public inbox for [email protected]
help / color / mirror / Atom feedFrom: Melanie Plageman <[email protected]>
To: Kirill Reshke <[email protected]>
Cc: Andres Freund <[email protected]>
Cc: Robert Haas <[email protected]>
Cc: Andrey Borodin <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Cc: Heikki Linnakangas <[email protected]>
Subject: Re: eliminate xl_heap_visible to reduce WAL (and eventually set VM on-access)
Date: Tue, 4 Nov 2025 11:48:15 -0500
Message-ID: <CAAKRu_YS+Ocm=OzMaZnG4egFiE9v4VYfZ25DXd6jbwegqmGYbQ@mail.gmail.com> (raw)
In-Reply-To: <CALdSSPhiCwJwWwgJP1NmqRmnp9RS2tGOBY0gQrfLCbB+OS5_KQ@mail.gmail.com>
References: <CAAKRu_YX0NP_yhXvPnvDRjVxxprsRBM-_MZzAJskfMydMQ=ETA@mail.gmail.com>
<CA+TgmoZef8XqRujP1NN=wJdV4SxOtu7rxRozsyAtaEvuVMZhEw@mail.gmail.com>
<CAAKRu_YxD3UC3BXxS55jPjBC_yj_vn3FVoLvBMwQuHXGDXacGg@mail.gmail.com>
<CA+TgmobYY2URHKBMh1NHo1zF3Z28TiS_+0aSyRYyBfvauCPZzA@mail.gmail.com>
<CAAKRu_YOJ3VTKo4Z9vB2hGeTnwVWsL39gXH09vyBUQ7bGtDnKA@mail.gmail.com>
<yn4zp35kkdsjx6wf47zcfmxgexxt4h2og47pvnw2x5ifyrs3qc@7uw6jyyxuyf7>
<CAAKRu_ZiuR+YcUc7=TrgANbRakpzCu8X9zqR=Tf0fE6uDbfP1g@mail.gmail.com>
<CA+TgmoYgCs=SEsohP6Z6R3KKsGaqFqvqxH8vQ_-nY4t+7rK8jg@mail.gmail.com>
<CAAKRu_ZP-3=SaZykpwDBMJOdUKyW3Wm5JZfPFRR3L5Ac8ouq4w@mail.gmail.com>
<CAAKRu_bgkOQqu3K5n4YLRsNBZqJ9Rjg80ROqgKSr2UGz4b5hUg@mail.gmail.com>
<2wk7jo4m4qwh5sn33pfgerdjfujebbccsmmlownybddbh6nawl@mdyyqpqzxjek>
<CAAKRu_YR-COJ9aGnMUQqt5yoWmUBjikqrd4jGNZYouHaXpis9g@mail.gmail.com>
<CALdSSPhiCwJwWwgJP1NmqRmnp9RS2tGOBY0gQrfLCbB+OS5_KQ@mail.gmail.com>
Thanks for the review!
On Wed, Oct 29, 2025 at 7:03 AM Kirill Reshke <[email protected]> wrote:
>
> get_conflict_xid function logic is bit strange for me, it assigns
> conflict_xid to some value, but in the very end we have
>
> > + /*
> >+ * We can omit the snapshot conflict horizon if we are not pruning or
> >+ * freezing any tuples and are setting an already all-visible page
> >+ * all-frozen in the VM. In this case, all of the tuples on the page must
> >+ * already be visible to all MVCC snapshots on the standby.
> >+ */
> >+ if (!do_prune && !do_freeze &&
> >+ do_set_vm && blk_already_av && set_blk_all_frozen)
> > + conflict_xid = InvalidTransactionId;
>
> I feel like we should move this check to the beginning of the
> function, and just return InvalidTransactionId in that if cond.
You're right. I've changed it as you suggest in attached v19.
> > + if (old_vmbits == new_vmbits)
> > + {
> > + LockBuffer(vmbuffer, BUFFER_LOCK_UNLOCK);
> > + /* Unset so we don't emit WAL since no change occurred */
> > + do_set_vm = false;
> > + }
>
> and then
>
> > END_CRIT_SECTION();
> > + if (do_set_vm)
> > + LockBuffer(vmbuffer, BUFFER_LOCK_UNLOCK);
> > +
>
> So, in the heap_page_prune_and_freeze function we release buffer lock
> both inside and outside the crit section. As I understand, this is
> actually safe. I also looked in other xlog coding practices for other
> access methods (GiST, GIN, ....), and I can see that some of them
> release buffers before leaving crit sections and some of them after.
> But I still suggest to be in sync with 'Write-Ahead Log Coding'
> section of
> src/backend/access/transam/README, which says:
>
> 6. END_CRIT_SECTION()
>
> 7. Unlock and unpin the buffer(s).
>
> Let's be consistent in this at least in this single function context.
I see what you are saying. However, I don't see a good way to
determine whether or not we need to unlock the VM without introducing
another local variable in the outermost scope -- like "unlock_vm".
This function already has a lot of local variables, so I'm loath to do
that. And we want do_set_vm to reflect whether or not we actually set
it in case it gets used in the future.
This function doesn't lock or unlock the heap buffer so it doesn't
seem as urgent to me to follow the letter of the law in this case.
Attached patch doesn't have this change, but this is what it would look like:
/* Lock vmbuffer before entering a critical section */
+ unlock_vm = do_set_vm;
if (do_set_vm)
LockBuffer(vmbuffer, BUFFER_LOCK_EXCLUSIVE);
@@ -1112,12 +1114,9 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
old_vmbits = visibilitymap_set(blockno,
vmbuffer, new_vmbits,
params->relation->rd_locator);
- if (old_vmbits == new_vmbits)
- {
- LockBuffer(vmbuffer, BUFFER_LOCK_UNLOCK);
- /* Unset so we don't emit WAL since no change occurred */
- do_set_vm = false;
- }
+
+ /* Unset so we don't emit WAL since no change occurred */
+ do_set_vm = old_vmbits != new_vmbits;
}
/*
@@ -1145,7 +1144,7 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
END_CRIT_SECTION();
- if (do_set_vm)
+ if (unlock_vm)
LockBuffer(vmbuffer, BUFFER_LOCK_UNLOCK);
> In 0010:
>
> I'm not terribly convenient that adding SO_ALLOW_VM_SET to TAM
> ScanOptions is the right thing to do. Looks like VM bits are something
> that make sense for HEAP AM for not for any TAM. So, don't we break
> some layer of abstraction here? Would it be better for HEAP AM to set
> some flags in heap_beginscan?
I don't see another good way of doing it.
The information about whether or not the relation is modified in the
query is gathered during planning and saved in the plan. We need to
get that information to the scan descriptor, which is all we have when
we call heap_page_prune_opt() during the scan. The scan descriptor is
created by the table AM implementations of scan_begin(). The table AM
callbacks don't pass down the plan -- which makes sense; the scan
shouldn't know about the plan. They do pass down flags, so I thought
it made the most sense to add a flag. Note that I was able to avoid
modifying the actual table and index AM callbacks (scan_begin() and
ambeginscan()). I only made new wrappers that took "modifies_rel".
Now, it is true that referring to the VM is somewhat of a layering
violation. Though, other table AMs may use the information about if
the query modifies the relation -- which is really what this flag
represents. The ScanOptions are usually either a type or a call to
action. Which is why I felt a bit uncomfortable calling it something
like SO_MODIFIES_REL -- which is less of an option and more a piece of
information. And it makes it sound like the scan modifies the rel,
which is not the case. I wonder if there is another solution. Or maybe
we call it SO_QUERY_MODIFIES_REL?
- Melanie
Attachments:
[text/x-patch] v19-0001-Refactor-heap_page_prune_and_freeze-parameters-i.patch (12.8K, 2-v19-0001-Refactor-heap_page_prune_and_freeze-parameters-i.patch)
download | inline diff:
From 338f6e31bf029527a3898fee1fbe587e24de9f5f Mon Sep 17 00:00:00 2001
From: Melanie Plageman <[email protected]>
Date: Tue, 14 Oct 2025 11:10:25 -0400
Subject: [PATCH v19 01/12] Refactor heap_page_prune_and_freeze() parameters
into a struct
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
heap_page_prune_and_freeze() had accumulated an unwieldy number of input
parameters, and upcoming work to handle VM updates in this function will
add even more.
Introduce a new PruneFreezeParams struct to group the function’s input
parameters, improving readability and maintainability.
Discussion: https://postgr.es/m/yn4zp35kkdsjx6wf47zcfmxgexxt4h2og47pvnw2x5ifyrs3qc%407uw6jyyxuyf7
---
src/backend/access/heap/pruneheap.c | 86 +++++++++++++---------------
src/backend/access/heap/vacuumlazy.c | 16 ++++--
src/include/access/heapam.h | 62 ++++++++++++++++----
src/tools/pgindent/typedefs.list | 1 +
4 files changed, 101 insertions(+), 64 deletions(-)
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index 231bea679c6..450b2eb6494 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -258,15 +258,23 @@ heap_page_prune_opt(Relation relation, Buffer buffer)
if (PageIsFull(page) || PageGetHeapFreeSpace(page) < minfree)
{
OffsetNumber dummy_off_loc;
+ PruneFreezeParams params;
PruneFreezeResult presult;
+ params.relation = relation;
+ params.buffer = buffer;
+ params.reason = PRUNE_ON_ACCESS;
+ params.vistest = vistest;
+ params.cutoffs = NULL;
+
/*
* For now, pass mark_unused_now as false regardless of whether or
* not the relation has indexes, since we cannot safely determine
* that during on-access pruning with the current implementation.
*/
- heap_page_prune_and_freeze(relation, buffer, vistest, 0,
- NULL, &presult, PRUNE_ON_ACCESS, &dummy_off_loc, NULL, NULL);
+ params.options = 0;
+
+ heap_page_prune_and_freeze(¶ms, &presult, &dummy_off_loc, NULL, NULL);
/*
* Report the number of tuples reclaimed to pgstats. This is
@@ -419,60 +427,43 @@ heap_page_will_freeze(Relation relation, Buffer buffer,
* also need to account for a reduction in the length of the line pointer
* array following array truncation by us.
*
- * If the HEAP_PRUNE_FREEZE option is set, we will also freeze tuples if it's
- * required in order to advance relfrozenxid / relminmxid, or if it's
- * considered advantageous for overall system performance to do so now. The
- * 'cutoffs', 'presult', 'new_relfrozen_xid' and 'new_relmin_mxid' arguments
- * are required when freezing. When HEAP_PRUNE_FREEZE option is set, we also
- * set presult->all_visible and presult->all_frozen on exit, to indicate if
- * the VM bits can be set. They are always set to false when the
- * HEAP_PRUNE_FREEZE option is not set, because at the moment only callers
- * that also freeze need that information.
- *
- * vistest is used to distinguish whether tuples are DEAD or RECENTLY_DEAD
- * (see heap_prune_satisfies_vacuum).
+ * params contains the input parameters used to control freezing and pruning
+ * behavior. See the definition of PruneFreezeParams for more on what each
+ * parameter does.
*
- * options:
- * MARK_UNUSED_NOW indicates that dead items can be set LP_UNUSED during
- * pruning.
- *
- * FREEZE indicates that we will also freeze tuples, and will return
- * 'all_visible', 'all_frozen' flags to the caller.
- *
- * cutoffs contains the freeze cutoffs, established by VACUUM at the beginning
- * of vacuuming the relation. Required if HEAP_PRUNE_FREEZE option is set.
- * cutoffs->OldestXmin is also used to determine if dead tuples are
- * HEAPTUPLE_RECENTLY_DEAD or HEAPTUPLE_DEAD.
+ * If the HEAP_PRUNE_FREEZE option is set in params, we will freeze tuples if
+ * it's required in order to advance relfrozenxid / relminmxid, or if it's
+ * considered advantageous for overall system performance to do so now. The
+ * 'params.cutoffs', 'presult', 'new_relfrozen_xid' and 'new_relmin_mxid'
+ * arguments are required when freezing. When HEAP_PRUNE_FREEZE option is
+ * passed, we also set presult->all_visible and presult->all_frozen on exit,
+ * to indicate if the VM bits can be set. They are always set to false when
+ * the HEAP_PRUNE_FREEZE option is not passed, because at the moment only
+ * callers that also freeze need that information.
*
* presult contains output parameters needed by callers, such as the number of
* tuples removed and the offsets of dead items on the page after pruning.
* heap_page_prune_and_freeze() is responsible for initializing it. Required
* by all callers.
*
- * reason indicates why the pruning is performed. It is included in the WAL
- * record for debugging and analysis purposes, but otherwise has no effect.
- *
* off_loc is the offset location required by the caller to use in error
* callback.
*
* new_relfrozen_xid and new_relmin_mxid must provided by the caller if the
- * HEAP_PRUNE_FREEZE option is set. On entry, they contain the oldest XID and
- * multi-XID seen on the relation so far. They will be updated with oldest
- * values present on the page after pruning. After processing the whole
- * relation, VACUUM can use these values as the new relfrozenxid/relminmxid
- * for the relation.
+ * HEAP_PRUNE_FREEZE option is set in params. On entry, they contain the
+ * oldest XID and multi-XID seen on the relation so far. They will be updated
+ * with oldest values present on the page after pruning. After processing the
+ * whole relation, VACUUM can use these values as the new
+ * relfrozenxid/relminmxid for the relation.
*/
void
-heap_page_prune_and_freeze(Relation relation, Buffer buffer,
- GlobalVisState *vistest,
- int options,
- struct VacuumCutoffs *cutoffs,
+heap_page_prune_and_freeze(PruneFreezeParams *params,
PruneFreezeResult *presult,
- PruneReason reason,
OffsetNumber *off_loc,
TransactionId *new_relfrozen_xid,
MultiXactId *new_relmin_mxid)
{
+ Buffer buffer = params->buffer;
Page page = BufferGetPage(buffer);
BlockNumber blockno = BufferGetBlockNumber(buffer);
OffsetNumber offnum,
@@ -486,10 +477,11 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
int64 fpi_before = pgWalUsage.wal_fpi;
/* Copy parameters to prstate */
- prstate.vistest = vistest;
- prstate.mark_unused_now = (options & HEAP_PAGE_PRUNE_MARK_UNUSED_NOW) != 0;
- prstate.attempt_freeze = (options & HEAP_PAGE_PRUNE_FREEZE) != 0;
- prstate.cutoffs = cutoffs;
+ prstate.vistest = params->vistest;
+ prstate.mark_unused_now =
+ (params->options & HEAP_PAGE_PRUNE_MARK_UNUSED_NOW) != 0;
+ prstate.attempt_freeze = (params->options & HEAP_PAGE_PRUNE_FREEZE) != 0;
+ prstate.cutoffs = params->cutoffs;
/*
* Our strategy is to scan the page and make lists of items to change,
@@ -583,7 +575,7 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
prstate.visibility_cutoff_xid = InvalidTransactionId;
maxoff = PageGetMaxOffsetNumber(page);
- tup.t_tableOid = RelationGetRelid(relation);
+ tup.t_tableOid = RelationGetRelid(params->relation);
/*
* Determine HTSV for all tuples, and queue them up for processing as HOT
@@ -786,7 +778,7 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
* Decide if we want to go ahead with freezing according to the freeze
* plans we prepared, or not.
*/
- do_freeze = heap_page_will_freeze(relation, buffer,
+ do_freeze = heap_page_will_freeze(params->relation, buffer,
did_tuple_hint_fpi,
do_prune,
do_hint_prune,
@@ -838,7 +830,7 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
/*
* Emit a WAL XLOG_HEAP2_PRUNE* record showing what we did
*/
- if (RelationNeedsWAL(relation))
+ if (RelationNeedsWAL(params->relation))
{
/*
* The snapshotConflictHorizon for the whole record should be the
@@ -876,11 +868,11 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
else
conflict_xid = prstate.latest_xid_removed;
- log_heap_prune_and_freeze(relation, buffer,
+ log_heap_prune_and_freeze(params->relation, buffer,
InvalidBuffer, /* vmbuffer */
0, /* vmflags */
conflict_xid,
- true, reason,
+ true, params->reason,
prstate.frozen, prstate.nfrozen,
prstate.redirected, prstate.nredirected,
prstate.nowdead, prstate.ndead,
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index 61fe623cc60..e55be07cae4 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -1965,10 +1965,16 @@ lazy_scan_prune(LVRelState *vacrel,
{
Relation rel = vacrel->rel;
PruneFreezeResult presult;
- int prune_options = 0;
+ PruneFreezeParams params;
Assert(BufferGetBlockNumber(buf) == blkno);
+ params.relation = rel;
+ params.buffer = buf;
+ params.reason = PRUNE_VACUUM_SCAN;
+ params.cutoffs = &vacrel->cutoffs;
+ params.vistest = vacrel->vistest;
+
/*
* Prune all HOT-update chains and potentially freeze tuples on this page.
*
@@ -1984,12 +1990,12 @@ lazy_scan_prune(LVRelState *vacrel,
* tuples. Pruning will have determined whether or not the page is
* all-visible.
*/
- prune_options = HEAP_PAGE_PRUNE_FREEZE;
+ params.options = HEAP_PAGE_PRUNE_FREEZE;
if (vacrel->nindexes == 0)
- prune_options |= HEAP_PAGE_PRUNE_MARK_UNUSED_NOW;
+ params.options |= HEAP_PAGE_PRUNE_MARK_UNUSED_NOW;
- heap_page_prune_and_freeze(rel, buf, vacrel->vistest, prune_options,
- &vacrel->cutoffs, &presult, PRUNE_VACUUM_SCAN,
+ heap_page_prune_and_freeze(¶ms,
+ &presult,
&vacrel->offnum,
&vacrel->NewRelfrozenXid, &vacrel->NewRelminMxid);
diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h
index 909db73b7bb..b0b6d3552a6 100644
--- a/src/include/access/heapam.h
+++ b/src/include/access/heapam.h
@@ -221,6 +221,55 @@ typedef struct HeapPageFreeze
} HeapPageFreeze;
+
+/* 'reason' codes for heap_page_prune_and_freeze() */
+typedef enum
+{
+ PRUNE_ON_ACCESS, /* on-access pruning */
+ PRUNE_VACUUM_SCAN, /* VACUUM 1st heap pass */
+ PRUNE_VACUUM_CLEANUP, /* VACUUM 2nd heap pass */
+} PruneReason;
+
+/*
+ * Input parameters to heap_page_prune_and_freeze()
+ */
+typedef struct PruneFreezeParams
+{
+ Relation relation; /* relation containing buffer to be pruned */
+ Buffer buffer; /* buffer to be pruned */
+
+ /*
+ * The reason pruning was performed. It is used to set the WAL record
+ * opcode which is used for debugging and analysis purposes.
+ */
+ PruneReason reason;
+
+ /*
+ * Contains flag bits:
+ *
+ * MARK_UNUSED_NOW indicates that dead items can be set LP_UNUSED during
+ * pruning.
+ *
+ * FREEZE indicates that we will also freeze tuples, and will return
+ * 'all_visible', 'all_frozen' flags to the caller.
+ */
+ int options;
+
+ /*
+ * vistest is used to distinguish whether tuples are DEAD or RECENTLY_DEAD
+ * (see heap_prune_satisfies_vacuum).
+ */
+ GlobalVisState *vistest;
+
+ /*
+ * cutoffs contains the freeze cutoffs, established by VACUUM at the
+ * beginning of vacuuming the relation. Required if HEAP_PRUNE_FREEZE
+ * option is set. cutoffs->OldestXmin is also used to determine if dead
+ * tuples are HEAPTUPLE_RECENTLY_DEAD or HEAPTUPLE_DEAD.
