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authorHeikki Linnakangas2024-04-03 16:32:21 +0000
committerHeikki Linnakangas2024-04-03 16:32:21 +0000
commit26d138f64474394cf1e573384e8f38efa637b674 (patch)
treed00fc7b7f0e260765a6d61a4054a2a1d5d5532cc
parentbe2f0731006300876b008fd78a265471984cbcd9 (diff)
Refactor how heap_prune_chain() updates prunable_xid
In preparation of freezing and counting tuples which are not candidates for pruning, split heap_prune_record_unchanged() into multiple functions, depending the kind of line pointer. That's not too interesting right now, but makes the next commit smaller. Recording the lowest soon-to-be prunable xid is one of the actions we take for unchanged LP_NORMAL item pointers but not for others, so move that to the new heap_prune_record_unchanged_lp_normal() function. The next commit will add more actions to these functions. Author: Melanie Plageman <[email protected]> Discussion: https://www.postgresql.org/message-id/20240330055710.kqg6ii2cdojsxgje@liskov
-rw-r--r--src/backend/access/heap/pruneheap.c125
1 files changed, 92 insertions, 33 deletions
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index ef563e19aa5..1b5bf990d21 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -78,7 +78,11 @@ static void heap_prune_record_redirect(PruneState *prstate,
static void heap_prune_record_dead(PruneState *prstate, OffsetNumber offnum, bool was_normal);
static void heap_prune_record_dead_or_unused(PruneState *prstate, OffsetNumber offnum, bool was_normal);
static void heap_prune_record_unused(PruneState *prstate, OffsetNumber offnum, bool was_normal);
-static void heap_prune_record_unchanged(PruneState *prstate, OffsetNumber offnum);
+
+static void heap_prune_record_unchanged_lp_unused(Page page, PruneState *prstate, OffsetNumber offnum);
+static void heap_prune_record_unchanged_lp_normal(Page page, int8 *htsv, PruneState *prstate, OffsetNumber offnum);
+static void heap_prune_record_unchanged_lp_dead(Page page, PruneState *prstate, OffsetNumber offnum);
+static void heap_prune_record_unchanged_lp_redirect(PruneState *prstate, OffsetNumber offnum);
static void page_verify_redirects(Page page);
@@ -311,7 +315,7 @@ heap_page_prune(Relation relation, Buffer buffer,
/* Nothing to do if slot doesn't contain a tuple */
if (!ItemIdIsUsed(itemid))
{
- heap_prune_record_unchanged(&prstate, offnum);
+ heap_prune_record_unchanged_lp_unused(page, &prstate, offnum);
continue;
}
@@ -324,7 +328,7 @@ heap_page_prune(Relation relation, Buffer buffer,
if (unlikely(prstate.mark_unused_now))
heap_prune_record_unused(&prstate, offnum, false);
else
- heap_prune_record_unchanged(&prstate, offnum);
+ heap_prune_record_unchanged_lp_dead(page, &prstate, offnum);
continue;
}
@@ -434,7 +438,7 @@ heap_page_prune(Relation relation, Buffer buffer,
}
}
else
- heap_prune_record_unchanged(&prstate, offnum);
+ heap_prune_record_unchanged_lp_normal(page, presult->htsv, &prstate, offnum);
}
/* We should now have processed every tuple exactly once */
@@ -652,9 +656,6 @@ heap_prune_chain(Page page, BlockNumber blockno, OffsetNumber maxoff,
*/
chainitems[nchain++] = offnum;
- /*
- * Check tuple's visibility status.
- */
switch (htsv_get_valid_status(htsv[offnum]))
{
case HEAPTUPLE_DEAD:
@@ -670,9 +671,6 @@ heap_prune_chain(Page page, BlockNumber blockno, OffsetNumber maxoff,
case HEAPTUPLE_RECENTLY_DEAD:
/*
- * This tuple may soon become DEAD. Update the hint field so
- * that the page is reconsidered for pruning in future.
- *
* We don't need to advance the conflict horizon for
* RECENTLY_DEAD tuples, even if we are removing them. This
* is because we only remove RECENTLY_DEAD tuples if they
@@ -681,8 +679,6 @@ heap_prune_chain(Page page, BlockNumber blockno, OffsetNumber maxoff,
* tuple by virtue of being later in the chain. We will have
* advanced the conflict horizon for the DEAD tuple.
*/
- heap_prune_record_prunable(prstate,
- HeapTupleHeaderGetUpdateXid(htup));
/*
* Advance past RECENTLY_DEAD tuples just in case there's a
@@ -693,24 +689,8 @@ heap_prune_chain(Page page, BlockNumber blockno, OffsetNumber maxoff,
break;
case HEAPTUPLE_DELETE_IN_PROGRESS:
-
- /*
- * This tuple may soon become DEAD. Update the hint field so
- * that the page is reconsidered for pruning in future.
