
- * skipping_blocks to do the right thing at the following blocks.
- */
- if (next_unskippable_block - blkno > SKIP_PAGES_THRESHOLD)
- skipping_blocks = true;
- else
- skipping_blocks = false;
+ skipping_blocks = skip_blocks(onerel, params, &next_unskippable_block, nblocks, &vmbuffer, aggressive);
/*
* Normally, the fact that we can't skip this block must mean that
--
2.7.4
>From 623c725c8add0670b28cdbfceca1824ba5b0647c Mon Sep 17 00:00:00 2001
From: Justin Pryzby <[email protected]>
Date: Thu, 12 Dec 2019 20:54:37 -0600
Subject: [PATCH v9 2/3] vacuum errcontext to show block being processed
As requested here.
https://www.postgresql.org/message-id/20190807235154.erbmr4o4bo6vgnjv%40alap3.anarazel.de
---
src/backend/access/heap/vacuumlazy.c | 37 ++++++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index 9849685..c96abdf 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -289,6 +289,12 @@ typedef struct LVRelStats
bool lock_waiter_detected;
} LVRelStats;
+typedef struct
+{
+ char *relname;
+ char *relnamespace;
+ BlockNumber blkno;
+} vacuum_error_callback_arg;
/* A few variables that don't seem worth passing around as parameters */
static int elevel = -1;
@@ -358,6 +364,7 @@ static void end_parallel_vacuum(Relation *Irel, IndexBulkDeleteResult **stats,
LVParallelState *lps, int nindexes);
static LVSharedIndStats *get_indstats(LVShared *lvshared, int n);
static bool skip_parallel_vacuum_index(Relation indrel, LVShared *lvshared);
+static void vacuum_error_callback(void *arg);
/*
@@ -803,6 +810,8 @@ lazy_scan_heap(Relation onerel, VacuumParams *params, LVRelStats *vacrelstats,
PROGRESS_VACUUM_MAX_DEAD_TUPLES
};
int64 initprog_val[3];
+ ErrorContextCallback errcallback;
+ vacuum_error_callback_arg errcbarg;
pg_rusage_init(&ru0);
@@ -879,6 +888,15 @@ lazy_scan_heap(Relation onerel, VacuumParams *params, LVRelStats *vacrelstats,
next_unskippable_block = 0;
skipping_blocks = skip_blocks(onerel, params, &next_unskippable_block, nblocks, &vmbuffer, aggressive);
+ /* Setup error traceback support for ereport() */
+ errcbarg.relnamespace = get_namespace_name(RelationGetNamespace(onerel));
+ errcbarg.relname = relname;
+ errcbarg.blkno = InvalidBlockNumber; /* Not known yet */
+ errcallback.callback = vacuum_error_callback;
+ errcallback.arg = (void *) &errcbarg;
+ errcallback.previous = error_context_stack;
+ error_context_stack = &errcallback;
+
for (blkno = 0; blkno < nblocks; blkno++)
{
Buffer buf;
@@ -900,6 +918,8 @@ lazy_scan_heap(Relation onerel, VacuumParams *params, LVRelStats *vacrelstats,
#define FORCE_CHECK_PAGE() \
(blkno == nblocks - 1 && should_attempt_truncation(params, vacrelstats))
+ errcbarg.blkno = blkno;
+
pgstat_progress_update_param(PROGRESS_VACUUM_HEAP_BLKS_SCANNED, blkno);
if (blkno == next_unskippable_block)
@@ -966,8 +986,11 @@ lazy_scan_heap(Relation onerel, VacuumParams *params, LVRelStats *vacrelstats,
}
/* Work on all the indexes, then the heap */
+ /* Don't use the errcontext handler outside this function */
+ error_context_stack = errcallback.previous;
lazy_vacuum_all_indexes(onerel, Irel, indstats,
vacrelstats, lps, nindexes);
+ error_context_stack = &errcallback;
/* Remove tuples from heap */
lazy_vacuum_heap(onerel, vacrelstats);
@@ -1575,6 +1598,9 @@ lazy_scan_heap(Relation onerel, VacuumParams *params, LVRelStats *vacrelstats,
RecordPageWithFreeSpace(onerel, blkno, freespace);
}
+ /* Pop the error context stack */
+ error_context_stack = errcallback.previous;
+
/* report that everything is scanned and vacuumed */
pgstat_progress_update_param(PROGRESS_VACUUM_HEAP_BLKS_SCANNED, blkno);
@@ -3353,3 +3379,14 @@ parallel_vacuum_main(dsm_segment *seg, shm_toc *toc)
table_close(onerel, ShareUpdateExclusiveLock);
pfree(stats);
}
+
+/*
+ * Error context callback for errors occurring during vacuum.
+ */
+static void
+vacuum_error_callback(void *arg)
+{
+ vacuum_error_callback_arg *cbarg = arg;
+ errcontext("while scanning block %u of relation \"%s.%s\"",
+ cbarg->blkno, cbarg->relnamespace, cbarg->relname);
+}
--
2.7.4
>From 27a0c085d8d965252ebb8eb2e47362f27fa4203e Mon Sep 17 00:00:00 2001
From: Justin Pryzby <[email protected]>
Date: Thu, 12 Dec 2019 20:34:03 -0600
Subject: [PATCH v9 3/3] add errcontext callback in lazy_vacuum_heap, too
---
src/backend/access/heap/vacuumlazy.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index c96abdf..f380437 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -1639,6 +1639,7 @@ lazy_scan_heap(Relation onerel, VacuumParams *params, LVRelStats *vacrelstats,
/* Remove tuples from heap */
lazy_vacuum_heap(onerel, vacrelstats);
+ error_context_stack = errcallback.previous;
}
/*
@@ -1777,10 +1778,22 @@ lazy_vacuum_heap(Relation onerel, LVRelStats *vacrelstats)
PGRUsage ru0;
Buffer vmbuffer = InvalidBuffer;
+ ErrorContextCallback errcallback;
+ vacuum_error_callback_arg errcbarg;
+
/* Report that we are now vacuuming the heap */
pgstat_progress_update_param(PROGRESS_VACUUM_PHASE,
PROGRESS_VACUUM_PHASE_VACUUM_HEAP);
+ /* Setup error traceback support for ereport() */
+ errcbarg.relnamespace = get_namespace_name(RelationGetNamespace(onerel));
+ errcbarg.relname = RelationGetRelationName(onerel);
+ errcbarg.blkno = InvalidBlockNumber; /* Not known yet */
+ errcallback.callback = vacuum_error_callback;
+ errcallback.arg = (void *) &errcbarg;
+ errcallback.previous = error_context_stack;
+ error_context_stack = &errcallback;
+
pg_rusage_init(&ru0);
npages = 0;
@@ -1795,6 +1808,7 @@ lazy_vacuum_heap(Relation onerel, LVRelStats *vacrelstats)
vacuum_delay_point();
tblk = ItemPointerGetBlockNumber(&vacrelstats->dead_tuples->itemptrs[tupindex]);
+ errcbarg.blkno = tblk;
buf = ReadBufferExtended(onerel, MAIN_FORKNUM, tblk, RBM_NORMAL,
vac_strategy);
if (!ConditionalLockBufferForCleanup(buf))
--
2.7.4