+ */
+ struct VacuumCutoffs *cutoffs;
+} PruneFreezeParams;
+
/*
* Per-page state returned by heap_page_prune_and_freeze()
*/
@@ -264,13 +313,6 @@ typedef struct PruneFreezeResult
OffsetNumber deadoffsets[MaxHeapTuplesPerPage];
} PruneFreezeResult;
-/* 'reason' codes for heap_page_prune_and_freeze() */
-typedef enum
-{
- PRUNE_ON_ACCESS, /* on-access pruning */
- PRUNE_VACUUM_SCAN, /* VACUUM 1st heap pass */
- PRUNE_VACUUM_CLEANUP, /* VACUUM 2nd heap pass */
-} PruneReason;
/* ----------------
* function prototypes for heap access method
@@ -367,12 +409,8 @@ extern TransactionId heap_index_delete_tuples(Relation rel,
/* in heap/pruneheap.c */
extern void heap_page_prune_opt(Relation relation, Buffer buffer);
-extern void heap_page_prune_and_freeze(Relation relation, Buffer buffer,
- GlobalVisState *vistest,
- int options,
- struct VacuumCutoffs *cutoffs,
+extern void heap_page_prune_and_freeze(PruneFreezeParams *params,
PruneFreezeResult *presult,
- PruneReason reason,
OffsetNumber *off_loc,
TransactionId *new_relfrozen_xid,
MultiXactId *new_relmin_mxid);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 018b5919cf6..a384171de0d 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2343,6 +2343,7 @@ ProjectionPath
PromptInterruptContext
ProtocolVersion
PrsStorage
+PruneFreezeParams
PruneFreezeResult
PruneReason
PruneState
--
2.43.0
[text/x-patch] v19-0002-Keep-all_frozen-updated-in-heap_page_prune_and_f.patch (5.3K, 3-v19-0002-Keep-all_frozen-updated-in-heap_page_prune_and_f.patch)
download | inline diff:
From f179a5493c9671f9c8eca9231292d3a48bf7153c Mon Sep 17 00:00:00 2001
From: Melanie Plageman <[email protected]>
Date: Tue, 14 Oct 2025 14:55:40 -0400
Subject: [PATCH v19 02/12] Keep all_frozen updated in
heap_page_prune_and_freeze
Previously, we relied on all_visible and all_frozen being used together
to ensure that all_frozen was correct, but it is better to keep both
fields updated.
Future changes will separate their usage, so we should not depend on
all_visible for the validity of all_frozen.
---
src/backend/access/heap/pruneheap.c | 22 +++++++++++-----------
src/backend/access/heap/vacuumlazy.c | 9 ++++-----
2 files changed, 15 insertions(+), 16 deletions(-)
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index 450b2eb6494..daa719fc2a1 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -143,10 +143,6 @@ typedef struct
* whether to freeze the page or not. The all_visible and all_frozen
* values returned to the caller are adjusted to include LP_DEAD items at
* the end.
- *
- * all_frozen should only be considered valid if all_visible is also set;
- * we don't bother to clear the all_frozen flag every time we clear the
- * all_visible flag.
*/
bool all_visible;
bool all_frozen;
@@ -361,8 +357,10 @@ heap_page_will_freeze(Relation relation, Buffer buffer,
* anymore. The opportunistic freeze heuristic must be improved;
* however, for now, try to approximate the old logic.
*/
- if (prstate->all_visible && prstate->all_frozen && prstate->nfrozen > 0)
+ if (prstate->all_frozen && prstate->nfrozen > 0)
{
+ Assert(prstate->all_visible);
+
/*
* Freezing would make the page all-frozen. Have already emitted
* an FPI or will do so anyway?
@@ -784,6 +782,8 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
do_hint_prune,
&prstate);
+ Assert(!prstate.all_frozen || prstate.all_visible);
+
/* Any error while applying the changes is critical */
START_CRIT_SECTION();
@@ -853,7 +853,7 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
*/
if (do_freeze)
{
- if (prstate.all_visible && prstate.all_frozen)
+ if (prstate.all_frozen)
frz_conflict_horizon = prstate.visibility_cutoff_xid;
else
{
@@ -1418,7 +1418,7 @@ heap_prune_record_unchanged_lp_normal(Page page, PruneState *prstate, OffsetNumb
if (!HeapTupleHeaderXminCommitted(htup))
{
- prstate->all_visible = false;
+ prstate->all_visible = prstate->all_frozen = false;
break;
}
@@ -1440,7 +1440,7 @@ heap_prune_record_unchanged_lp_normal(Page page, PruneState *prstate, OffsetNumb
Assert(prstate->cutoffs);
if (!TransactionIdPrecedes(xmin, prstate->cutoffs->OldestXmin))
{
- prstate->all_visible = false;
+ prstate->all_visible = prstate->all_frozen = false;
break;
}
@@ -1453,7 +1453,7 @@ heap_prune_record_unchanged_lp_normal(Page page, PruneState *prstate, OffsetNumb
case HEAPTUPLE_RECENTLY_DEAD:
prstate->recently_dead_tuples++;
- prstate->all_visible = false;
+ prstate->all_visible = prstate->all_frozen = false;
/*
* This tuple will soon become DEAD. Update the hint field so
@@ -1472,7 +1472,7 @@ heap_prune_record_unchanged_lp_normal(Page page, PruneState *prstate, OffsetNumb
* assumption is a bit shaky, but it is what acquire_sample_rows()
* does, so be consistent.
*/
- prstate->all_visible = false;
+ prstate->all_visible = prstate->all_frozen = false;
/*
* If we wanted to optimize for aborts, we might consider marking
@@ -1490,7 +1490,7 @@ heap_prune_record_unchanged_lp_normal(Page page, PruneState *prstate, OffsetNumb
* will commit and update the counters after we report.
*/
prstate->live_tuples++;
- prstate->all_visible = false;
+ prstate->all_visible = prstate->all_frozen = false;
/*
* This tuple may soon become DEAD. Update the hint field so that
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index e55be07cae4..670a7424b15 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -2021,7 +2021,6 @@ lazy_scan_prune(LVRelState *vacrel,
* agreement with heap_page_is_all_visible() using an assertion.
*/
#ifdef USE_ASSERT_CHECKING
- /* Note that all_frozen value does not matter when !all_visible */
if (presult.all_visible)
{
TransactionId debug_cutoff;
@@ -2075,6 +2074,7 @@ lazy_scan_prune(LVRelState *vacrel,
*has_lpdead_items = (presult.lpdead_items > 0);
Assert(!presult.all_visible || !(*has_lpdead_items));
+ Assert(!presult.all_frozen || presult.all_visible);
/*
* Handle setting visibility map bit based on information from the VM (as
@@ -2180,11 +2180,10 @@ lazy_scan_prune(LVRelState *vacrel,
/*
* If the all-visible page is all-frozen but not marked as such yet, mark
- * it as all-frozen. Note that all_frozen is only valid if all_visible is
- * true, so we must check both all_visible and all_frozen.
+ * it as all-frozen.
*/
- else if (all_visible_according_to_vm && presult.all_visible &&
- presult.all_frozen && !VM_ALL_FROZEN(vacrel->rel, blkno, &vmbuffer))
+ else if (all_visible_according_to_vm && presult.all_frozen &&
+ !VM_ALL_FROZEN(vacrel->rel, blkno, &vmbuffer))
{
uint8 old_vmbits;
--
2.43.0
[text/x-patch] v19-0003-Update-PruneState.all_-visible-frozen-earlier-in.patch (9.7K, 4-v19-0003-Update-PruneState.all_-visible-frozen-earlier-in.patch)
download | inline diff:
From c27ab39e739acf7e96d1f7e81df91fc2b2b7fe43 Mon Sep 17 00:00:00 2001
From: Melanie Plageman <[email protected]>
Date: Tue, 14 Oct 2025 15:21:49 -0400
Subject: [PATCH v19 03/12] Update PruneState.all_[visible|frozen] earlier in
pruning
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
In the prune/freeze path, we currently delay clearing all_visible and
all_frozen in the presence of dead items. This allows opportunistic
freezing if the page would otherwise be fully frozen, since those dead
items are later removed in vacuum’s third phase.
To move the VM update into the same WAL record that
prunes and freezes tuples, we must know whether the page will
be marked all-visible/all-frozen before emitting WAL.
The only barrier to updating these flags immediately after deciding
whether to opportunistically freeze is that we previously used
all_frozen to compute the snapshot conflict horizon when freezing
tuples. By determining the cutoff earlier, we can update the flags
immediately after making the freeze decision.
This is required to set the VM in the XLOG_HEAP2_PRUNE_VACUUM_SCAN
record emitted by pruning and freezing.
---
src/backend/access/heap/pruneheap.c | 117 ++++++++++++++--------------
1 file changed, 57 insertions(+), 60 deletions(-)
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index daa719fc2a1..ef8861022f1 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -138,11 +138,11 @@ typedef struct
* bits. It is only valid if we froze some tuples, and all_frozen is
* true.
*
- * NOTE: all_visible and all_frozen don't include LP_DEAD items. That's
- * convenient for heap_page_prune_and_freeze(), to use them to decide
- * whether to freeze the page or not. The all_visible and all_frozen
- * values returned to the caller are adjusted to include LP_DEAD items at
- * the end.
+ * NOTE: all_visible and all_frozen initially don't include LP_DEAD items.
+ * That's convenient for heap_page_prune_and_freeze() to use them to
+ * decide whether to freeze the page or not. The all_visible and
+ * all_frozen values returned to the caller are adjusted to include
+ * LP_DEAD items after we determine whether to opportunistically freeze.
*/
bool all_visible;
bool all_frozen;
@@ -175,7 +175,7 @@ static void page_verify_redirects(Page page);
static bool heap_page_will_freeze(Relation relation, Buffer buffer,
bool did_tuple_hint_fpi, bool do_prune, bool do_hint_prune,
- PruneState *prstate);
+ PruneState *prstate, TransactionId *frz_conflict_horizon);
/*
@@ -308,7 +308,9 @@ heap_page_prune_opt(Relation relation, Buffer buffer)
* performs several pre-freeze checks.
*
* The values of do_prune, do_hint_prune, and did_tuple_hint_fpi must be
- * determined before calling this function.
+ * determined before calling this function. *frz_conflict_horizon is set to
+ * the snapshot conflict horizon we for the WAL record should we decide to
+ * freeze tuples.
*
* prstate is both an input and output parameter.
*
@@ -320,7 +322,8 @@ heap_page_will_freeze(Relation relation, Buffer buffer,
bool did_tuple_hint_fpi,
bool do_prune,
bool do_hint_prune,
- PruneState *prstate)
+ PruneState *prstate,
+ TransactionId *frz_conflict_horizon)
{
bool do_freeze = false;
@@ -390,6 +393,22 @@ heap_page_will_freeze(Relation relation, Buffer buffer,
* critical section.
*/
heap_pre_freeze_checks(buffer, prstate->frozen, prstate->nfrozen);
+
+ /*
+ * Calculate what the snapshot conflict horizon should be for a record
+ * freezing tuples. 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.
+ */
+ if (prstate->all_frozen)
+ *frz_conflict_horizon = prstate->visibility_cutoff_xid;
+ else
+ {
+ /* Avoids false conflicts when hot_standby_feedback in use */
+ *frz_conflict_horizon = prstate->cutoffs->OldestXmin;
+ TransactionIdRetreat(*frz_conflict_horizon);
+ }
}
else if (prstate->nfrozen > 0)
{
@@ -434,10 +453,11 @@ heap_page_will_freeze(Relation relation, Buffer buffer,
* considered advantageous for overall system performance to do so now. The
* 'params.cutoffs', 'presult', 'new_relfrozen_xid' and 'new_relmin_mxid'
* arguments are required when freezing. When HEAP_PRUNE_FREEZE option is
- * passed, we also set presult->all_visible and presult->all_frozen on exit,
- * to indicate if the VM bits can be set. They are always set to false when
- * the HEAP_PRUNE_FREEZE option is not passed, because at the moment only
- * callers that also freeze need that information.
+ * passed, we also set presult->all_visible and presult->all_frozen after
+ * determining whether or not to opporunistically freeze, to indicate if the
+ * VM bits can be set. They are always set to false when the
+ * HEAP_PRUNE_FREEZE option is not passed, because at the moment only callers
+ * that also freeze need that information.
*
* presult contains output parameters needed by callers, such as the number of
* tuples removed and the offsets of dead items on the page after pruning.
@@ -473,6 +493,7 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
bool do_hint_prune;
bool did_tuple_hint_fpi;
int64 fpi_before = pgWalUsage.wal_fpi;
+ TransactionId frz_conflict_horizon = InvalidTransactionId;
/* Copy parameters to prstate */
prstate.vistest = params->vistest;
@@ -542,10 +563,10 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
* are tuples present that are not visible to everyone or if there are
* dead tuples which are not yet removable. However, dead tuples which
* will be removed by the end of vacuuming should not preclude us from
- * opportunistically freezing. Because of that, we do not clear
- * all_visible when we see LP_DEAD items. We fix that at the end of the
- * function, when we return the value to the caller, so that the caller
- * doesn't set the VM bit incorrectly.
+ * opportunistically freezing. Because of that, we do not immediately
+ * clear all_visible when we see LP_DEAD items. We fix that after
+ * scanning the line pointers, before we return the value to the caller,
+ * so that the caller doesn't set the VM bit incorrectly.
*/
if (prstate.attempt_freeze)
{
@@ -780,7 +801,24 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
did_tuple_hint_fpi,
do_prune,
do_hint_prune,
- &prstate);
+ &prstate,
+ &frz_conflict_horizon);
+
+ /*
+ * While scanning the line pointers, we did not clear
+ * all_visible/all_frozen when encountering LP_DEAD items because we
+ * wanted the decision whether or not to freeze the page to be unaffected
+ * by the short-term presence of LP_DEAD items. These LP_DEAD items are
+ * effectively assumed to be LP_UNUSED items in the making. It doesn't
+ * matter which vacuum heap pass (initial pass or final pass) ends up
+ * setting the page all-frozen, as long as the ongoing VACUUM does it.
+ *
+ * Now that we finished determining whether or not to freeze the page,
+ * update all_visible and all_frozen so that they reflect the true state
+ * of the page for setting PD_ALL_VISIBLE and VM bits.
+ */
+ if (prstate.lpdead_items > 0)
+ prstate.all_visible = prstate.all_frozen = false;
Assert(!prstate.all_frozen || prstate.all_visible);
@@ -842,27 +880,8 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
* on the standby with xids older than the youngest tuple this
* record will freeze will conflict.
*/
- TransactionId frz_conflict_horizon = InvalidTransactionId;
TransactionId conflict_xid;
- /*
- * 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.
- */
- if (do_freeze)
- {
- if (prstate.all_frozen)
- frz_conflict_horizon = prstate.visibility_cutoff_xid;
- else
- {
- /* Avoids false conflicts when hot_standby_feedback in use */
- frz_conflict_horizon = prstate.cutoffs->OldestXmin;
- TransactionIdRetreat(frz_conflict_horizon);
- }
- }
-
if (TransactionIdFollows(frz_conflict_horizon, prstate.latest_xid_removed))
conflict_xid = frz_conflict_horizon;
else
@@ -888,30 +907,8 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
presult->nfrozen = prstate.nfrozen;
presult->live_tuples = prstate.live_tuples;
presult->recently_dead_tuples = prstate.recently_dead_tuples;
-
- /*
- * It was convenient to ignore LP_DEAD items in all_visible earlier on to
- * make the choice of whether or not to freeze the page unaffected by the
- * short-term presence of LP_DEAD items. These LP_DEAD items were
- * effectively assumed to be LP_UNUSED items in the making. It doesn't
- * matter which vacuum heap pass (initial pass or final pass) ends up
- * setting the page all-frozen, as long as the ongoing VACUUM does it.
- *
- * Now that freezing has been finalized, unset all_visible if there are
- * any LP_DEAD items on the page. It needs to reflect the present state
- * of the page, as expected by our caller.
- */
- if (prstate.all_visible && prstate.lpdead_items == 0)
- {
- presult->all_visible = prstate.all_visible;
- presult->all_frozen = prstate.all_frozen;
- }
- else
- {
- presult->all_visible = false;
- presult->all_frozen = false;
- }
-
+ presult->all_visible = prstate.all_visible;
+ presult->all_frozen = prstate.all_frozen;
presult->hastup = prstate.hastup;
/*
--
2.43.0
[text/x-patch] v19-0004-Eliminate-XLOG_HEAP2_VISIBLE-from-vacuum-phase-I.patch (41.3K, 5-v19-0004-Eliminate-XLOG_HEAP2_VISIBLE-from-vacuum-phase-I.patch)
download | inline diff:
From 02c1c23779aa22e05dde52bb02701398f5261654 Mon Sep 17 00:00:00 2001
From: Melanie Plageman <[email protected]>
Date: Wed, 8 Oct 2025 15:39:01 -0400
Subject: [PATCH v19 04/12] Eliminate XLOG_HEAP2_VISIBLE from vacuum phase I
prune/freeze
Vacuum no longer emits a separate WAL record for each page set
all-visible or all-frozen during phase I. Instead, visibility map
updates are now included in the XLOG_HEAP2_PRUNE_VACUUM_SCAN record that
is already emitted for pruning and freezing.
Previously, heap_page_prune_and_freeze() determined whether a page was
all-visible, but the corresponding VM bits were only set later in
lazy_scan_prune(). Now the VM is updated immediately in
heap_page_prune_and_freeze(), at the same time as the heap
modifications.
This change applies only to vacuum phase I, not to pruning performed
during normal page access.
Author: Melanie Plageman <[email protected]>
Reviewed-by: Robert Haas <[email protected]>
Reviewed-by: Kirill Reshke <[email protected]>
Discussion: https://postgr.es/m/flat/CAAKRu_ZMw6Npd_qm2KM%2BFwQ3cMOMx1Dh3VMhp8-V7SOLxdK9-g%40mail.gmail.com
---
src/backend/access/heap/heapam_xlog.c | 37 ++-
src/backend/access/heap/pruneheap.c | 435 ++++++++++++++++++++------
src/backend/access/heap/vacuumlazy.c | 207 +-----------
src/include/access/heapam.h | 43 ++-
4 files changed, 422 insertions(+), 300 deletions(-)
diff --git a/src/backend/access/heap/heapam_xlog.c b/src/backend/access/heap/heapam_xlog.c
index 11cb3f74da5..2af724451c3 100644
--- a/src/backend/access/heap/heapam_xlog.c
+++ b/src/backend/access/heap/heapam_xlog.c
@@ -104,6 +104,8 @@ heap_xlog_prune_freeze(XLogReaderState *record)
OffsetNumber *frz_offsets;
char *dataptr = XLogRecGetBlockData(record, 0, &datalen);
bool do_prune;
+ bool set_lsn = false;
+ bool mark_buffer_dirty = false;
heap_xlog_deserialize_prune_and_freeze(dataptr, xlrec.flags,
&nplans, &plans, &frz_offsets,
@@ -157,17 +159,36 @@ heap_xlog_prune_freeze(XLogReaderState *record)
/* There should be no more data */
Assert((char *) frz_offsets == dataptr + datalen);
- if (vmflags & VISIBILITYMAP_VALID_BITS)
- PageSetAllVisible(page);
-
- MarkBufferDirty(buffer);
+ if (do_prune || nplans > 0)
+ mark_buffer_dirty = set_lsn = true;
/*
- * See log_heap_prune_and_freeze() for commentary on when we set the
- * heap page LSN.
