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help / color / mirror / Atom feedFrom: Melanie Plageman <[email protected]>
Subject: [PATCH v2 09/17] Separate tuple pre freeze checks and invoke earlier
Date: Sun, 7 Jan 2024 16:53:45 -0500
When combining the prune and freeze records their critical sections will
have to be combined. heap_freeze_execute_prepared() does a set of pre
freeze validations before starting its critical section. Move these
validations into a helper function, heap_pre_freeze_checks(), and invoke
it in heap_page_prune() before the pruning critical section.
Also move up the calculation of the freeze snapshot conflict horizon.
---
src/backend/access/heap/heapam.c | 58 ++++++++++++++++-------------
src/backend/access/heap/pruneheap.c | 8 +++-
src/include/access/heapam.h | 3 ++
3 files changed, 42 insertions(+), 27 deletions(-)
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 7261c4988d7..16e3f2520a4 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -6659,35 +6659,19 @@ heap_execute_freeze_tuple(HeapTupleHeader tuple, HeapTupleFreeze *frz)
}
/*
- * heap_freeze_execute_prepared
- *
- * Executes freezing of one or more heap tuples on a page on behalf of caller.
- * Caller passes an array of tuple plans from heap_prepare_freeze_tuple.
- * Caller must set 'offset' in each plan for us. Note that we destructively
- * sort caller's tuples array in-place, so caller had better be done with it.
- *
- * WAL-logs the changes so that VACUUM can advance the rel's relfrozenxid
- * later on without any risk of unsafe pg_xact lookups, even following a hard
- * crash (or when querying from a standby). We represent freezing by setting
- * infomask bits in tuple headers, but this shouldn't be thought of as a hint.
- * See section on buffer access rules in src/backend/storage/buffer/README.
- */
+* Perform xmin/xmax XID status sanity checks before calling
+* heap_freeze_execute_prepared().
+*
+* heap_prepare_freeze_tuple doesn't perform these checks directly because
+* pg_xact lookups are relatively expensive. They shouldn't be repeated
+* by successive VACUUMs that each decide against freezing the same page.
+*/
void
-heap_freeze_execute_prepared(Relation rel, Buffer buffer,
- TransactionId snapshotConflictHorizon,
- HeapTupleFreeze *tuples, int ntuples)
+heap_pre_freeze_checks(Buffer buffer,
+ HeapTupleFreeze *tuples, int ntuples)
{
Page page = BufferGetPage(buffer);
- Assert(ntuples > 0);
-
- /*
- * Perform xmin/xmax XID status sanity checks before critical section.
- *
- * heap_prepare_freeze_tuple doesn't perform these checks directly because
- * pg_xact lookups are relatively expensive. They shouldn't be repeated
- * by successive VACUUMs that each decide against freezing the same page.
- */
for (int i = 0; i < ntuples; i++)
{
HeapTupleFreeze *frz = tuples + i;
@@ -6726,6 +6710,30 @@ heap_freeze_execute_prepared(Relation rel, Buffer buffer,
xmax)));
}
}
+}
+
+/*
+ * heap_freeze_execute_prepared
+ *
+ * Executes freezing of one or more heap tuples on a page on behalf of caller.
+ * Caller passes an array of tuple plans from heap_prepare_freeze_tuple.
+ * Caller must set 'offset' in each plan for us. Note that we destructively
+ * sort caller's tuples array in-place, so caller had better be done with it.
+ *
+ * WAL-logs the changes so that VACUUM can advance the rel's relfrozenxid
+ * later on without any risk of unsafe pg_xact lookups, even following a hard
+ * crash (or when querying from a standby). We represent freezing by setting
+ * infomask bits in tuple headers, but this shouldn't be thought of as a hint.
+ * See section on buffer access rules in src/backend/storage/buffer/README.
+ */
+void
+heap_freeze_execute_prepared(Relation rel, Buffer buffer,
+ TransactionId snapshotConflictHorizon,
+ HeapTupleFreeze *tuples, int ntuples)
+{
+ Page page = BufferGetPage(buffer);
+
+ Assert(ntuples > 0);
START_CRIT_SECTION();
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index e715fc29a83..bac461940de 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -509,6 +509,12 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
(pagefrz->freeze_required ||
(whole_page_freezable && presult->nfrozen > 0 && (prune_fpi || hint_bit_fpi)));
+ if (do_freeze)
+ {
+ heap_pre_freeze_checks(buffer, frozen, presult->nfrozen);
+ frz_conflict_horizon = heap_frz_conflict_horizon(presult, pagefrz);
+ }
+
/* Any error while applying the changes is critical */
START_CRIT_SECTION();
@@ -607,8 +613,6 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
if (do_freeze)
{
- frz_conflict_horizon = heap_frz_conflict_horizon(presult, pagefrz);
-
/* Execute all freeze plans for page as a single atomic action */
heap_freeze_execute_prepared(relation, buffer,
frz_conflict_horizon,
diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h
index 69d97bb8ece..d14f36d9ce7 100644
--- a/src/include/access/heapam.h
+++ b/src/include/access/heapam.h
@@ -315,6 +315,9 @@ extern TransactionId heap_frz_conflict_horizon(PruneFreezeResult *presult,
extern bool heap_prepare_freeze_tuple(HeapTupleHeader tuple,
HeapPageFreeze *pagefrz,
HeapTupleFreeze *frz, bool *totally_frozen);
+
+extern void heap_pre_freeze_checks(Buffer buffer,
+ HeapTupleFreeze *tuples, int ntuples);
extern void heap_freeze_execute_prepared(Relation rel, Buffer buffer,
TransactionId snapshotConflictHorizon,
HeapTupleFreeze *tuples, int ntuples);
--
2.40.1
--rdqtp5puvxqotfdw
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v2-0010-Inline-heap_freeze_execute_prepared.patch"
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