- */
- heap_prune_record_prunable(prstate,
- HeapTupleHeaderGetUpdateXid(htup));
- goto process_chain;
-
case HEAPTUPLE_LIVE:
case HEAPTUPLE_INSERT_IN_PROGRESS:
-
- /*
- * If we wanted to optimize for aborts, we might consider
- * marking the page prunable when we see INSERT_IN_PROGRESS.
- * But we don't. See related decisions about when to mark the
- * page prunable in heapam.c.
- */
goto process_chain;
default:
@@ -757,8 +737,15 @@ process_chain:
* No DEAD tuple was found, so the chain is entirely composed of
* normal, unchanged tuples. Leave it alone.
*/
- for (int i = 0; i < nchain; i++)
- heap_prune_record_unchanged(prstate, chainitems[i]);
+ int i = 0;
+
+ if (ItemIdIsRedirected(rootlp))
+ {
+ heap_prune_record_unchanged_lp_redirect(prstate, rootoffnum);
+ i++;
+ }
+ for (; i < nchain; i++)
+ heap_prune_record_unchanged_lp_normal(page, htsv, prstate, chainitems[i]);
}
else if (ndeadchain == nchain)
{
@@ -784,7 +771,7 @@ process_chain:
/* the rest of tuples in the chain are normal, unchanged tuples */
for (int i = ndeadchain; i < nchain; i++)
- heap_prune_record_unchanged(prstate, chainitems[i]);
+ heap_prune_record_unchanged_lp_normal(page, htsv, prstate, chainitems[i]);
}
}
@@ -894,9 +881,81 @@ heap_prune_record_unused(PruneState *prstate, OffsetNumber offnum, bool was_norm
prstate->ndeleted++;
}
-/* Record a line pointer that is left unchanged */
+/*
+ * Record an unused line pointer that is left unchanged.
+ */
+static void
+heap_prune_record_unchanged_lp_unused(Page page, PruneState *prstate, OffsetNumber offnum)
+{
+ Assert(!prstate->processed[offnum]);
+ prstate->processed[offnum] = true;
+}
+
+/*
+ * Record LP_NORMAL line pointer that is left unchanged.
+ */
+static void
+heap_prune_record_unchanged_lp_normal(Page page, int8 *htsv, PruneState *prstate, OffsetNumber offnum)
+{
+ HeapTupleHeader htup;
+
+ Assert(!prstate->processed[offnum]);
+ prstate->processed[offnum] = true;
+
+ switch (htsv[offnum])
+ {
+ case HEAPTUPLE_LIVE:
+ case HEAPTUPLE_INSERT_IN_PROGRESS:
+
+ /*
+ * If we wanted to optimize for aborts, we might consider marking
+ * the page prunable when we see INSERT_IN_PROGRESS. But we
+ * don't. See related decisions about when to mark the page
+ * prunable in heapam.c.
+ */
+ break;
+
+ case HEAPTUPLE_RECENTLY_DEAD:
+ case HEAPTUPLE_DELETE_IN_PROGRESS:
+
+ htup = (HeapTupleHeader) PageGetItem(page, PageGetItemId(page, offnum));
+
+ /*
+ * This tuple may soon become DEAD. Update the hint field so that
+ * the page is reconsidered for pruning in future.
+ */
+ heap_prune_record_prunable(prstate,
+ HeapTupleHeaderGetUpdateXid(htup));
+ break;
+
+
+ default:
+
+ /*
+ * DEAD tuples should've been passed to heap_prune_record_dead()
+ * or heap_prune_record_unused() instead.
+ */
+ elog(ERROR, "unexpected HeapTupleSatisfiesVacuum result %d", htsv[offnum]);
+ break;
+ }
+}
+
+
+/*
+ * Record line pointer that was already LP_DEAD and is left unchanged.
+ */
+static void
+heap_prune_record_unchanged_lp_dead(Page page, PruneState *prstate, OffsetNumber offnum)
+{
+ Assert(!prstate->processed[offnum]);
+ prstate->processed[offnum] = true;
+}
+
+/*
+ * Record LP_REDIRECT that is left unchanged.
+ */
static void
-heap_prune_record_unchanged(PruneState *prstate, OffsetNumber offnum)
+heap_prune_record_unchanged_lp_redirect(PruneState *prstate, OffsetNumber offnum)
{
Assert(!prstate->processed[offnum]);
prstate->processed[offnum] = true;