+ * The critical integrity requirement here is that we must never end
+ * up with with the visibility map bit set and the page-level
+ * PD_ALL_VISIBLE bit clear. If that were to occur, a subsequent page
+ * modification would fail to clear the visibility map bit.
+ *
+ * vmflags may be nonzero with PD_ALL_VISIBLE already set (e.g. when
+ * marking an all-visible page all-frozen). If only the VM is updated,
+ * the heap page need not be dirtied.
*/
- if (do_prune || nplans > 0 ||
- ((vmflags & VISIBILITYMAP_VALID_BITS) && XLogHintBitIsNeeded()))
+ if ((vmflags & VISIBILITYMAP_VALID_BITS) && !PageIsAllVisible(page))
+ {
+ PageSetAllVisible(page);
+ mark_buffer_dirty = true;
+
+ /*
+ * See log_heap_prune_and_freeze() for commentary on when we set
+ * the heap page LSN.
+ */
+ if (XLogHintBitIsNeeded())
+ set_lsn = true;
+ }
+
+ if (mark_buffer_dirty)
+ MarkBufferDirty(buffer);
+
+ if (set_lsn)
PageSetLSN(page, lsn);
/*
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index ef8861022f1..8dafbd344d8 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -19,7 +19,7 @@
#include "access/htup_details.h"
#include "access/multixact.h"
#include "access/transam.h"
-#include "access/visibilitymapdefs.h"
+#include "access/visibilitymap.h"
#include "access/xlog.h"
#include "access/xloginsert.h"
#include "commands/vacuum.h"
@@ -44,6 +44,8 @@ typedef struct
bool mark_unused_now;
/* whether to attempt freezing tuples */
bool attempt_freeze;
+ /* whether or not to attempt updating the VM */
+ bool attempt_update_vm;
struct VacuumCutoffs *cutoffs;
/*-------------------------------------------------------
@@ -133,16 +135,17 @@ typedef struct
* all_visible and all_frozen indicate if the all-visible and all-frozen
* bits in the visibility map can be set for this page after pruning.
*
- * visibility_cutoff_xid is the newest xmin of live tuples on the page.
- * The caller can use it as the conflict horizon, when setting the VM
- * bits. It is only valid if we froze some tuples, and all_frozen is
- * true.
+ * visibility_cutoff_xid is the newest xmin of live tuples on the page. It
+ * can be used as the conflict horizon when setting the VM or when
+ * freezing all the tuples on the page. It is only valid when all the live
+ * tuples on the page are all-visible.
*
* NOTE: all_visible and all_frozen initially don't include LP_DEAD items.
* That's convenient for heap_page_prune_and_freeze() to use them to
- * decide whether to freeze the page or not. The all_visible and
- * all_frozen values returned to the caller are adjusted to include
- * LP_DEAD items after we determine whether to opportunistically freeze.
+ * decide whether to opportunistically freeze the page or not. The
+ * all_visible and all_frozen values ultimately used to set the VM are
+ * adjusted to include LP_DEAD items after we determine whether or not to
+ * opportunistically freeze.
*/
bool all_visible;
bool all_frozen;
@@ -173,10 +176,21 @@ static void heap_prune_record_unchanged_lp_redirect(PruneState *prstate, OffsetN
static void page_verify_redirects(Page page);
+static TransactionId get_conflict_xid(bool do_prune, bool do_freeze, bool do_set_vm,
+ TransactionId latest_xid_removed, TransactionId frz_conflict_horizon,
+ TransactionId visibility_cutoff_xid, bool blk_already_av,
+ bool set_blk_all_frozen);
static bool heap_page_will_freeze(Relation relation, Buffer buffer,
bool did_tuple_hint_fpi, bool do_prune, bool do_hint_prune,
PruneState *prstate, TransactionId *frz_conflict_horizon);
-
+static bool heap_page_will_set_vis(Relation relation,
+ BlockNumber heap_blk,
+ Buffer heap_buf,
+ Buffer vmbuffer,
+ bool blk_known_av,
+ const PruneState *prstate,
+ uint8 *vmflags,
+ bool *do_set_pd_vis);
/*
* Optionally prune and repair fragmentation in the specified page.
@@ -262,6 +276,8 @@ heap_page_prune_opt(Relation relation, Buffer buffer)
params.reason = PRUNE_ON_ACCESS;
params.vistest = vistest;
params.cutoffs = NULL;
+ params.vmbuffer = InvalidBuffer;
+ params.blk_known_av = false;
/*
* For now, pass mark_unused_now as false regardless of whether or
@@ -434,10 +450,108 @@ heap_page_will_freeze(Relation relation, Buffer buffer,
return do_freeze;
}
+/*
+ * Decide whether to set the visibility map bits for heap_blk, using
+ * information from PruneState and blk_known_av. Some callers may already
+ * have examined this page’s VM bits (e.g., VACUUM in the previous
+ * heap_vac_scan_next_block() call) and can pass that along.
+ *
+ * Returns true if one or both VM bits should be set, along with the desired
+ * flags in *vmflags. Also indicates via do_set_pd_vis whether PD_ALL_VISIBLE
+ * should be set on the heap page.
+ */
+static bool
+heap_page_will_set_vis(Relation relation,
+ BlockNumber heap_blk,
+ Buffer heap_buf,
+ Buffer vmbuffer,
+ bool blk_known_av,
+ const PruneState *prstate,
+ uint8 *vmflags,
+ bool *do_set_pd_vis)
+{
+ Page heap_page = BufferGetPage(heap_buf);
+ bool do_set_vm = false;
+
+ *do_set_pd_vis = false;
+
+ if (!prstate->attempt_update_vm)
+ {
+ Assert(!prstate->all_visible && !prstate->all_frozen);
+ Assert(*vmflags == 0);
+ return false;
+ }
+
+ if (prstate->all_visible && !PageIsAllVisible(heap_page))
+ *do_set_pd_vis = true;
+
+ if ((prstate->all_visible && !blk_known_av) ||
+ (prstate->all_frozen && !VM_ALL_FROZEN(relation, heap_blk, &vmbuffer)))
+ {
+ *vmflags = VISIBILITYMAP_ALL_VISIBLE;
+ if (prstate->all_frozen)
+ *vmflags |= VISIBILITYMAP_ALL_FROZEN;
+
+ do_set_vm = true;
+ }
+
+ /*
+ * Now handle two potential corruption cases:
+ *
+ * These do not need to happen in a critical section and are not
+ * WAL-logged.
+ *
+ * As of PostgreSQL 9.2, the visibility map bit should never be set if the
+ * page-level bit is clear. However, it's possible that in vacuum the bit
+ * got cleared after heap_vac_scan_next_block() was called, so we must
+ * recheck with buffer lock before concluding that the VM is corrupt.
+ */
+ else if (blk_known_av && !PageIsAllVisible(heap_page) &&
+ visibilitymap_get_status(relation, heap_blk, &vmbuffer) != 0)
+ {
+ ereport(WARNING,
+ (errcode(ERRCODE_DATA_CORRUPTED),
+ errmsg("page is not marked all-visible but visibility map bit is set in relation \"%s\" page %u",
+ RelationGetRelationName(relation), heap_blk)));
+
+ visibilitymap_clear(relation, heap_blk, vmbuffer,
+ VISIBILITYMAP_VALID_BITS);
+ }
+
+ /*
+ * It's possible for the value returned by
+ * GetOldestNonRemovableTransactionId() to move backwards, so it's not
+ * wrong for us to see tuples that appear to not be visible to everyone
+ * yet, while PD_ALL_VISIBLE is already set. The real safe xmin value
+ * never moves backwards, but GetOldestNonRemovableTransactionId() is
+ * conservative and sometimes returns a value that's unnecessarily small,
+ * so if we see that contradiction it just means that the tuples that we
+ * think are not visible to everyone yet actually are, and the
+ * PD_ALL_VISIBLE flag is correct.
+ *
+ * There should never be LP_DEAD items on a page with PD_ALL_VISIBLE set,
+ * however.
+ */
+ else if (prstate->lpdead_items > 0 && PageIsAllVisible(heap_page))
+ {
+ ereport(WARNING,
+ (errcode(ERRCODE_DATA_CORRUPTED),
+ errmsg("page containing LP_DEAD items is marked as all-visible in relation \"%s\" page %u",
+ RelationGetRelationName(relation), heap_blk)));
+
+ PageClearAllVisible(heap_page);
+ MarkBufferDirty(heap_buf);
+ visibilitymap_clear(relation, heap_blk, vmbuffer,
+ VISIBILITYMAP_VALID_BITS);
+ }
+
+ return do_set_vm;
+}
/*
* Prune and repair fragmentation and potentially freeze tuples on the
- * specified page.
+ * specified page. If the page's visibility status has changed, update it in
+ * the VM.
*
* Caller must have pin and buffer cleanup lock on the page. Note that we
* don't update the FSM information for page on caller's behalf. Caller might
@@ -452,12 +566,13 @@ heap_page_will_freeze(Relation relation, Buffer buffer,
* it's required in order to advance relfrozenxid / relminmxid, or if it's
* considered advantageous for overall system performance to do so now. The
* 'params.cutoffs', 'presult', 'new_relfrozen_xid' and 'new_relmin_mxid'
- * arguments are required when freezing. When HEAP_PRUNE_FREEZE option is
- * passed, we also set presult->all_visible and presult->all_frozen after
- * determining whether or not to opporunistically freeze, to indicate if the
- * VM bits can be set. They are always set to false when the
- * HEAP_PRUNE_FREEZE option is not passed, because at the moment only callers
- * that also freeze need that information.
+ * arguments are required when freezing.
+ *
+ * If HEAP_PAGE_PRUNE_UPDATE_VIS is set in params and the visibility status of
+ * the page has changed, we will update the VM at the same time as pruning and
+ * freezing the heap page. We will also update presult->old_vmbits and
+ * presult->new_vmbits with the state of the VM before and after updating it
+ * for the caller to use in bookkeeping.
*
* presult contains output parameters needed by callers, such as the number of
* tuples removed and the offsets of dead items on the page after pruning.
@@ -482,6 +597,7 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
MultiXactId *new_relmin_mxid)
{
Buffer buffer = params->buffer;
+ Buffer vmbuffer = params->vmbuffer;
Page page = BufferGetPage(buffer);
BlockNumber blockno = BufferGetBlockNumber(buffer);
OffsetNumber offnum,
@@ -491,15 +607,22 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
bool do_freeze;
bool do_prune;
bool do_hint_prune;
+ bool do_set_vm;
+ bool do_set_pd_vis;
bool did_tuple_hint_fpi;
int64 fpi_before = pgWalUsage.wal_fpi;
TransactionId frz_conflict_horizon = InvalidTransactionId;
+ TransactionId conflict_xid = InvalidTransactionId;
+ uint8 new_vmbits = 0;
+ uint8 old_vmbits = 0;
/* Copy parameters to prstate */
prstate.vistest = params->vistest;
prstate.mark_unused_now =
(params->options & HEAP_PAGE_PRUNE_MARK_UNUSED_NOW) != 0;
prstate.attempt_freeze = (params->options & HEAP_PAGE_PRUNE_FREEZE) != 0;
+ prstate.attempt_update_vm =
+ (params->options & HEAP_PAGE_PRUNE_UPDATE_VIS) != 0;
prstate.cutoffs = params->cutoffs;
/*
@@ -546,50 +669,54 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
prstate.deadoffsets = presult->deadoffsets;
/*
- * Caller may update the VM after we're done. We can keep track of
- * whether the page will be all-visible and all-frozen after pruning and
- * freezing to help the caller to do that.
+ * Track whether the page could be marked all-visible and/or all-frozen.
+ * This information is used for opportunistic freezing and for updating
+ * the visibility map (VM) if requested by the caller.
+ *
+ * Currently, only VACUUM performs freezing, but other callers may in the
+ * future. Visibility bookkeeping is required not just for setting the VM
+ * bits, but also for opportunistic freezing: we only consider freezing if
+ * the page would become all-frozen, or if it would be all-frozen except
+ * for dead tuples that VACUUM will remove. If attempt_update_vm is false,
+ * we will not set the VM bit even if the page is found to be all-visible.
+ *
+ * If HEAP_PAGE_PRUNE_UPDATE_VIS is passed without HEAP_PAGE_PRUNE_FREEZE,
+ * prstate.all_frozen must be initialized to false, since we will not call
+ * heap_prepare_freeze_tuple() for each tuple.
*
- * Currently, only VACUUM sets the VM bits. To save the effort, only do
- * the bookkeeping if the caller needs it. Currently, that's tied to
- * HEAP_PAGE_PRUNE_FREEZE, but it could be a separate flag if you wanted
- * to update the VM bits without also freezing or freeze without also
- * setting the VM bits.
+ * Dead tuples that will be removed by the end of vacuum should not
+ * prevent opportunistic freezing. Therefore, we do not clear all_visible
+ * when we encounter LP_DEAD items. Instead, we correct all_visible after
+ * deciding whether to freeze, but before updating the VM, to avoid
+ * setting the VM bit incorrectly.
*
- * In addition to telling the caller whether it can set the VM bit, we
- * also use 'all_visible' and 'all_frozen' for our own decision-making. If
- * the whole page would become frozen, we consider opportunistically
- * freezing tuples. We will not be able to freeze the whole page if there
- * are tuples present that are not visible to everyone or if there are
- * dead tuples which are not yet removable. However, dead tuples which
- * will be removed by the end of vacuuming should not preclude us from
- * opportunistically freezing. Because of that, we do not immediately
- * clear all_visible when we see LP_DEAD items. We fix that after
- * scanning the line pointers, before we return the value to the caller,
- * so that the caller doesn't set the VM bit incorrectly.
+ * If neither freezing nor VM updates are requested, we skip the extra
+ * bookkeeping. In this case, initializing all_visible to false allows
+ * heap_prune_record_unchanged_lp_normal() to bypass unnecessary work.
*/
if (prstate.attempt_freeze)
{
prstate.all_visible = true;
prstate.all_frozen = true;
}
+ else if (prstate.attempt_update_vm)
+ {
+ prstate.all_visible = true;
+ prstate.all_frozen = false;
+ }
else
{
- /*
- * Initializing to false allows skipping the work to update them in
- * heap_prune_record_unchanged_lp_normal().
- */
prstate.all_visible = false;
prstate.all_frozen = false;
}
/*
- * The visibility cutoff xid is the newest xmin of live tuples on the
- * page. In the common case, this will be set as the conflict horizon the
- * caller can use for updating the VM. If, at the end of freezing and
- * pruning, the page is all-frozen, there is no possibility that any
- * running transaction on the standby does not see tuples on the page as
- * all-visible, so the conflict horizon remains InvalidTransactionId.
+ * The visibility cutoff xid is the newest xmin of live, committed tuples
+ * older than OldestXmin on the page. This field is only kept up-to-date
+ * if the page is all-visible. As soon as a tuple is encountered that is
+ * not visible to all, this field is unmaintained. As long as it is
+ * maintained, it can be used to calculate the snapshot conflict horizon
+ * when updating the VM and/or freezing all the tuples on the page.
*/
prstate.visibility_cutoff_xid = InvalidTransactionId;
@@ -821,6 +948,34 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
prstate.all_visible = prstate.all_frozen = false;
Assert(!prstate.all_frozen || prstate.all_visible);
+ Assert(!prstate.all_visible || (prstate.lpdead_items == 0));
+
+ /*
+ * Decide whether to set the page-level PD_ALL_VISIBLE bit and the VM bits
+ * based on information from the VM and the all_visible/all_frozen flags.
+ *
+ * While it is valid for PD_ALL_VISIBLE to be set when the corresponding
+ * VM bit is clear, we strongly prefer to keep them in sync.
+ *
+ * Accordingly, we also allow updating only the VM when PD_ALL_VISIBLE has
+ * already been set. Setting only the VM is most common when setting an
+ * already all-visible page all-frozen.
+ */
+ do_set_vm = heap_page_will_set_vis(params->relation,
+ blockno, buffer, vmbuffer, params->blk_known_av,
+ &prstate, &new_vmbits, &do_set_pd_vis);
+
+ /* We should only set the VM if PD_ALL_VISIBLE is set or will be */
+ Assert(!do_set_vm || do_set_pd_vis || PageIsAllVisible(page));
+
+ conflict_xid = get_conflict_xid(do_prune, do_freeze, do_set_vm,
+ prstate.latest_xid_removed, frz_conflict_horizon,
+ prstate.visibility_cutoff_xid, params->blk_known_av,
+ (do_set_vm && (new_vmbits & VISIBILITYMAP_ALL_FROZEN)));
+
+ /* Lock vmbuffer before entering a critical section */
+ if (do_set_vm)
+ LockBuffer(vmbuffer, BUFFER_LOCK_EXCLUSIVE);
/* Any error while applying the changes is critical */
START_CRIT_SECTION();
@@ -842,14 +997,17 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
/*
* If that's all we had to do to the page, this is a non-WAL-logged
- * hint. If we are going to freeze or prune the page, we will mark
- * the buffer dirty below.
+ * hint. If we are going to freeze or prune the page or set
+ * PD_ALL_VISIBLE, we will mark the buffer dirty below.
+ *
+ * Setting PD_ALL_VISIBLE is fully WAL-logged because it is forbidden
+ * for the VM to be set and PD_ALL_VISIBLE to be clear.
*/
- if (!do_freeze && !do_prune)
+ if (!do_freeze && !do_prune && !do_set_pd_vis)
MarkBufferDirtyHint(buffer, true);
}
- if (do_prune || do_freeze)
+ if (do_prune || do_freeze || do_set_vm)
{
/* Apply the planned item changes and repair page fragmentation. */
if (do_prune)
@@ -863,35 +1021,43 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
if (do_freeze)
heap_freeze_prepared_tuples(buffer, prstate.frozen, prstate.nfrozen);
- MarkBufferDirty(buffer);
+ if (do_set_pd_vis)
+ PageSetAllVisible(page);
- /*
- * Emit a WAL XLOG_HEAP2_PRUNE* record showing what we did
- */
- if (RelationNeedsWAL(params->relation))
+ if (do_prune || do_freeze || do_set_pd_vis)
+ MarkBufferDirty(buffer);
+
+ if (do_set_vm)
{
- /*
- * 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;
+ Assert(PageIsAllVisible(page));
- if (TransactionIdFollows(frz_conflict_horizon, prstate.latest_xid_removed))
- conflict_xid = frz_conflict_horizon;
- else
- conflict_xid = prstate.latest_xid_removed;
+ old_vmbits = visibilitymap_set_vmbits(blockno,
+ vmbuffer, new_vmbits,
+ params->relation->rd_locator);
+ if (old_vmbits == new_vmbits)
+ {
+ LockBuffer(vmbuffer, BUFFER_LOCK_UNLOCK);
+ /* Unset so we don't emit WAL since no change occurred */
+ do_set_vm = false;
+ }
+ }
+ /*
+ * Emit a WAL XLOG_HEAP2_PRUNE* record showing what we did. If we were
+ * only updating the VM and it turns out it was already set, we will
+ * have unset do_set_vm earlier. As such, check it again before
+ * emitting the record.
+ */
+ if (RelationNeedsWAL(params->relation) &&
+ (do_prune || do_freeze || do_set_vm))
+ {
log_heap_prune_and_freeze(params->relation, buffer,
- InvalidBuffer, /* vmbuffer */
- 0, /* vmflags */
+ do_set_vm ? vmbuffer : InvalidBuffer,
+ do_set_vm ? new_vmbits : 0,
conflict_xid,
- true, params->reason,
+ true, /* cleanup lock */
+ do_set_pd_vis,
+ params->reason,
prstate.frozen, prstate.nfrozen,
prstate.redirected, prstate.nredirected,
prstate.nowdead, prstate.ndead,
@@ -901,28 +1067,47 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
END_CRIT_SECTION();
+ if (do_set_vm)
+ LockBuffer(vmbuffer, BUFFER_LOCK_UNLOCK);
+
+ /*
+ * During its second pass over the heap, VACUUM calls
+ * heap_page_would_be_all_visible() to determine whether a page is
+ * all-visible and all-frozen. The logic here is similar. After completing
+ * pruning and freezing, use an assertion to verify that our results
+ * remain consistent with heap_page_would_be_all_visible().
+ */
+#ifdef USE_ASSERT_CHECKING
+ if (prstate.all_visible)
+ {
+ TransactionId debug_cutoff;
+ bool debug_all_frozen;
+
+ Assert(prstate.lpdead_items == 0);
+ Assert(prstate.cutoffs);
+
+ if (!heap_page_is_all_visible(params->relation, buffer,
+ prstate.cutoffs->OldestXmin,
+ &debug_all_frozen,
+ &debug_cutoff, off_loc))
+ Assert(false);
+
+ Assert(prstate.all_frozen == debug_all_frozen);
+
+ Assert(!TransactionIdIsValid(debug_cutoff) ||
+ debug_cutoff == prstate.visibility_cutoff_xid);
+ }
+#endif
+
/* Copy information back for caller */
presult->ndeleted = prstate.ndeleted;
presult->nnewlpdead = prstate.ndead;
presult->nfrozen = prstate.nfrozen;
presult->live_tuples = prstate.live_tuples;
presult->recently_dead_tuples = prstate.recently_dead_tuples;
- presult->all_visible = prstate.all_visible;
- presult->all_frozen = prstate.all_frozen;
presult->hastup = prstate.hastup;
-
- /*
- * 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
- * page is completely frozen, there can be no conflict and the
- * vm_conflict_horizon should remain InvalidTransactionId. This includes
- * the case that we just froze all the tuples; the prune-freeze record
- * included the conflict XID already so the caller doesn't need it.
- */
- if (presult->all_frozen)
- presult->vm_conflict_horizon = InvalidTransactionId;
- else
- presult->vm_conflict_horizon = prstate.visibility_cutoff_xid;
+ presult->new_vmbits = new_vmbits;
+ presult->old_vmbits = old_vmbits;
presult->lpdead_items = prstate.lpdead_items;
/* the presult->deadoffsets array was already filled in */
@@ -1413,6 +1598,8 @@ heap_prune_record_unchanged_lp_normal(Page page, PruneState *prstate, OffsetNumb
{
TransactionId xmin;
+ Assert(prstate->attempt_update_vm);
+
if (!HeapTupleHeaderXminCommitted(htup))
{
prstate->all_visible = prstate->all_frozen = false;
@@ -2058,6 +2245,65 @@ heap_log_freeze_plan(HeapTupleFreeze *tuples, int ntuples,
return nplans;
}
+/*
+ * Calculate the conflict horizon for the whole XLOG_HEAP2_PRUNE_VACUUM_SCAN
+ * record.
+ */
+static TransactionId
+get_conflict_xid(bool do_prune, bool do_freeze, bool do_set_vm,
+ TransactionId latest_xid_removed, TransactionId frz_conflict_horizon,
+ TransactionId visibility_cutoff_xid, bool blk_already_av,
+ bool set_blk_all_frozen)
+{
+ TransactionId conflict_xid;
+
+ /*
+ * We can omit the snapshot conflict horizon if we are not pruning or
+ * freezing any tuples and are setting an already all-visible page
+ * all-frozen in the VM. In this case, all of the tuples on the page must
+ * already be visible to all MVCC snapshots on the standby.
+ */
+ if (!do_prune && !do_freeze &&
+ do_set_vm && blk_already_av && set_blk_all_frozen)
+ return InvalidTransactionId;
+
+ /*
+ * 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.
+ */
+ conflict_xid = InvalidTransactionId;
+
+ /*
+ * If we are updating the VM, the conflict horizon is almost always the
+ * visibility cutoff XID.
+ *
+ * Separately, if we are freezing any tuples, as an optimization, we can
+ * use the visibility_cutoff_xid as the conflict horizon if the page will
+ * be all-frozen. This is true even if there are LP_DEAD line pointers
+ * because we ignored those when maintaining the visibility_cutoff_xid.
+ * This will have been calculated earlier as the frz_conflict_horizon when
+ * we determined we would freeze.
+ */
+ if (do_set_vm)
+ conflict_xid = visibility_cutoff_xid;
+ else if (do_freeze)
+ conflict_xid = frz_conflict_horizon;
+
+ /*
+ * If we are removing tuples with a younger xmax than our so far
+ * calculated conflict_xid, we must use this as our horizon.
+ */
+ if (TransactionIdFollows(latest_xid_removed, conflict_xid))
+ conflict_xid = latest_xid_removed;
+
+ return conflict_xid;
+}
+
/*
* Write an XLOG_HEAP2_PRUNE* WAL record
*
@@ -2082,6 +2328,15 @@ heap_log_freeze_plan(HeapTupleFreeze *tuples, int ntuples,
* case, vmbuffer should already have been updated and marked dirty and should
* still be pinned and locked.
*
+ * set_pd_all_vis indicates that we set PD_ALL_VISIBLE and thus should update
+ * the page LSN when checksums/wal_log_hints are enabled even if we did not
+ * prune or freeze tuples on the page.
+ *
+ * In some cases, such as when heap_page_prune_and_freeze() is setting an
+ * already marked all-visible page all-frozen, PD_ALL_VISIBLE may already be
+ * set. So, it is possible for vmflags to be non-zero and set_pd_all_vis to be
+ * false.
+ *
* Note: This function scribbles on the 'frozen' array.
*
* Note: This is called in a critical section, so careful what you do here.
@@ -2091,6 +2346,7 @@ log_heap_prune_and_freeze(Relation relation, Buffer buffer,
Buffer vmbuffer, uint8 vmflags,
TransactionId conflict_xid,
bool cleanup_lock,
+ bool set_pd_all_vis,
PruneReason reason,
HeapTupleFreeze *frozen, int nfrozen,
OffsetNumber *redirected, int nredirected,
@@ -2127,7 +2383,7 @@ log_heap_prune_and_freeze(Relation relation, Buffer buffer,
*/
if (!do_prune &&
nfrozen == 0 &&
- (!do_set_vm || !XLogHintBitIsNeeded()))
+ (!set_pd_all_vis || !XLogHintBitIsNeeded()))
regbuf_flags_heap |= REGBUF_NO_IMAGE;
/*
@@ -2245,7 +2501,8 @@ log_heap_prune_and_freeze(Relation relation, Buffer buffer,
* See comment at the top of the function about regbuf_flags_heap for
* details on when we can advance the page LSN.
*/
- if (do_prune || nfrozen > 0 || (do_set_vm && XLogHintBitIsNeeded()))
+ if (do_prune || nfrozen > 0 ||
+ (set_pd_all_vis && XLogHintBitIsNeeded()))
{
Assert(BufferIsDirty(buffer));
PageSetLSN(BufferGetPage(buffer), recptr);
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index 670a7424b15..60529fcf9d7 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -464,13 +464,6 @@ static void dead_items_add(LVRelState *vacrel, BlockNumber blkno, OffsetNumber *
static void dead_items_reset(LVRelState *vacrel);
static void dead_items_cleanup(LVRelState *vacrel);
-#ifdef USE_ASSERT_CHECKING
-static bool heap_page_is_all_visible(Relation rel, Buffer buf,
- TransactionId OldestXmin,
- bool *all_frozen,
- TransactionId *visibility_cutoff_xid,
- OffsetNumber *logging_offnum);
-#endif
static bool heap_page_would_be_all_visible(Relation rel, Buffer buf,
TransactionId OldestXmin,
OffsetNumber *deadoffsets,
@@ -1974,6 +1967,8 @@ lazy_scan_prune(LVRelState *vacrel,
params.reason = PRUNE_VACUUM_SCAN;
params.cutoffs = &vacrel->cutoffs;
params.vistest = vacrel->vistest;
+ params.vmbuffer = vmbuffer;
+ params.blk_known_av = all_visible_according_to_vm;
/*
* Prune all HOT-update chains and potentially freeze tuples on this page.
@@ -1990,7 +1985,7 @@ lazy_scan_prune(LVRelState *vacrel,
* tuples. Pruning will have determined whether or not the page is
* all-visible.
*/
- params.options = HEAP_PAGE_PRUNE_FREEZE;
+ params.options = HEAP_PAGE_PRUNE_FREEZE | HEAP_PAGE_PRUNE_UPDATE_VIS;
if (vacrel->nindexes == 0)
params.options |= HEAP_PAGE_PRUNE_MARK_UNUSED_NOW;
@@ -2013,33 +2008,6 @@ lazy_scan_prune(LVRelState *vacrel,
vacrel->new_frozen_tuple_pages++;
}
- /*
- * VACUUM will call heap_page_is_all_visible() during the second pass over
- * the heap to determine all_visible and all_frozen for the page -- this
- * is a specialized version of the logic from this function. Now that
- * we've finished pruning and freezing, make sure that we're in total
- * agreement with heap_page_is_all_visible() using an assertion.
- */
-#ifdef USE_ASSERT_CHECKING
- if (presult.all_visible)
- {
- TransactionId debug_cutoff;
- bool debug_all_frozen;
-
- Assert(presult.lpdead_items == 0);
-
- if (!heap_page_is_all_visible(vacrel->rel, buf,
- vacrel->cutoffs.OldestXmin, &debug_all_frozen,
- &debug_cutoff, &vacrel->offnum))
- Assert(false);
-
- Assert(presult.all_frozen == debug_all_frozen);
-
- Assert(!TransactionIdIsValid(debug_cutoff) ||
- debug_cutoff == presult.vm_conflict_horizon);
- }
-#endif
-
/*
* Now save details of the LP_DEAD items from the page in vacrel
*/
@@ -2073,168 +2041,26 @@ lazy_scan_prune(LVRelState *vacrel,
/* Did we find LP_DEAD items? */
*has_lpdead_items = (presult.lpdead_items > 0);
- Assert(!presult.all_visible || !(*has_lpdead_items));
- Assert(!presult.all_frozen || presult.all_visible);
-
/*
- * Handle setting visibility map bit based on information from the VM (as
- * of last heap_vac_scan_next_block() call), and from all_visible and
- * all_frozen variables
+ * For the purposes of logging, count whether or not the page was newly
+ * set all-visible and, potentially, all-frozen.
*/
- if (!all_visible_according_to_vm && presult.all_visible)
+ if ((presult.old_vmbits & VISIBILITYMAP_ALL_VISIBLE) == 0 &&
+ (presult.new_vmbits & VISIBILITYMAP_ALL_VISIBLE) != 0)
{
- uint8 old_vmbits;
- uint8 flags = VISIBILITYMAP_ALL_VISIBLE;
-
- if (presult.all_frozen)
- {
- Assert(!TransactionIdIsValid(presult.vm_conflict_horizon));
- flags |= VISIBILITYMAP_ALL_FROZEN;
- }
-
- /*
- * It should never be the case that the visibility map page is set
- * while the page-level bit is clear, but the reverse is allowed (if
- * checksums are not enabled). Regardless, set both bits so that we
- * get back in sync.
- *
- * NB: If the heap page is all-visible but the VM bit is not set, we
- * don't need to dirty the heap page. However, if checksums are
- * enabled, we do need to make sure that the heap page is dirtied
- * before passing it to visibilitymap_set(), because it may be logged.
- * Given that this situation should only happen in rare cases after a
- * crash, it is not worth optimizing.
- */
- PageSetAllVisible(page);
- MarkBufferDirty(buf);
- old_vmbits = visibilitymap_set(vacrel->rel, blkno, buf,
- InvalidXLogRecPtr,
- vmbuffer, presult.vm_conflict_horizon,
- flags);
-
- /*
- * If the page wasn't already set all-visible and/or all-frozen in the
- * VM, count it as newly set for logging.
- */
- if ((old_vmbits & VISIBILITYMAP_ALL_VISIBLE) == 0)
- {
- vacrel->vm_new_visible_pages++;
- if (presult.all_frozen)
- {
- vacrel->vm_new_visible_frozen_pages++;
- *vm_page_frozen = true;
- }
- }
- else if ((old_vmbits & VISIBILITYMAP_ALL_FROZEN) == 0 &&
- presult.all_frozen)
+ vacrel->vm_new_visible_pages++;
+ if ((presult.new_vmbits & VISIBILITYMAP_ALL_FROZEN) != 0)
{
- vacrel->vm_new_frozen_pages++;
+ vacrel->vm_new_visible_frozen_pages++;
*vm_page_frozen = true;
}
}
-
- /*
- * As of PostgreSQL 9.2, the visibility map bit should never be set if the
- * page-level bit is clear. However, it's possible that the bit got
- * cleared after heap_vac_scan_next_block() was called, so we must recheck
- * with buffer lock before concluding that the VM is corrupt.
- */
- else if (all_visible_according_to_vm && !PageIsAllVisible(page) &&
- visibilitymap_get_status(vacrel->rel, blkno, &vmbuffer) != 0)
+ else if ((presult.old_vmbits & VISIBILITYMAP_ALL_FROZEN) == 0 &&
+ (presult.new_vmbits & VISIBILITYMAP_ALL_FROZEN) != 0)
{
- ereport(WARNING,
- (errcode(ERRCODE_DATA_CORRUPTED),
- errmsg("page is not marked all-visible but visibility map bit is set in relation \"%s\" page %u",
- vacrel->relname, blkno)));
-
- visibilitymap_clear(vacrel->rel, blkno, vmbuffer,
- VISIBILITYMAP_VALID_BITS);
- }
-
- /*
- * It's possible for the value returned by
- * GetOldestNonRemovableTransactionId() to move backwards, so it's not
- * wrong for us to see tuples that appear to not be visible to everyone
- * yet, while PD_ALL_VISIBLE is already set. The real safe xmin value
- * never moves backwards, but GetOldestNonRemovableTransactionId() is
- * conservative and sometimes returns a value that's unnecessarily small,
- * so if we see that contradiction it just means that the tuples that we
- * think are not visible to everyone yet actually are, and the
- * PD_ALL_VISIBLE flag is correct.
- *
- * There should never be LP_DEAD items on a page with PD_ALL_VISIBLE set,
- * however.
- */
- else if (presult.lpdead_items > 0 && PageIsAllVisible(page))
- {
- ereport(WARNING,
- (errcode(ERRCODE_DATA_CORRUPTED),
- errmsg("page containing LP_DEAD items is marked as all-visible in relation \"%s\" page %u",
- vacrel->relname, blkno)));
-
- PageClearAllVisible(page);
- MarkBufferDirty(buf);
- visibilitymap_clear(vacrel->rel, blkno, vmbuffer,
- VISIBILITYMAP_VALID_BITS);
- }
-
- /*
- * If the all-visible page is all-frozen but not marked as such yet, mark
- * it as all-frozen.
- */
- else if (all_visible_according_to_vm && presult.all_frozen &&
- !VM_ALL_FROZEN(vacrel->rel, blkno, &vmbuffer))
- {
- uint8 old_vmbits;
-
- /*
- * Avoid relying on all_visible_according_to_vm as a proxy for the
- * page-level PD_ALL_VISIBLE bit being set, since it might have become
- * stale -- even when all_visible is set
- */
- if (!PageIsAllVisible(page))
- {
- PageSetAllVisible(page);
- MarkBufferDirty(buf);
- }
-
- /*
- * Set the page all-frozen (and all-visible) in the VM.
- *
- * We can pass InvalidTransactionId as our cutoff_xid, since a
- * snapshotConflictHorizon sufficient to make everything safe for REDO
- * was logged when the page's tuples were frozen.
- */
- Assert(!TransactionIdIsValid(presult.vm_conflict_horizon));
- old_vmbits = visibilitymap_set(vacrel->rel, blkno, buf,
- InvalidXLogRecPtr,
- vmbuffer, InvalidTransactionId,
- VISIBILITYMAP_ALL_VISIBLE |
- VISIBILITYMAP_ALL_FROZEN);
-
- /*
- * The page was likely already set all-visible in the VM. However,
- * there is a small chance that it was modified sometime between
- * setting all_visible_according_to_vm and checking the visibility
- * during pruning. Check the return value of old_vmbits anyway to
- * ensure the visibility map counters used for logging are accurate.
- */
- if ((old_vmbits & VISIBILITYMAP_ALL_VISIBLE) == 0)
- {
- vacrel->vm_new_visible_pages++;
- vacrel->vm_new_visible_frozen_pages++;
- *vm_page_frozen = true;
- }
-
- /*
- * We already checked that the page was not set all-frozen in the VM
- * above, so we don't need to test the value of old_vmbits.
- */
- else
- {
- vacrel->vm_new_frozen_pages++;
- *vm_page_frozen = true;
- }
+ Assert((presult.new_vmbits & VISIBILITYMAP_ALL_VISIBLE) != 0);
+ vacrel->vm_new_frozen_pages++;
+ *vm_page_frozen = true;
}
return presult.ndeleted;
@@ -2956,6 +2782,7 @@ lazy_vacuum_heap_page(LVRelState *vacrel, BlockNumber blkno, Buffer buffer,
vmflags,
conflict_xid,
false, /* no cleanup lock required */
+ (vmflags & VISIBILITYMAP_VALID_BITS) != 0,
PRUNE_VACUUM_CLEANUP,
NULL, 0, /* frozen */
NULL, 0, /* redirected */
@@ -3643,7 +3470,7 @@ dead_items_cleanup(LVRelState *vacrel)
* that expect no LP_DEAD on the page. Currently assert-only, but there is no
* reason not to use it outside of asserts.
*/
-static bool
+bool
heap_page_is_all_visible(Relation rel, Buffer buf,
TransactionId OldestXmin,
bool *all_frozen,
diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h
index b0b6d3552a6..1471940b4a4 100644
--- a/src/include/access/heapam.h
+++ b/src/include/access/heapam.h
@@ -42,6 +42,7 @@
/* "options" flag bits for heap_page_prune_and_freeze */
#define HEAP_PAGE_PRUNE_MARK_UNUSED_NOW (1 << 0)
#define HEAP_PAGE_PRUNE_FREEZE (1 << 1)
+#define HEAP_PAGE_PRUNE_UPDATE_VIS (1 << 2)
typedef struct BulkInsertStateData *BulkInsertState;
typedef struct GlobalVisState GlobalVisState;
@@ -238,6 +239,16 @@ typedef struct PruneFreezeParams
Relation relation; /* relation containing buffer to be pruned */
Buffer buffer; /* buffer to be pruned */
+ /*
+ *
+ * vmbuffer is the buffer that must already contain contain the required
+ * block of the visibility map if we are to update it. blk_known_av is the
+ * visibility status of the heap block as of the last call to
+ * find_next_unskippable_block().
+ */
+ Buffer vmbuffer;
+ bool blk_known_av;
+
/*
* The reason pruning was performed. It is used to set the WAL record
* opcode which is used for debugging and analysis purposes.
@@ -250,8 +261,9 @@ typedef struct PruneFreezeParams
* MARK_UNUSED_NOW indicates that dead items can be set LP_UNUSED during
* pruning.
*
- * FREEZE indicates that we will also freeze tuples, and will return
- * 'all_visible', 'all_frozen' flags to the caller.
+ * FREEZE indicates that we will also freeze tuples
+ *
+ * UPDATE_VIS indicates that we will set the page's status in the VM.
*/
int options;
@@ -284,19 +296,15 @@ typedef struct PruneFreezeResult
int recently_dead_tuples;
/*
- * all_visible and all_frozen indicate if the all-visible and all-frozen
- * bits in the visibility map can be set for this page, after pruning.
- *
- * vm_conflict_horizon is the newest xmin of live tuples on the page. The
- * caller can use it as the conflict horizon when setting the VM bits. It
- * is only valid if we froze some tuples (nfrozen > 0), and all_frozen is
- * true.
+ * old_vmbits are the state of the all-visible and all-frozen bits in the
+ * visibility map before updating it during phase I of vacuuming.
+ * new_vmbits are the state of those bits after phase I of vacuuming.
*
- * These are only set if the HEAP_PRUNE_FREEZE option is set.
+ * These are only set if the HEAP_PAGE_PRUNE_UPDATE_VIS option is set and
+ * we have attempted to update the VM.
*/
- bool all_visible;
- bool all_frozen;
- TransactionId vm_conflict_horizon;
+ uint8 new_vmbits;
+ uint8 old_vmbits;
/*
* Whether or not the page makes rel truncation unsafe. This is set to
@@ -423,6 +431,7 @@ extern void log_heap_prune_and_freeze(Relation relation, Buffer buffer,
Buffer vmbuffer, uint8 vmflags,
TransactionId conflict_xid,
bool cleanup_lock,
+ bool set_pd_all_vis,
PruneReason reason,
HeapTupleFreeze *frozen, int nfrozen,
OffsetNumber *redirected, int nredirected,
@@ -433,6 +442,14 @@ extern void log_heap_prune_and_freeze(Relation relation, Buffer buffer,
extern void heap_vacuum_rel(Relation rel,
const VacuumParams params, BufferAccessStrategy bstrategy);
+#ifdef USE_ASSERT_CHECKING
+extern bool heap_page_is_all_visible(Relation rel, Buffer buf,
+ TransactionId OldestXmin,
+ bool *all_frozen,
+ TransactionId *visibility_cutoff_xid,
+ OffsetNumber *logging_offnum);
+#endif
+
/* in heap/heapam_visibility.c */
extern bool HeapTupleSatisfiesVisibility(HeapTuple htup, Snapshot snapshot,
Buffer buffer);
--
2.43.0
[text/x-patch] v19-0005-Eliminate-XLOG_HEAP2_VISIBLE-from-empty-page-vac.patch (2.5K, 6-v19-0005-Eliminate-XLOG_HEAP2_VISIBLE-from-empty-page-vac.patch)
download | inline diff:
From 90ef5b185e4940f8b6eab291460fe7115d0e7080 Mon Sep 17 00:00:00 2001
From: Melanie Plageman <[email protected]>
Date: Sat, 27 Sep 2025 11:55:21 -0400
Subject: [PATCH v19 05/12] Eliminate XLOG_HEAP2_VISIBLE from empty-page vacuum
As part of removing XLOG_HEAP2_VISIBLE records, phase I of VACUUM now
marks empty pages all-visible in a XLOG_HEAP2_PRUNE_VACUUM_SCAN record.
Author: Melanie Plageman <[email protected]>
Reviewed-by: Robert Haas <[email protected]>
---
src/backend/access/heap/vacuumlazy.c | 36 +++++++++++++++++++++++-----
1 file changed, 30 insertions(+), 6 deletions(-)
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index 60529fcf9d7..8c402b5b1d4 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -1879,9 +1879,12 @@ lazy_scan_new_or_empty(LVRelState *vacrel, Buffer buf, BlockNumber blkno,
*/
if (!PageIsAllVisible(page))
{
+ /* Lock vmbuffer before entering critical section */
+ LockBuffer(vmbuffer, BUFFER_LOCK_EXCLUSIVE);
+
START_CRIT_SECTION();
- /* mark buffer dirty before writing a WAL record */
+ /* Mark buffer dirty before writing any WAL records */
MarkBufferDirty(buf);
/*
@@ -1898,13 +1901,34 @@ lazy_scan_new_or_empty(LVRelState *vacrel, Buffer buf, BlockNumber blkno,
log_newpage_buffer(buf, true);
PageSetAllVisible(page);
- visibilitymap_set(vacrel->rel, blkno, buf,
- InvalidXLogRecPtr,
- vmbuffer, InvalidTransactionId,
- VISIBILITYMAP_ALL_VISIBLE |
- VISIBILITYMAP_ALL_FROZEN);
+ visibilitymap_set_vmbits(blkno,
+ vmbuffer,
+ VISIBILITYMAP_ALL_VISIBLE |
+ VISIBILITYMAP_ALL_FROZEN,
+ vacrel->rel->rd_locator);
+
+ /*
+ * Emit WAL for setting PD_ALL_VISIBLE on the heap page and
+ * setting the VM.
+ */
+ if (RelationNeedsWAL(vacrel->rel))
+ log_heap_prune_and_freeze(vacrel->rel, buf,
+ vmbuffer,
+ VISIBILITYMAP_ALL_VISIBLE |
+ VISIBILITYMAP_ALL_FROZEN,
+ InvalidTransactionId, /* conflict xid */
+ false, /* cleanup lock */
+ true, /* set_pd_all_vis */
+ PRUNE_VACUUM_SCAN, /* reason */
+ NULL, 0,
+ NULL, 0,
+ NULL, 0,
+ NULL, 0);
+
END_CRIT_SECTION();
+ LockBuffer(vmbuffer, BUFFER_LOCK_UNLOCK);
+
/* Count the newly all-frozen pages for logging */
vacrel->vm_new_visible_pages++;
vacrel->vm_new_visible_frozen_pages++;
--
2.43.0
[text/x-patch] v19-0006-Remove-XLOG_HEAP2_VISIBLE-entirely.patch (26.2K, 7-v19-0006-Remove-XLOG_HEAP2_VISIBLE-entirely.patch)
download | inline diff:
From 25216d74c5ded740fb5b52beb74877c7a701c3b0 Mon Sep 17 00:00:00 2001
From: Melanie Plageman <[email protected]>
Date: Sat, 27 Sep 2025 11:55:36 -0400
Subject: [PATCH v19 06/12] Remove XLOG_HEAP2_VISIBLE entirely
As no remaining users emit XLOG_HEAP2_VISIBLE records.
This includes deleting the xl_heap_visible struct and all functions
responsible for emitting or replaying XLOG_HEAP2_VISIBLE records.
Author: Melanie Plageman <[email protected]>
Reviewed-by: Andrey Borodin <[email protected]>
---
src/backend/access/common/bufmask.c | 4 +-
src/backend/access/heap/heapam.c | 54 +-------
src/backend/access/heap/heapam_xlog.c | 155 ++---------------------
src/backend/access/heap/pruneheap.c | 18 ++-
src/backend/access/heap/vacuumlazy.c | 16 +--
src/backend/access/heap/visibilitymap.c | 111 +---------------
src/backend/access/rmgrdesc/heapdesc.c | 10 --
src/backend/replication/logical/decode.c | 1 -
src/backend/storage/ipc/standby.c | 12 +-
src/include/access/heapam_xlog.h | 28 +---
src/include/access/visibilitymap.h | 13 +-
src/include/access/visibilitymapdefs.h | 9 --
src/tools/pgindent/typedefs.list | 1 -
13 files changed, 54 insertions(+), 378 deletions(-)
diff --git a/src/backend/access/common/bufmask.c b/src/backend/access/common/bufmask.c
index bb260cffa68..5f07f179415 100644
--- a/src/backend/access/common/bufmask.c
+++ b/src/backend/access/common/bufmask.c
@@ -56,8 +56,8 @@ mask_page_hint_bits(Page page)
/*
* During replay, if the page LSN has advanced past our XLOG record's LSN,
- * we don't mark the page all-visible. See heap_xlog_visible() for
- * details.
+ * we don't mark the page all-visible. See heap_xlog_prune_and_freeze()
+ * for more details.
*/
PageClearAllVisible(page);
}
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 36fee9c994e..a0c5923a563 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -2524,11 +2524,11 @@ heap_multi_insert(Relation relation, TupleTableSlot **slots, int ntuples,
else if (all_frozen_set)
{
PageSetAllVisible(page);
- visibilitymap_set_vmbits(BufferGetBlockNumber(buffer),
- vmbuffer,
- VISIBILITYMAP_ALL_VISIBLE |
- VISIBILITYMAP_ALL_FROZEN,
- relation->rd_locator);
+ visibilitymap_set(BufferGetBlockNumber(buffer),
+ vmbuffer,
+ VISIBILITYMAP_ALL_VISIBLE |
+ VISIBILITYMAP_ALL_FROZEN,
+ relation->rd_locator);
}
/*
@@ -8797,50 +8797,6 @@ bottomup_sort_and_shrink(TM_IndexDeleteOp *delstate)
return nblocksfavorable;
}
-/*
- * Perform XLogInsert for a heap-visible operation. 'block' is the block
- * being marked all-visible, and vm_buffer is the buffer containing the
- * corresponding visibility map block. Both should have already been modified
- * and dirtied.
- *
- * snapshotConflictHorizon comes from the largest xmin on the page being
- * marked all-visible. REDO routine uses it to generate recovery conflicts.
- *
- * If checksums or wal_log_hints are enabled, we may also generate a full-page
- * image of heap_buffer. Otherwise, we optimize away the FPI (by specifying
- * REGBUF_NO_IMAGE for the heap buffer), in which case the caller should *not*
- * update the heap page's LSN.
- */
-XLogRecPtr
-log_heap_visible(Relation rel, Buffer heap_buffer, Buffer vm_buffer,
- TransactionId snapshotConflictHorizon, uint8 vmflags)
-{
- xl_heap_visible xlrec;
- XLogRecPtr recptr;
- uint8 flags;
-
- Assert(BufferIsValid(heap_buffer));
- Assert(BufferIsValid(vm_buffer));
-
- xlrec.snapshotConflictHorizon = snapshotConflictHorizon;
- xlrec.flags = vmflags;
- if (RelationIsAccessibleInLogicalDecoding(rel))
- xlrec.flags |= VISIBILITYMAP_XLOG_CATALOG_REL;
- XLogBeginInsert();
- XLogRegisterData(&xlrec, SizeOfHeapVisible);
-
- XLogRegisterBuffer(0, vm_buffer, 0);
-
- flags = REGBUF_STANDARD;
- if (!XLogHintBitIsNeeded())
- flags |= REGBUF_NO_IMAGE;
- XLogRegisterBuffer(1, heap_buffer, flags);
-
- recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_VISIBLE);
-
- return recptr;
-}
-
/*
* Perform XLogInsert for a heap-update operation. Caller must already
* have modified the buffer(s) and marked them dirty.
diff --git a/src/backend/access/heap/heapam_xlog.c b/src/backend/access/heap/heapam_xlog.c
index 2af724451c3..5ab46e8bf8f 100644
--- a/src/backend/access/heap/heapam_xlog.c
+++ b/src/backend/access/heap/heapam_xlog.c
@@ -251,7 +251,7 @@ heap_xlog_prune_freeze(XLogReaderState *record)
if (PageIsNew(vmpage))
PageInit(vmpage, BLCKSZ, 0);
- visibilitymap_set_vmbits(blkno, vmbuffer, vmflags, rlocator);
+ visibilitymap_set(blkno, vmbuffer, vmflags, rlocator);
Assert(BufferIsDirty(vmbuffer));
PageSetLSN(vmpage, lsn);
@@ -264,142 +264,6 @@ heap_xlog_prune_freeze(XLogReaderState *record)
XLogRecordPageWithFreeSpace(rlocator, blkno, freespace);
}
-/*
- * Replay XLOG_HEAP2_VISIBLE records.
- *
- * The critical integrity requirement here is that we must never end up with
- * a situation where the visibility map bit is set, and the page-level
- * PD_ALL_VISIBLE bit is clear. If that were to occur, then a subsequent
- * page modification would fail to clear the visibility map bit.
- */
-static void
-heap_xlog_visible(XLogReaderState *record)
-{
- XLogRecPtr lsn = record->EndRecPtr;
- xl_heap_visible *xlrec = (xl_heap_visible *) XLogRecGetData(record);
- Buffer vmbuffer = InvalidBuffer;
- Buffer buffer;
- Page page;
- RelFileLocator rlocator;
- BlockNumber blkno;
- XLogRedoAction action;
-
- Assert((xlrec->flags & VISIBILITYMAP_XLOG_VALID_BITS) == xlrec->flags);
-
- XLogRecGetBlockTag(record, 1, &rlocator, NULL, &blkno);
-
- /*
- * If there are any Hot Standby transactions running that have an xmin
- * horizon old enough that this page isn't all-visible for them, they
- * might incorrectly decide that an index-only scan can skip a heap fetch.
- *
- * NB: It might be better to throw some kind of "soft" conflict here that
- * forces any index-only scan that is in flight to perform heap fetches,
- * rather than killing the transaction outright.
- */
- if (InHotStandby)
- ResolveRecoveryConflictWithSnapshot(xlrec->snapshotConflictHorizon,
- xlrec->flags & VISIBILITYMAP_XLOG_CATALOG_REL,
- rlocator);
-
- /*
- * Read the heap page, if it still exists. If the heap file has dropped or
- * truncated later in recovery, we don't need to update the page, but we'd
- * better still update the visibility map.
- */
- action = XLogReadBufferForRedo(record, 1, &buffer);
- if (action == BLK_NEEDS_REDO)
- {
- /*
- * We don't bump the LSN of the heap page when setting the visibility
- * map bit (unless checksums or wal_hint_bits is enabled, in which
- * case we must). This exposes us to torn page hazards, but since
- * we're not inspecting the existing page contents in any way, we
- * don't care.
- */
- page = BufferGetPage(buffer);
-
- PageSetAllVisible(page);
-
- if (XLogHintBitIsNeeded())
- PageSetLSN(page, lsn);
-
- MarkBufferDirty(buffer);
- }
- else if (action == BLK_RESTORED)
- {
- /*
- * If heap block was backed up, we already restored it and there's
- * nothing more to do. (This can only happen with checksums or
- * wal_log_hints enabled.)
- */
- }
-
- if (BufferIsValid(buffer))
- {
- Size space = PageGetFreeSpace(BufferGetPage(buffer));
-
- UnlockReleaseBuffer(buffer);
-
- /*
- * Since FSM is not WAL-logged and only updated heuristically, it
- * easily becomes stale in standbys. If the standby is later promoted
- * and runs VACUUM, it will skip updating individual free space
- * figures for pages that became all-visible (or all-frozen, depending
- * on the vacuum mode,) which is troublesome when FreeSpaceMapVacuum
- * propagates too optimistic free space values to upper FSM layers;
- * later inserters try to use such pages only to find out that they
- * are unusable. This can cause long stalls when there are many such
- * pages.
- *
- * Forestall those problems by updating FSM's idea about a page that
- * is becoming all-visible or all-frozen.
- *
- * Do this regardless of a full-page image being applied, since the
- * FSM data is not in the page anyway.
- */
- if (xlrec->flags & VISIBILITYMAP_VALID_BITS)
- XLogRecordPageWithFreeSpace(rlocator, blkno, space);
- }
-
- /*
- * Even if we skipped the heap page update due to the LSN interlock, it's
- * still safe to update the visibility map. Any WAL record that clears
- * the visibility map bit does so before checking the page LSN, so any
- * bits that need to be cleared will still be cleared.
- */
- if (XLogReadBufferForRedoExtended(record, 0, RBM_ZERO_ON_ERROR, false,
- &vmbuffer) == BLK_NEEDS_REDO)
- {
- Page vmpage = BufferGetPage(vmbuffer);
- Relation reln;
- uint8 vmbits;
-
- /* initialize the page if it was read as zeros */
- if (PageIsNew(vmpage))
- PageInit(vmpage, BLCKSZ, 0);
-
- /* remove VISIBILITYMAP_XLOG_* */
- vmbits = xlrec->flags & VISIBILITYMAP_VALID_BITS;
-
- /*
- * XLogReadBufferForRedoExtended locked the buffer. But
- * visibilitymap_set will handle locking itself.
- */
- LockBuffer(vmbuffer, BUFFER_LOCK_UNLOCK);
-
- reln = CreateFakeRelcacheEntry(rlocator);
-
- visibilitymap_set(reln, blkno, InvalidBuffer, lsn, vmbuffer,
- xlrec->snapshotConflictHorizon, vmbits);
-
- ReleaseBuffer(vmbuffer);
- FreeFakeRelcacheEntry(reln);
- }
- else if (BufferIsValid(vmbuffer))
- UnlockReleaseBuffer(vmbuffer);
-}
-
/*
* 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.
@@ -777,8 +641,8 @@ heap_xlog_multi_insert(XLogReaderState *record)
*
* During recovery, however, no concurrent writers exist. Therefore,
* updating the VM without holding the heap page lock is safe enough. This
- * same approach is taken when replaying xl_heap_visible records (see
- * heap_xlog_visible()).
+ * same approach is taken when replaying XLOG_HEAP2_PRUNE* records (see
+ * heap_xlog_prune_and_freeze()).
*/
if ((xlrec->flags & XLH_INSERT_ALL_FROZEN_SET) &&
XLogReadBufferForRedoExtended(record, 1, RBM_ZERO_ON_ERROR, false,
@@ -790,11 +654,11 @@ heap_xlog_multi_insert(XLogReaderState *record)
if (PageIsNew(vmpage))
PageInit(vmpage, BLCKSZ, 0);
- visibilitymap_set_vmbits(blkno,
- vmbuffer,
- VISIBILITYMAP_ALL_VISIBLE |
- VISIBILITYMAP_ALL_FROZEN,
- rlocator);
+ visibilitymap_set(blkno,
+ vmbuffer,
+ VISIBILITYMAP_ALL_VISIBLE |
+ VISIBILITYMAP_ALL_FROZEN,
+ rlocator);
Assert(BufferIsDirty(vmbuffer));
PageSetLSN(vmpage, lsn);
@@ -1375,9 +1239,6 @@ heap2_redo(XLogReaderState *record)
case XLOG_HEAP2_PRUNE_VACUUM_CLEANUP:
heap_xlog_prune_freeze(record);
break;
- case XLOG_HEAP2_VISIBLE:
- heap_xlog_visible(record);
- break;
case XLOG_HEAP2_MULTI_INSERT:
heap_xlog_multi_insert(record);
break;
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index 8dafbd344d8..14690cd62ae 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -1031,9 +1031,9 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
{
Assert(PageIsAllVisible(page));
- old_vmbits = visibilitymap_set_vmbits(blockno,
- vmbuffer, new_vmbits,
- params->relation->rd_locator);
+ old_vmbits = visibilitymap_set(blockno,
+ vmbuffer, new_vmbits,
+ params->relation->rd_locator);
if (old_vmbits == new_vmbits)
{
LockBuffer(vmbuffer, BUFFER_LOCK_UNLOCK);
@@ -2309,14 +2309,18 @@ get_conflict_xid(bool do_prune, bool do_freeze, bool do_set_vm,
*
* This is used for several different page maintenance operations:
*
- * - Page pruning, in VACUUM's 1st pass or on access: Some items are
+ * - Page pruning, in vacuum phase I or on-access: Some items are
* redirected, some marked dead, and some removed altogether.
*
- * - Freezing: Items are marked as 'frozen'.
+ * - Freezing: During vacuum phase I, items are marked as 'frozen'
*
- * - Vacuum, 2nd pass: Items that are already LP_DEAD are marked as unused.
+ * - Reaping: During vacuum phase III, items that are already LP_DEAD are
+ * marked as unused.
*
- * They have enough commonalities that we use a single WAL record for them
+ * - VM updates: After vacuum phases I and III, the heap page may be marked
+ * all-visible and all-frozen.
+ *
+ * These changes all happen together, so we use a single WAL record for them
* all.
*
* If replaying the record requires a cleanup lock, pass cleanup_lock = true.
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index 8c402b5b1d4..ff6f0d1d0af 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -1901,11 +1901,11 @@ lazy_scan_new_or_empty(LVRelState *vacrel, Buffer buf, BlockNumber blkno,
log_newpage_buffer(buf, true);
PageSetAllVisible(page);
- visibilitymap_set_vmbits(blkno,
- vmbuffer,
- VISIBILITYMAP_ALL_VISIBLE |
- VISIBILITYMAP_ALL_FROZEN,
- vacrel->rel->rd_locator);
+ visibilitymap_set(blkno,
+ vmbuffer,
+ VISIBILITYMAP_ALL_VISIBLE |
+ VISIBILITYMAP_ALL_FROZEN,
+ vacrel->rel->rd_locator);
/*
* Emit WAL for setting PD_ALL_VISIBLE on the heap page and
@@ -2787,9 +2787,9 @@ lazy_vacuum_heap_page(LVRelState *vacrel, BlockNumber blkno, Buffer buffer,
* set PD_ALL_VISIBLE.
*/
PageSetAllVisible(page);
- visibilitymap_set_vmbits(blkno,
- vmbuffer, vmflags,
- vacrel->rel->rd_locator);
+ visibilitymap_set(blkno,
+ vmbuffer, vmflags,
+ vacrel->rel->rd_locator);
conflict_xid = visibility_cutoff_xid;
}
diff --git a/src/backend/access/heap/visibilitymap.c b/src/backend/access/heap/visibilitymap.c
index 2f5e61e2392..a75b5bb6b13 100644
--- a/src/backend/access/heap/visibilitymap.c
+++ b/src/backend/access/heap/visibilitymap.c
@@ -14,8 +14,7 @@
* visibilitymap_clear - clear bits for one page in the visibility map
* visibilitymap_pin - pin a map page for setting a bit
* visibilitymap_pin_ok - check whether correct map page is already pinned
- * visibilitymap_set - set bit(s) in a previously pinned page and log
- * visibilitymap_set_vmbits - set bit(s) in a pinned page
+ * visibilitymap_set - set bit(s) in a previously pinned page
* visibilitymap_get_status - get status of bits
* visibilitymap_count - count number of bits set in visibility map
* visibilitymap_prepare_truncate -
@@ -220,108 +219,6 @@ visibilitymap_pin_ok(BlockNumber heapBlk, Buffer vmbuf)
return BufferIsValid(vmbuf) && BufferGetBlockNumber(vmbuf) == mapBlock;
}
-/*
- * visibilitymap_set - set bit(s) on a previously pinned page
- *
- * recptr is the LSN of the XLOG record we're replaying, if we're in recovery,
- * or InvalidXLogRecPtr in normal running. The VM page LSN is advanced to the
- * one provided; in normal running, we generate a new XLOG record and set the
- * page LSN to that value (though the heap page's LSN may *not* be updated;
- * see below). cutoff_xid is the largest xmin on the page being marked
- * all-visible; it is needed for Hot Standby, and can be InvalidTransactionId
- * if the page contains no tuples. It can also be set to InvalidTransactionId
- * when a page that is already all-visible is being marked all-frozen.
- *
- * Caller is expected to set the heap page's PD_ALL_VISIBLE bit before calling
- * this function. Except in recovery, caller should also pass the heap
- * buffer. When checksums are enabled and we're not in recovery, we must add
- * the heap buffer to the WAL chain to protect it from being torn.
- *
- * You must pass a buffer containing the correct map page to this function.
- * Call visibilitymap_pin first to pin the right one. This function doesn't do
- * any I/O.
- *
- * Returns the state of the page's VM bits before setting flags.
- */
-uint8
-visibilitymap_set(Relation rel, BlockNumber heapBlk, Buffer heapBuf,
- XLogRecPtr recptr, Buffer vmBuf, TransactionId cutoff_xid,
- uint8 flags)
-{
- BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
- uint32 mapByte = HEAPBLK_TO_MAPBYTE(heapBlk);
- uint8 mapOffset = HEAPBLK_TO_OFFSET(heapBlk);
- Page page;
- uint8 *map;
- uint8 status;
-
-#ifdef TRACE_VISIBILITYMAP
- elog(DEBUG1, "vm_set flags 0x%02X for %s %d",
- flags, RelationGetRelationName(rel), heapBlk);
-#endif
-
- Assert(InRecovery || XLogRecPtrIsInvalid(recptr));
- Assert(InRecovery || PageIsAllVisible(BufferGetPage(heapBuf)));
- Assert((flags & VISIBILITYMAP_VALID_BITS) == flags);
-
- /* Must never set all_frozen bit without also setting all_visible bit */
- Assert(flags != VISIBILITYMAP_ALL_FROZEN);
-
- /* Check that we have the right heap page pinned, if present */
- if (BufferIsValid(heapBuf) && BufferGetBlockNumber(heapBuf) != heapBlk)
- elog(ERROR, "wrong heap buffer passed to visibilitymap_set");
-
- Assert(!BufferIsValid(heapBuf) ||
- BufferIsLockedByMeInMode(heapBuf, BUFFER_LOCK_EXCLUSIVE));
-
- /* Check that we have the right VM page pinned */
- if (!BufferIsValid(vmBuf) || BufferGetBlockNumber(vmBuf) != mapBlock)
- elog(ERROR, "wrong VM buffer passed to visibilitymap_set");
-
- page = BufferGetPage(vmBuf);
- map = (uint8 *) PageGetContents(page);
- LockBuffer(vmBuf, BUFFER_LOCK_EXCLUSIVE);
-
- status = (map[mapByte] >> mapOffset) & VISIBILITYMAP_VALID_BITS;
- if (flags != status)
- {
- START_CRIT_SECTION();
-
- map[mapByte] |= (flags << mapOffset);
- MarkBufferDirty(vmBuf);
-
- if (RelationNeedsWAL(rel))
- {
- if (XLogRecPtrIsInvalid(recptr))
- {
- Assert(!InRecovery);
- recptr = log_heap_visible(rel, heapBuf, vmBuf, cutoff_xid, flags);
-
- /*
- * If data checksums are enabled (or wal_log_hints=on), we
- * need to protect the heap page from being torn.
- *
- * If not, then we must *not* update the heap page's LSN. In
- * this case, the FPI for the heap page was omitted from the
- * WAL record inserted above, so it would be incorrect to
- * update the heap page's LSN.
- */
- if (XLogHintBitIsNeeded())
- {
- Page heapPage = BufferGetPage(heapBuf);
-
- PageSetLSN(heapPage, recptr);
- }
- }
- PageSetLSN(page, recptr);
- }
-
- END_CRIT_SECTION();
- }
-
- LockBuffer(vmBuf, BUFFER_LOCK_UNLOCK);
- return status;
-}
/*
* Set VM (visibility map) flags in the VM block in vmBuf.
@@ -344,9 +241,9 @@ visibilitymap_set(Relation rel, BlockNumber heapBlk, Buffer heapBuf,
* rlocator is used only for debugging messages.
*/
uint8
-visibilitymap_set_vmbits(BlockNumber heapBlk,
- Buffer vmBuf, uint8 flags,
- const RelFileLocator rlocator)
+visibilitymap_set(BlockNumber heapBlk,
+ Buffer vmBuf, uint8 flags,
+ const RelFileLocator rlocator)
{
BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
uint32 mapByte = HEAPBLK_TO_MAPBYTE(heapBlk);
diff --git a/src/backend/access/rmgrdesc/heapdesc.c b/src/backend/access/rmgrdesc/heapdesc.c
index ca26d1f0ed1..08461fdf593 100644
--- a/src/backend/access/rmgrdesc/heapdesc.c
+++ b/src/backend/access/rmgrdesc/heapdesc.c
@@ -349,13 +349,6 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
}
}
}
- else if (info == XLOG_HEAP2_VISIBLE)
- {
- xl_heap_visible *xlrec = (xl_heap_visible *) rec;
-
- appendStringInfo(buf, "snapshotConflictHorizon: %u, flags: 0x%02X",
- xlrec->snapshotConflictHorizon, xlrec->flags);
- }
else if (info == XLOG_HEAP2_MULTI_INSERT)
{
xl_heap_multi_insert *xlrec = (xl_heap_multi_insert *) rec;
@@ -461,9 +454,6 @@ heap2_identify(uint8 info)
case XLOG_HEAP2_PRUNE_VACUUM_CLEANUP:
id = "PRUNE_VACUUM_CLEANUP";
break;
- case XLOG_HEAP2_VISIBLE:
- id = "VISIBLE";
- break;
case XLOG_HEAP2_MULTI_INSERT:
id = "MULTI_INSERT";
break;
diff --git a/src/backend/replication/logical/decode.c b/src/backend/replication/logical/decode.c
index cc03f0706e9..2fdd4af90a8 100644
--- a/src/backend/replication/logical/decode.c
+++ b/src/backend/replication/logical/decode.c
@@ -454,7 +454,6 @@ heap2_decode(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
case XLOG_HEAP2_PRUNE_ON_ACCESS:
case XLOG_HEAP2_PRUNE_VACUUM_SCAN:
case XLOG_HEAP2_PRUNE_VACUUM_CLEANUP:
- case XLOG_HEAP2_VISIBLE:
case XLOG_HEAP2_LOCK_UPDATED:
break;
default:
diff --git a/src/backend/storage/ipc/standby.c b/src/backend/storage/ipc/standby.c
index 4222bdab078..c619643e121 100644
--- a/src/backend/storage/ipc/standby.c
+++ b/src/backend/storage/ipc/standby.c
@@ -475,12 +475,12 @@ ResolveRecoveryConflictWithSnapshot(TransactionId snapshotConflictHorizon,
* If we get passed InvalidTransactionId then we do nothing (no conflict).
*
* This can happen when replaying already-applied WAL records after a
- * standby crash or restart, or when replaying an XLOG_HEAP2_VISIBLE
- * record that marks as frozen a page which was already all-visible. It's
- * also quite common with records generated during index deletion
- * (original execution of the deletion can reason that a recovery conflict
- * which is sufficient for the deletion operation must take place before
- * replay of the deletion record itself).
+ * standby crash or restart, or when replaying a record that marks as
+ * frozen a page which was already marked all-visible in the visibility
+ * map. It's also quite common with records generated during index
+ * deletion (original execution of the deletion can reason that a recovery
+ * conflict which is sufficient for the deletion operation must take place
+ * before replay of the deletion record itself).
*/
if (!TransactionIdIsValid(snapshotConflictHorizon))
return;
diff --git a/src/include/access/heapam_xlog.h b/src/include/access/heapam_xlog.h
index 16c2b2e3c9c..e9e77bd678b 100644
--- a/src/include/access/heapam_xlog.h
+++ b/src/include/access/heapam_xlog.h
@@ -60,7 +60,6 @@
#define XLOG_HEAP2_PRUNE_ON_ACCESS 0x10
#define XLOG_HEAP2_PRUNE_VACUUM_SCAN 0x20
#define XLOG_HEAP2_PRUNE_VACUUM_CLEANUP 0x30
-#define XLOG_HEAP2_VISIBLE 0x40
#define XLOG_HEAP2_MULTI_INSERT 0x50
#define XLOG_HEAP2_LOCK_UPDATED 0x60
#define XLOG_HEAP2_NEW_CID 0x70
@@ -294,7 +293,13 @@ typedef struct xl_heap_prune
#define SizeOfHeapPrune (offsetof(xl_heap_prune, flags) + sizeof(uint16))
-/* to handle recovery conflict during logical decoding on standby */
+/*
+ * To handle recovery conflict during logical decoding on standby, we must know
+ * if the table is a catalog table. Note that in visibilitymapdefs.h
+ * VISIBLITYMAP_XLOG_CATALOG_REL is also defined as (1 << 2). xl_heap_prune
+ * records should use XLHP_IS_CATALOG_REL, not VISIBILIYTMAP_XLOG_CATALOG_REL --
+ * even if they only contain updates to the VM.
+ */
#define XLHP_IS_CATALOG_REL (1 << 1)
/*
@@ -443,20 +448,6 @@ typedef struct xl_heap_inplace
#define MinSizeOfHeapInplace (offsetof(xl_heap_inplace, nmsgs) + sizeof(int))
-/*
- * This is what we need to know about setting a visibility map bit
- *
- * Backup blk 0: visibility map buffer
- * Backup blk 1: heap buffer
- */
-typedef struct xl_heap_visible
-{
- TransactionId snapshotConflictHorizon;
- uint8 flags;
-} xl_heap_visible;
-
-#define SizeOfHeapVisible (offsetof(xl_heap_visible, flags) + sizeof(uint8))
-
typedef struct xl_heap_new_cid
{
/*
@@ -500,11 +491,6 @@ extern void heap2_desc(StringInfo buf, XLogReaderState *record);
extern const char *heap2_identify(uint8 info);
extern void heap_xlog_logical_rewrite(XLogReaderState *r);
-extern XLogRecPtr log_heap_visible(Relation rel, Buffer heap_buffer,
- Buffer vm_buffer,
- TransactionId snapshotConflictHorizon,
- uint8 vmflags);
-
/* in heapdesc.c, so it can be shared between frontend/backend code */
extern void heap_xlog_deserialize_prune_and_freeze(char *cursor, uint16 flags,
int *nplans, xlhp_freeze_plan **plans,
diff --git a/src/include/access/visibilitymap.h b/src/include/access/visibilitymap.h
index c6fa37be968..05ba6786b47 100644
--- a/src/include/access/visibilitymap.h
+++ b/src/include/access/visibilitymap.h
@@ -15,7 +15,6 @@
#define VISIBILITYMAP_H
#include "access/visibilitymapdefs.h"
-#include "access/xlogdefs.h"
#include "storage/block.h"
#include "storage/buf.h"
#include "storage/relfilelocator.h"
@@ -32,15 +31,9 @@ extern bool visibilitymap_clear(Relation rel, BlockNumber heapBlk,
extern void visibilitymap_pin(Relation rel, BlockNumber heapBlk,
Buffer *vmbuf);
extern bool visibilitymap_pin_ok(BlockNumber heapBlk, Buffer vmbuf);
-extern uint8 visibilitymap_set(Relation rel,
- BlockNumber heapBlk, Buffer heapBuf,
- XLogRecPtr recptr,
- Buffer vmBuf,
- TransactionId cutoff_xid,
- uint8 flags);
-extern uint8 visibilitymap_set_vmbits(BlockNumber heapBlk,
- Buffer vmBuf, uint8 flags,
- const RelFileLocator rlocator);
+extern uint8 visibilitymap_set(BlockNumber heapBlk,
+ Buffer vmBuf, uint8 flags,
+ const RelFileLocator rlocator);
extern uint8 visibilitymap_get_status(Relation rel, BlockNumber heapBlk, Buffer *vmbuf);
extern void visibilitymap_count(Relation rel, BlockNumber *all_visible, BlockNumber *all_frozen);
extern BlockNumber visibilitymap_prepare_truncate(Relation rel,
diff --git a/src/include/access/visibilitymapdefs.h b/src/include/access/visibilitymapdefs.h
index 5ad5c020877..e01bce4c99f 100644
--- a/src/include/access/visibilitymapdefs.h
+++ b/src/include/access/visibilitymapdefs.h
@@ -21,14 +21,5 @@
#define VISIBILITYMAP_ALL_FROZEN 0x02
#define VISIBILITYMAP_VALID_BITS 0x03 /* OR of all valid visibilitymap
* flags bits */
-/*
- * To detect recovery conflicts during logical decoding on a standby, we need
- * to know if a table is a user catalog table. For that we add an additional
- * bit into xl_heap_visible.flags, in addition to the above.
- *
- * NB: VISIBILITYMAP_XLOG_* may not be passed to visibilitymap_set().
- */
-#define VISIBILITYMAP_XLOG_CATALOG_REL 0x04
-#define VISIBILITYMAP_XLOG_VALID_BITS (VISIBILITYMAP_VALID_BITS | VISIBILITYMAP_XLOG_CATALOG_REL)
#endif /* VISIBILITYMAPDEFS_H */
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index a384171de0d..6b4a40f616c 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -4281,7 +4281,6 @@ xl_heap_prune
xl_heap_rewrite_mapping
xl_heap_truncate
xl_heap_update
-xl_heap_visible
xl_invalid_page
xl_invalid_page_key
xl_invalidations
--
2.43.0
[text/x-patch] v19-0007-Rename-GlobalVisTestIsRemovableXid-to-GlobalVisX.patch (8.2K, 8-v19-0007-Rename-GlobalVisTestIsRemovableXid-to-GlobalVisX.patch)
download | inline diff:
From 44e0d30a3672a28187e0fb1da014f05747c00d29 Mon Sep 17 00:00:00 2001
From: Melanie Plageman <[email protected]>
Date: Fri, 18 Jul 2025 16:30:04 -0400
Subject: [PATCH v19 07/12] Rename GlobalVisTestIsRemovableXid() to
GlobalVisXidVisibleToAll()
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
The function is currently only used to check whether a tuple’s xmax is
visible to all transactions (and thus removable). Upcoming changes will
also use it to test whether a tuple’s xmin is visible to all to
decide if a page can be marked all-visible in the visibility map.
The new name, GlobalVisXidVisibleToAll(), better reflects this broader
purpose.
Reviewed-by: Kirill Reshke <[email protected]>
---
src/backend/access/heap/heapam_visibility.c | 6 +++---
src/backend/access/heap/pruneheap.c | 16 ++++++++--------
src/backend/access/spgist/spgvacuum.c | 2 +-
src/backend/storage/ipc/procarray.c | 17 ++++++++---------
src/include/utils/snapmgr.h | 4 ++--
5 files changed, 22 insertions(+), 23 deletions(-)
diff --git a/src/backend/access/heap/heapam_visibility.c b/src/backend/access/heap/heapam_visibility.c
index 05f6946fe60..4ebc8abdbeb 100644
--- a/src/backend/access/heap/heapam_visibility.c
+++ b/src/backend/access/heap/heapam_visibility.c
@@ -1447,7 +1447,7 @@ HeapTupleSatisfiesNonVacuumable(HeapTuple htup, Snapshot snapshot,
{
Assert(TransactionIdIsValid(dead_after));
- if (GlobalVisTestIsRemovableXid(snapshot->vistest, dead_after))
+ if (GlobalVisXidVisibleToAll(snapshot->vistest, dead_after))
res = HEAPTUPLE_DEAD;
}
else
@@ -1512,8 +1512,8 @@ HeapTupleIsSurelyDead(HeapTuple htup, GlobalVisState *vistest)
return false;
/* Deleter committed, so tuple is dead if the XID is old enough. */
- return GlobalVisTestIsRemovableXid(vistest,
- HeapTupleHeaderGetRawXmax(tuple));
+ return GlobalVisXidVisibleToAll(vistest,
+ HeapTupleHeaderGetRawXmax(tuple));
}
/*
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index 14690cd62ae..d03b754b2cc 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -235,7 +235,7 @@ heap_page_prune_opt(Relation relation, Buffer buffer)
*/
vistest = GlobalVisTestFor(relation);
- if (!GlobalVisTestIsRemovableXid(vistest, prune_xid))
+ if (!GlobalVisXidVisibleToAll(vistest, prune_xid))
return;
/*
@@ -730,9 +730,9 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
* Determining HTSV only once for each tuple is required for correctness,
* to deal with cases where running HTSV twice could result in different
* results. For example, RECENTLY_DEAD can turn to DEAD if another
- * checked item causes GlobalVisTestIsRemovableFullXid() to update the
- * horizon, or INSERT_IN_PROGRESS can change to DEAD if the inserting
- * transaction aborts.
+ * checked item causes GlobalVisXidVisibleToAll() to update the horizon,
+ * or INSERT_IN_PROGRESS can change to DEAD if the inserting transaction
+ * aborts.
*
* It's also good for performance. Most commonly tuples within a page are
* stored at decreasing offsets (while the items are stored at increasing
@@ -1157,11 +1157,11 @@ heap_prune_satisfies_vacuum(PruneState *prstate, HeapTuple tup, Buffer buffer)
* Determine whether or not the tuple is considered dead when compared
* with the provided GlobalVisState. On-access pruning does not provide
* VacuumCutoffs. And for vacuum, even if the tuple's xmax is not older
- * than OldestXmin, GlobalVisTestIsRemovableXid() could find the row dead
- * if the GlobalVisState has been updated since the beginning of vacuuming
+ * than OldestXmin, GlobalVisXidVisibleToAll() could find the row dead if
+ * the GlobalVisState has been updated since the beginning of vacuuming
* the relation.
*/
- if (GlobalVisTestIsRemovableXid(prstate->vistest, dead_after))
+ if (GlobalVisXidVisibleToAll(prstate->vistest, dead_after))
return HEAPTUPLE_DEAD;
return res;
@@ -1618,7 +1618,7 @@ heap_prune_record_unchanged_lp_normal(Page page, PruneState *prstate, OffsetNumb
/*
* For now always use prstate->cutoffs for this test, because
* we only update 'all_visible' when freezing is requested. We
- * could use GlobalVisTestIsRemovableXid instead, if a
+ * could use GlobalVisXidVisibleToAll() instead, if a
* non-freezing caller wanted to set the VM bit.
*/
Assert(prstate->cutoffs);
diff --git a/src/backend/access/spgist/spgvacuum.c b/src/backend/access/spgist/spgvacuum.c
index 71ef2e5036f..1c0eb425ee9 100644
--- a/src/backend/access/spgist/spgvacuum.c
+++ b/src/backend/access/spgist/spgvacuum.c
@@ -536,7 +536,7 @@ vacuumRedirectAndPlaceholder(Relation index, Relation heaprel, Buffer buffer)
*/
if (dt->tupstate == SPGIST_REDIRECT &&
(!TransactionIdIsValid(dt->xid) ||
- GlobalVisTestIsRemovableXid(vistest, dt->xid)))
+ GlobalVisXidVisibleToAll(vistest, dt->xid)))
{
dt->tupstate = SPGIST_PLACEHOLDER;
Assert(opaque->nRedirection > 0);
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index 200f72c6e25..235c3b584f6 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -4181,8 +4181,7 @@ GlobalVisUpdate(void)
* See comment for GlobalVisState for details.
*/
bool
-GlobalVisTestIsRemovableFullXid(GlobalVisState *state,
- FullTransactionId fxid)
+GlobalVisFullXidVisibleToAll(GlobalVisState *state, FullTransactionId fxid)
{
/*
* If fxid is older than maybe_needed bound, it definitely is visible to
@@ -4216,14 +4215,14 @@ GlobalVisTestIsRemovableFullXid(GlobalVisState *state,
}
/*
- * Wrapper around GlobalVisTestIsRemovableFullXid() for 32bit xids.
+ * Wrapper around GlobalVisFullXidVisibleToAll() for 32bit xids.
*
* It is crucial that this only gets called for xids from a source that
* protects against xid wraparounds (e.g. from a table and thus protected by
* relfrozenxid).
*/
bool
-GlobalVisTestIsRemovableXid(GlobalVisState *state, TransactionId xid)
+GlobalVisXidVisibleToAll(GlobalVisState *state, TransactionId xid)
{
FullTransactionId fxid;
@@ -4237,12 +4236,12 @@ GlobalVisTestIsRemovableXid(GlobalVisState *state, TransactionId xid)
*/
fxid = FullXidRelativeTo(state->definitely_needed, xid);
- return GlobalVisTestIsRemovableFullXid(state, fxid);
+ return GlobalVisFullXidVisibleToAll(state, fxid);
}
/*
* Convenience wrapper around GlobalVisTestFor() and
- * GlobalVisTestIsRemovableFullXid(), see their comments.
+ * GlobalVisFullXidVisibleToAll(), see their comments.
*/
bool
GlobalVisCheckRemovableFullXid(Relation rel, FullTransactionId fxid)
@@ -4251,12 +4250,12 @@ GlobalVisCheckRemovableFullXid(Relation rel, FullTransactionId fxid)
state = GlobalVisTestFor(rel);
- return GlobalVisTestIsRemovableFullXid(state, fxid);
+ return GlobalVisFullXidVisibleToAll(state, fxid);
}
/*
* Convenience wrapper around GlobalVisTestFor() and
- * GlobalVisTestIsRemovableXid(), see their comments.
+ * GlobalVisTestIsVisibleXid(), see their comments.
*/
bool
GlobalVisCheckRemovableXid(Relation rel, TransactionId xid)
@@ -4265,7 +4264,7 @@ GlobalVisCheckRemovableXid(Relation rel, TransactionId xid)
state = GlobalVisTestFor(rel);
- return GlobalVisTestIsRemovableXid(state, xid);
+ return GlobalVisXidVisibleToAll(state, xid);
}
/*
diff --git a/src/include/utils/snapmgr.h b/src/include/utils/snapmgr.h
index 604c1f90216..a0ea2cfcea2 100644
--- a/src/include/utils/snapmgr.h
+++ b/src/include/utils/snapmgr.h
@@ -100,8 +100,8 @@ extern char *ExportSnapshot(Snapshot snapshot);
*/
typedef struct GlobalVisState GlobalVisState;
extern GlobalVisState *GlobalVisTestFor(Relation rel);
-extern bool GlobalVisTestIsRemovableXid(GlobalVisState *state, TransactionId xid);
-extern bool GlobalVisTestIsRemovableFullXid(GlobalVisState *state, FullTransactionId fxid);
+extern bool GlobalVisXidVisibleToAll(GlobalVisState *state, TransactionId xid);
+extern bool GlobalVisFullXidVisibleToAll(GlobalVisState *state, FullTransactionId fxid);
extern bool GlobalVisCheckRemovableXid(Relation rel, TransactionId xid);
extern bool GlobalVisCheckRemovableFullXid(Relation rel, FullTransactionId fxid);
--
2.43.0
[text/x-patch] v19-0008-Use-GlobalVisState-in-vacuum-to-determine-page-l.patch (10.5K, 9-v19-0008-Use-GlobalVisState-in-vacuum-to-determine-page-l.patch)
download | inline diff:
From 7e8926fc6256dc0966b0c65e4fcec0031fbd2988 Mon Sep 17 00:00:00 2001
From: Melanie Plageman <[email protected]>
Date: Tue, 29 Jul 2025 14:38:24 -0400
Subject: [PATCH v19 08/12] Use GlobalVisState in vacuum to determine page
level visibility
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
During vacuum's first and third phases, we examine tuples' visibility
to determine if we can set the page all-visible in the visibility map.
Previously, this check compared tuple xmins against a single XID chosen at
the start of vacuum (OldestXmin). We now use GlobalVisState, which also
enables future work to set the VM during on-access pruning, since ordinary
queries have access to GlobalVisState but not OldestXmin.
This also benefits vacuum directly: in some cases, GlobalVisState may
advance during a vacuum, allowing more pages to become considered
all-visible. And, in the future, we could easily add a heuristic to
update GlobalVisState more frequently during vacuums of large tables. In
the rare case that the GlobalVisState moves backward, vacuum falls back
to OldestXmin to ensure we don’t attempt to freeze a dead tuple that
wasn’t yet prunable according to the GlobalVisState.
Because comparing a transaction ID against GlobalVisState is more
expensive than comparing against a single XID, we defer this check until
after scanning all tuples on the page. If visibility_cutoff_xid was
maintained, we perform the GlobalVisState check only once per page.
This is safe because visibility_cutoff_xid records the newest xmin on
the page; if it is globally visible, then the entire page is all-visible.
This approach may result in examining more tuple xmins than before,
since with OldestXmin we could sometimes rule out the page being
all-visible earlier. However, profiling shows the additional cost is not
significant.
---
src/backend/access/heap/heapam_visibility.c | 28 ++++++++++++++++
src/backend/access/heap/pruneheap.c | 37 ++++++++++-----------
src/backend/access/heap/vacuumlazy.c | 17 +++++-----
src/include/access/heapam.h | 7 ++--
4 files changed, 57 insertions(+), 32 deletions(-)
diff --git a/src/backend/access/heap/heapam_visibility.c b/src/backend/access/heap/heapam_visibility.c
index 4ebc8abdbeb..edd529dc3c0 100644
--- a/src/backend/access/heap/heapam_visibility.c
+++ b/src/backend/access/heap/heapam_visibility.c
@@ -1189,6 +1189,34 @@ HeapTupleSatisfiesVacuum(HeapTuple htup, TransactionId OldestXmin,
return res;
}
+/*
+ * Nearly the same as HeapTupleSatisfiesVacuum, but uses a GlobalVisState to
+ * determine whether or not a tuple is HEAPTUPLE_DEAD Or
+ * HEAPTUPLE_RECENTLY_DEAD. It serves the same purpose but can be used by
+ * callers that have not calculated a single OldestXmin value.
+ */
+HTSV_Result
+HeapTupleSatisfiesVacuumGlobalVis(HeapTuple htup, GlobalVisState *vistest,
+ Buffer buffer)
+{
+ TransactionId dead_after = InvalidTransactionId;
+ HTSV_Result res;
+
+ res = HeapTupleSatisfiesVacuumHorizon(htup, buffer, &dead_after);
+
+ if (res == HEAPTUPLE_RECENTLY_DEAD)
+ {
+ Assert(TransactionIdIsValid(dead_after));
+
+ if (GlobalVisXidVisibleToAll(vistest, dead_after))
+ res = HEAPTUPLE_DEAD;
+ }
+ else
+ Assert(!TransactionIdIsValid(dead_after));
+
+ return res;
+}
+
/*
* Work horse for HeapTupleSatisfiesVacuum and similar routines.
*
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index d03b754b2cc..d3c57eedfe3 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -712,11 +712,12 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
/*
* The visibility cutoff xid is the newest xmin of live, committed tuples
- * older than OldestXmin on the page. This field is only kept up-to-date
- * if the page is all-visible. As soon as a tuple is encountered that is
- * not visible to all, this field is unmaintained. As long as it is
- * maintained, it can be used to calculate the snapshot conflict horizon
- * when updating the VM and/or freezing all the tuples on the page.
+ * on the page older than the visibility horizon represented in the
+ * GlobalVisState. This field is only kept up-to-date if the page is
+ * all-visible. As soon as a tuple is encountered that is not visible to
+ * all, this field is unmaintained. As long as it is maintained, it can be
+ * used to calculate the snapshot conflict horizon when updating the VM
+ * and/or freezing all the tuples on the page.
*/
prstate.visibility_cutoff_xid = InvalidTransactionId;
@@ -912,6 +913,16 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
prstate.ndead > 0 ||
prstate.nunused > 0;
+ /*
+ * After processing all the live tuples on the page, if the newest xmin
+ * amongst them is not visible to everyone, the page cannot be
+ * all-visible.
+ */
+ if (prstate.all_visible &&
+ TransactionIdIsNormal(prstate.visibility_cutoff_xid) &&
+ !GlobalVisXidVisibleToAll(prstate.vistest, prstate.visibility_cutoff_xid))
+ prstate.all_visible = prstate.all_frozen = false;
+
/*
* 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
@@ -1084,10 +1095,9 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
bool debug_all_frozen;
Assert(prstate.lpdead_items == 0);
- Assert(prstate.cutoffs);
if (!heap_page_is_all_visible(params->relation, buffer,
- prstate.cutoffs->OldestXmin,
+ prstate.vistest,
&debug_all_frozen,
&debug_cutoff, off_loc))
Assert(false);
@@ -1615,19 +1625,6 @@ heap_prune_record_unchanged_lp_normal(Page page, PruneState *prstate, OffsetNumb
*/
xmin = HeapTupleHeaderGetXmin(htup);
- /*
- * For now always use prstate->cutoffs for this test, because
- * we only update 'all_visible' when freezing is requested. We
- * could use GlobalVisXidVisibleToAll() instead, if a
- * non-freezing caller wanted to set the VM bit.
- */
- Assert(prstate->cutoffs);
- if (!TransactionIdPrecedes(xmin, prstate->cutoffs->OldestXmin))
- {
- prstate->all_visible = prstate->all_frozen = false;
- break;
- }
-
/* Track newest xmin on page. */
if (TransactionIdFollows(xmin, prstate->visibility_cutoff_xid) &&
TransactionIdIsNormal(xmin))
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index ff6f0d1d0af..5e3c1d50378 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -465,7 +465,7 @@ static void dead_items_reset(LVRelState *vacrel);
static void dead_items_cleanup(LVRelState *vacrel);
static bool heap_page_would_be_all_visible(Relation rel, Buffer buf,
- TransactionId OldestXmin,
+ GlobalVisState *vistest,
OffsetNumber *deadoffsets,
int ndeadoffsets,
bool *all_frozen,
@@ -2741,7 +2741,7 @@ lazy_vacuum_heap_page(LVRelState *vacrel, BlockNumber blkno, Buffer buffer,
* done outside the critical section.
*/
if (heap_page_would_be_all_visible(vacrel->rel, buffer,
- vacrel->cutoffs.OldestXmin,
+ vacrel->vistest,
deadoffsets, num_offsets,
&all_frozen, &visibility_cutoff_xid,
&vacrel->offnum))
@@ -3496,14 +3496,13 @@ dead_items_cleanup(LVRelState *vacrel)
*/
bool
heap_page_is_all_visible(Relation rel, Buffer buf,
- TransactionId OldestXmin,
+ GlobalVisState *vistest,
bool *all_frozen,
TransactionId *visibility_cutoff_xid,
OffsetNumber *logging_offnum)
{
- return heap_page_would_be_all_visible(rel, buf,
- OldestXmin,
+ return heap_page_would_be_all_visible(rel, buf, vistest,
NULL, 0,
all_frozen,
visibility_cutoff_xid,
@@ -3524,7 +3523,7 @@ heap_page_is_all_visible(Relation rel, Buffer buf,
* Returns true if the page is all-visible other than the provided
* deadoffsets and false otherwise.
*
- * OldestXmin is used to determine visibility.
+ * vistest is used to determine visibility.
*
* Output parameters:
*
@@ -3543,7 +3542,7 @@ heap_page_is_all_visible(Relation rel, Buffer buf,
*/
static bool
heap_page_would_be_all_visible(Relation rel, Buffer buf,
- TransactionId OldestXmin,
+ GlobalVisState *vistest,
OffsetNumber *deadoffsets,
int ndeadoffsets,
bool *all_frozen,
@@ -3617,7 +3616,7 @@ heap_page_would_be_all_visible(Relation rel, Buffer buf,
/* Visibility checks may do IO or allocate memory */
Assert(CritSectionCount == 0);
- switch (HeapTupleSatisfiesVacuum(&tuple, OldestXmin, buf))
+ switch (HeapTupleSatisfiesVacuumGlobalVis(&tuple, vistest, buf))
{
case HEAPTUPLE_LIVE:
{
@@ -3636,7 +3635,7 @@ heap_page_would_be_all_visible(Relation rel, Buffer buf,
* that everyone sees it as committed?
*/
xmin = HeapTupleHeaderGetXmin(tuple.t_data);
- if (!TransactionIdPrecedes(xmin, OldestXmin))
+ if (!GlobalVisXidVisibleToAll(vistest, xmin))
{
all_visible = false;
*all_frozen = false;
diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h
index 1471940b4a4..4fc6edf4261 100644
--- a/src/include/access/heapam.h
+++ b/src/include/access/heapam.h
@@ -276,8 +276,7 @@ typedef struct PruneFreezeParams
/*
* cutoffs contains the freeze cutoffs, established by VACUUM at the
* beginning of vacuuming the relation. Required if HEAP_PRUNE_FREEZE
- * option is set. cutoffs->OldestXmin is also used to determine if dead
- * tuples are HEAPTUPLE_RECENTLY_DEAD or HEAPTUPLE_DEAD.
+ * option is set.
*/
struct VacuumCutoffs *cutoffs;
} PruneFreezeParams;
@@ -444,7 +443,7 @@ extern void heap_vacuum_rel(Relation rel,
#ifdef USE_ASSERT_CHECKING
extern bool heap_page_is_all_visible(Relation rel, Buffer buf,
- TransactionId OldestXmin,
+ GlobalVisState *vistest,
bool *all_frozen,
TransactionId *visibility_cutoff_xid,
OffsetNumber *logging_offnum);
@@ -457,6 +456,8 @@ extern TM_Result HeapTupleSatisfiesUpdate(HeapTuple htup, CommandId curcid,
Buffer buffer);
extern HTSV_Result HeapTupleSatisfiesVacuum(HeapTuple htup, TransactionId OldestXmin,
Buffer buffer);
+extern HTSV_Result HeapTupleSatisfiesVacuumGlobalVis(HeapTuple htup,
+ GlobalVisState *vistest, Buffer buffer);
extern HTSV_Result HeapTupleSatisfiesVacuumHorizon(HeapTuple htup, Buffer buffer,
TransactionId *dead_after);
extern void HeapTupleSetHintBits(HeapTupleHeader tuple, Buffer buffer,
--
2.43.0
[text/x-patch] v19-0009-Unset-all_visible-sooner-if-not-freezing.patch (2.4K, 10-v19-0009-Unset-all_visible-sooner-if-not-freezing.patch)
download | inline diff:
From 675c8aa69fd456dfee011d40c913f33cd866cab6 Mon Sep 17 00:00:00 2001
From: Melanie Plageman <[email protected]>
Date: Tue, 14 Oct 2025 15:22:35 -0400
Subject: [PATCH v19 09/12] Unset all_visible sooner if not freezing
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
In the prune/freeze path, we currently delay clearing all_visible and
all_frozen in the presence of dead items to allow opportunistic
freezing.
However, if no freezing will be attempted, there’s no need to delay.
Clearing the flags earlier avoids extra bookkeeping in
heap_prune_record_unchanged_lp_normal(). This currently has no runtime
effect because all callers that consider setting the VM also prepare
freeze plans, but upcoming changes will allow on-access pruning to set
the VM without freezing. The extra bookkeeping was noticeable in a
profile of on-access VM setting.
---
src/backend/access/heap/pruneheap.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index d3c57eedfe3..7f457abf8e1 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -1483,8 +1483,11 @@ heap_prune_record_dead(PruneState *prstate, OffsetNumber offnum,
/*
* Deliberately delay unsetting all_visible until later during pruning.
- * Removable dead tuples shouldn't preclude freezing the page.
+ * Removable dead tuples shouldn't preclude freezing the page. If we won't
+ * attempt freezing, just unset all-visible now, though.
*/
+ if (!prstate->attempt_freeze)
+ prstate->all_visible = prstate->all_frozen = false;
/* Record the dead offset for vacuum */
prstate->deadoffsets[prstate->lpdead_items++] = offnum;
@@ -1739,8 +1742,11 @@ heap_prune_record_unchanged_lp_dead(Page page, PruneState *prstate, OffsetNumber
* Similarly, don't unset all_visible until later, at the end of
* heap_page_prune_and_freeze(). This will allow us to attempt to freeze
* the page after pruning. As long as we unset it before updating the
- * visibility map, this will be correct.
+ * visibility map, this will be correct. If we won't attempt freezing,
+ * though, just unset all-visible now.
*/
+ if (!prstate->attempt_freeze)
+ prstate->all_visible = prstate->all_frozen = false;
/* Record the dead offset for vacuum */
prstate->deadoffsets[prstate->lpdead_items++] = offnum;
--
2.43.0
[text/x-patch] v19-0010-Allow-on-access-pruning-to-set-pages-all-visible.patch (28.3K, 11-v19-0010-Allow-on-access-pruning-to-set-pages-all-visible.patch)
download | inline diff:
From 85792e88a836a7909a27783b1801e1da0e51399e Mon Sep 17 00:00:00 2001
From: Melanie Plageman <[email protected]>
Date: Tue, 29 Jul 2025 14:34:30 -0400
Subject: [PATCH v19 10/12] Allow on-access pruning to set pages all-visible
Many queries do not modify the underlying relation. For such queries, if
on-access pruning occurs during the scan, we can check whether the page
has become all-visible and update the visibility map accordingly.
Previously, only vacuum and COPY FREEZE marked pages as all-visible or
all-frozen.
Supporting this requires passing information about whether the relation
is modified from the executor down to the scan descriptor.
This commit implements on-access VM setting for sequential scans as well
as for the underlying heap relation in index scans and bitmap heap
scans.
Author: Melanie Plageman <[email protected]>
Reviewed-by: Kirill Reshke <[email protected]>
Discussion: https://postgr.es/m/flat/CAAKRu_ZMw6Npd_qm2KM%2BFwQ3cMOMx1Dh3VMhp8-V7SOLxdK9-g%40mail.gmail.com
---
src/backend/access/heap/heapam.c | 15 +++-
src/backend/access/heap/heapam_handler.c | 15 +++-
src/backend/access/heap/pruneheap.c | 73 +++++++++++++++----
src/backend/access/index/indexam.c | 46 ++++++++++++
src/backend/access/table/tableam.c | 39 +++++++++-
src/backend/executor/execMain.c | 4 +
src/backend/executor/execUtils.c | 2 +
src/backend/executor/nodeBitmapHeapscan.c | 7 +-
src/backend/executor/nodeIndexscan.c | 18 +++--
src/backend/executor/nodeSeqscan.c | 24 ++++--
src/include/access/genam.h | 11 +++
src/include/access/heapam.h | 24 +++++-
src/include/access/relscan.h | 6 ++
src/include/access/tableam.h | 30 +++++++-
src/include/nodes/execnodes.h | 6 ++
.../t/035_standby_logical_decoding.pl | 3 +-
16 files changed, 284 insertions(+), 39 deletions(-)
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index a0c5923a563..260f981d457 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -555,6 +555,7 @@ heap_prepare_pagescan(TableScanDesc sscan)
Buffer buffer = scan->rs_cbuf;
BlockNumber block = scan->rs_cblock;
Snapshot snapshot;
+ Buffer *vmbuffer = NULL;
Page page;
int lines;
bool all_visible;
@@ -569,7 +570,9 @@ heap_prepare_pagescan(TableScanDesc sscan)
/*
* Prune and repair fragmentation for the whole page, if possible.
*/
- heap_page_prune_opt(scan->rs_base.rs_rd, buffer);
+ if (sscan->rs_flags & SO_ALLOW_VM_SET)
+ vmbuffer = &scan->rs_vmbuffer;
+ heap_page_prune_opt(scan->rs_base.rs_rd, buffer, vmbuffer);
/*
* We must hold share lock on the buffer content while examining tuple
@@ -1246,6 +1249,7 @@ heap_beginscan(Relation relation, Snapshot snapshot,
sizeof(TBMIterateResult));
}
+ scan->rs_vmbuffer = InvalidBuffer;
return (TableScanDesc) scan;
}
@@ -1284,6 +1288,12 @@ heap_rescan(TableScanDesc sscan, ScanKey key, bool set_params,
scan->rs_cbuf = InvalidBuffer;
}
+ if (BufferIsValid(scan->rs_vmbuffer))
+ {
+ ReleaseBuffer(scan->rs_vmbuffer);
+ scan->rs_vmbuffer = InvalidBuffer;
+ }
+
/*
* SO_TYPE_BITMAPSCAN would be cleaned up here, but it does not hold any
* additional data vs a normal HeapScan
@@ -1316,6 +1326,9 @@ heap_endscan(TableScanDesc sscan)
if (BufferIsValid(scan->rs_cbuf))
ReleaseBuffer(scan->rs_cbuf);
+ if (BufferIsValid(scan->rs_vmbuffer))
+ ReleaseBuffer(scan->rs_vmbuffer);
+
/*
* Must free the read stream before freeing the BufferAccessStrategy.
*/
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index bcbac844bb6..f05b9e4968d 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -85,6 +85,7 @@ heapam_index_fetch_begin(Relation rel)
hscan->xs_base.rel = rel;
hscan->xs_cbuf = InvalidBuffer;
+ hscan->xs_vmbuffer = InvalidBuffer;
return &hscan->xs_base;
}
@@ -99,6 +100,12 @@ heapam_index_fetch_reset(IndexFetchTableData *scan)
ReleaseBuffer(hscan->xs_cbuf);
hscan->xs_cbuf = InvalidBuffer;
}
+
+ if (BufferIsValid(hscan->xs_vmbuffer))
+ {
+ ReleaseBuffer(hscan->xs_vmbuffer);
+ hscan->xs_vmbuffer = InvalidBuffer;
+ }
}
static void
@@ -138,7 +145,8 @@ heapam_index_fetch_tuple(struct IndexFetchTableData *scan,
* Prune page, but only if we weren't already on this page
*/
if (prev_buf != hscan->xs_cbuf)
- heap_page_prune_opt(hscan->xs_base.rel, hscan->xs_cbuf);
+ heap_page_prune_opt(hscan->xs_base.rel, hscan->xs_cbuf,
+ scan->modifies_base_rel ? NULL : &hscan->xs_vmbuffer);
}
/* Obtain share-lock on the buffer so we can examine visibility */
@@ -2471,6 +2479,7 @@ BitmapHeapScanNextBlock(TableScanDesc scan,
TBMIterateResult *tbmres;
OffsetNumber offsets[TBM_MAX_TUPLES_PER_PAGE];
int noffsets = -1;
+ Buffer *vmbuffer = NULL;
Assert(scan->rs_flags & SO_TYPE_BITMAPSCAN);
Assert(hscan->rs_read_stream);
@@ -2517,7 +2526,9 @@ BitmapHeapScanNextBlock(TableScanDesc scan,
/*
* Prune and repair fragmentation for the whole page, if possible.
*/
- heap_page_prune_opt(scan->rs_rd, buffer);
+ if (scan->rs_flags & SO_ALLOW_VM_SET)
+ vmbuffer = &hscan->rs_vmbuffer;
+ heap_page_prune_opt(scan->rs_rd, buffer, vmbuffer);
/*
* We must hold share lock on the buffer content while examining tuple
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index 7f457abf8e1..631eb45bc96 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -188,7 +188,9 @@ static bool heap_page_will_set_vis(Relation relation,
Buffer heap_buf,
Buffer vmbuffer,
bool blk_known_av,
- const PruneState *prstate,
+ PruneReason reason,
+ bool do_prune, bool do_freeze,
+ PruneState *prstate,
uint8 *vmflags,
bool *do_set_pd_vis);
@@ -203,9 +205,13 @@ static bool heap_page_will_set_vis(Relation relation,
* if there's not any use in pruning.
*
* Caller must have pin on the buffer, and must *not* have a lock on it.
+ *
+ * If vmbuffer is not NULL, it is okay for pruning to set the visibility map if
+ * the page is all-visible. We will take care of pinning and, if needed,
+ * reading in the page of the visibility map.
*/
void
-heap_page_prune_opt(Relation relation, Buffer buffer)
+heap_page_prune_opt(Relation relation, Buffer buffer, Buffer *vmbuffer)
{
Page page = BufferGetPage(buffer);
TransactionId prune_xid;
@@ -271,12 +277,21 @@ heap_page_prune_opt(Relation relation, Buffer buffer)
PruneFreezeParams params;
PruneFreezeResult presult;
+ params.options = 0;
+ params.vmbuffer = InvalidBuffer;
+
+ if (vmbuffer)
+ {
+ visibilitymap_pin(relation, BufferGetBlockNumber(buffer), vmbuffer);
+ params.options = HEAP_PAGE_PRUNE_UPDATE_VIS;
+ params.vmbuffer = *vmbuffer;
+ }
+
params.relation = relation;
params.buffer = buffer;
params.reason = PRUNE_ON_ACCESS;
params.vistest = vistest;
params.cutoffs = NULL;
- params.vmbuffer = InvalidBuffer;
params.blk_known_av = false;
/*
@@ -456,6 +471,9 @@ heap_page_will_freeze(Relation relation, Buffer buffer,
* have examined this page’s VM bits (e.g., VACUUM in the previous
* heap_vac_scan_next_block() call) and can pass that along.
*
+ * This should be called only after do_freeze has been decided (and do_prune
+ * has been set), as these factor into our heuristic-based decision.
+ *
* Returns true if one or both VM bits should be set, along with the desired
* flags in *vmflags. Also indicates via do_set_pd_vis whether PD_ALL_VISIBLE
* should be set on the heap page.
@@ -466,7 +484,9 @@ heap_page_will_set_vis(Relation relation,
Buffer heap_buf,
Buffer vmbuffer,
bool blk_known_av,
- const PruneState *prstate,
+ PruneReason reason,
+ bool do_prune, bool do_freeze,
+ PruneState *prstate,
uint8 *vmflags,
bool *do_set_pd_vis)
{
@@ -482,6 +502,23 @@ heap_page_will_set_vis(Relation relation,
return false;
}
+ /*
+ * If this is an on-access call and we're not actually pruning, avoid
+ * setting the visibility map if it would newly dirty the heap page or, if
+ * the page is already dirty, if doing so would require including a
+ * full-page image (FPI) of the heap page in the WAL. This situation
+ * should be rare, as on-access pruning is only attempted when
+ * pd_prune_xid is valid.
+ */
+ if (reason == PRUNE_ON_ACCESS &&
+ prstate->all_visible &&
+ !do_prune && !do_freeze &&
+ (!BufferIsDirty(heap_buf) || XLogCheckBufferNeedsBackup(heap_buf)))
+ {
+ prstate->all_visible = prstate->all_frozen = false;
+ return false;
+ }
+
if (prstate->all_visible && !PageIsAllVisible(heap_page))
*do_set_pd_vis = true;
@@ -505,6 +542,11 @@ heap_page_will_set_vis(Relation relation,
* page-level bit is clear. However, it's possible that in vacuum the bit
* got cleared after heap_vac_scan_next_block() was called, so we must
* recheck with buffer lock before concluding that the VM is corrupt.
+ *
+ * This will never trigger for on-access pruning because it couldn't have
+ * done a previous visibility map lookup and thus will always pass
+ * blk_known_av as false. A future vacuum will have to take care of fixing
+ * the corruption.
*/
else if (blk_known_av && !PageIsAllVisible(heap_page) &&
visibilitymap_get_status(relation, heap_blk, &vmbuffer) != 0)
@@ -913,6 +955,14 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
prstate.ndead > 0 ||
prstate.nunused > 0;
+ /*
+ * 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.
+ */
+ do_hint_prune = ((PageHeader) page)->pd_prune_xid != prstate.new_prune_xid ||
+ PageIsFull(page);
+
/*
* After processing all the live tuples on the page, if the newest xmin
* amongst them is not visible to everyone, the page cannot be
@@ -923,14 +973,6 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
!GlobalVisXidVisibleToAll(prstate.vistest, prstate.visibility_cutoff_xid))
prstate.all_visible = prstate.all_frozen = false;
- /*
- * 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.
- */
- do_hint_prune = ((PageHeader) page)->pd_prune_xid != prstate.new_prune_xid ||
- PageIsFull(page);
-
/*
* Decide if we want to go ahead with freezing according to the freeze
* plans we prepared, or not.
@@ -974,6 +1016,7 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
*/
do_set_vm = heap_page_will_set_vis(params->relation,
blockno, buffer, vmbuffer, params->blk_known_av,
+ params->reason, do_prune, do_freeze,
&prstate, &new_vmbits, &do_set_pd_vis);
/* We should only set the VM if PD_ALL_VISIBLE is set or will be */
@@ -2250,7 +2293,7 @@ heap_log_freeze_plan(HeapTupleFreeze *tuples, int ntuples,
/*
* Calculate the conflict horizon for the whole XLOG_HEAP2_PRUNE_VACUUM_SCAN
- * record.
+ * or XLOG_HEAP2_PRUNE_ON_ACCESS record.
*/
static TransactionId
get_conflict_xid(bool do_prune, bool do_freeze, bool do_set_vm,
@@ -2320,8 +2363,8 @@ get_conflict_xid(bool do_prune, bool do_freeze, bool do_set_vm,
* - Reaping: During vacuum phase III, items that are already LP_DEAD are
* marked as unused.
*
- * - VM updates: After vacuum phases I and III, the heap page may be marked
- * all-visible and all-frozen.
+ * - VM updates: After vacuum phases I and III and on-access, the heap page
+ * may be marked all-visible and all-frozen.
*
* These changes all happen together, so we use a single WAL record for them
* all.
diff --git a/src/backend/access/index/indexam.c b/src/backend/access/index/indexam.c
index 0492d92d23b..8d582a8eafd 100644
--- a/src/backend/access/index/indexam.c
+++ b/src/backend/access/index/indexam.c
@@ -289,6 +289,32 @@ index_beginscan(Relation heapRelation,
return scan;
}
+/*
+ * Similar to index_beginscan(), but allows the caller to indicate whether the
+ * query modifies the underlying base relation. This is used when the caller
+ * wants to attempt marking pages in the base relation as all-visible in the
+ * visibility map during on-access pruning.
+ */
+IndexScanDesc
+index_beginscan_vmset(Relation heapRelation,
+ Relation indexRelation,
+ Snapshot snapshot,
+ IndexScanInstrumentation *instrument,
+ int nkeys, int norderbys, bool modifies_base_rel)
+{
+ IndexScanDesc scan;
+
+ scan = index_beginscan(heapRelation,
+ indexRelation,
+ snapshot,
+ instrument,
+ nkeys, norderbys);
+
+ scan->xs_heapfetch->modifies_base_rel = modifies_base_rel;
+
+ return scan;
+}
+
/*
* index_beginscan_bitmap - start a scan of an index with amgetbitmap
*
@@ -620,6 +646,26 @@ index_beginscan_parallel(Relation heaprel, Relation indexrel,
return scan;
}
+/*
+ * Parallel version of index_beginscan_vmset()
+ */
+IndexScanDesc
+index_beginscan_parallel_vmset(Relation heaprel, Relation indexrel,
+ IndexScanInstrumentation *instrument,
+ int nkeys, int norderbys,
+ ParallelIndexScanDesc pscan,
+ bool modifies_base_rel)
+{
+ IndexScanDesc scan;
+
+ scan = index_beginscan_parallel(heaprel, indexrel,
+ instrument,
+ nkeys, norderbys,
+ pscan);
+ scan->xs_heapfetch->modifies_base_rel = modifies_base_rel;
+ return scan;
+}
+
/* ----------------
* index_getnext_tid - get the next TID from a scan
*
diff --git a/src/backend/access/table/tableam.c b/src/backend/access/table/tableam.c
index 5e41404937e..3e3a0f72a71 100644
--- a/src/backend/access/table/tableam.c
+++ b/src/backend/access/table/tableam.c
@@ -49,6 +49,10 @@
char *default_table_access_method = DEFAULT_TABLE_ACCESS_METHOD;
bool synchronize_seqscans = true;
+/* Helper for table_beginscan_parallel() and table_beginscan_parallel_vmset() */
+static TableScanDesc table_beginscan_parallel_common(Relation relation, ParallelTableScanDesc pscan,
+ uint32 flags);
+
/* ----------------------------------------------------------------------------
* Slot functions.
@@ -162,12 +166,14 @@ table_parallelscan_initialize(Relation rel, ParallelTableScanDesc pscan,
}
}
-TableScanDesc
-table_beginscan_parallel(Relation relation, ParallelTableScanDesc pscan)
+/*
+ * Common helper for table_beginscan_parallel() and table_beginscan_parallel_vmset()
+ */
+static TableScanDesc
+table_beginscan_parallel_common(Relation relation, ParallelTableScanDesc pscan,
+ uint32 flags)
{
Snapshot snapshot;
- uint32 flags = SO_TYPE_SEQSCAN |
- SO_ALLOW_STRAT | SO_ALLOW_SYNC | SO_ALLOW_PAGEMODE;
Assert(RelFileLocatorEquals(relation->rd_locator, pscan->phs_locator));
@@ -188,6 +194,31 @@ table_beginscan_parallel(Relation relation, ParallelTableScanDesc pscan)
pscan, flags);
}
+TableScanDesc
+table_beginscan_parallel(Relation relation, ParallelTableScanDesc pscan)
+{
+ uint32 flags = SO_TYPE_SEQSCAN |
+ SO_ALLOW_STRAT | SO_ALLOW_SYNC | SO_ALLOW_PAGEMODE;
+
+ return table_beginscan_parallel_common(relation, pscan, flags);
+}
+
+/*
+ * Parallel version of table_beginscan_vmset()
+ */
+TableScanDesc
+table_beginscan_parallel_vmset(Relation relation, ParallelTableScanDesc pscan,
+ bool modifies_rel)
+{
+ uint32 flags = SO_TYPE_SEQSCAN |
+ SO_ALLOW_STRAT | SO_ALLOW_SYNC | SO_ALLOW_PAGEMODE;
+
+ if (!modifies_rel)
+ flags |= SO_ALLOW_VM_SET;
+
+ return table_beginscan_parallel_common(relation, pscan, flags);
+}
+
/* ----------------------------------------------------------------------------
* Index scan related functions.
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 27c9eec697b..0630a5af79e 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -916,6 +916,10 @@ InitPlan(QueryDesc *queryDesc, int eflags)
break;
}
+ /* If it has a rowmark, the relation is modified */
+ estate->es_modified_relids = bms_add_member(estate->es_modified_relids,
+ rc->rti);
+
/* Check that relation is a legal target for marking */
if (relation)
CheckValidRowMarkRel(relation, rc->markType);
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index fdc65c2b42b..28a06dcd244 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -893,6 +893,8 @@ ExecInitResultRelation(EState *estate, ResultRelInfo *resultRelInfo,
estate->es_result_relations = (ResultRelInfo **)
palloc0(estate->es_range_table_size * sizeof(ResultRelInfo *));
estate->es_result_relations[rti - 1] = resultRelInfo;
+ estate->es_modified_relids = bms_add_member(estate->es_modified_relids,
+ rti);
/*
* Saving in the list allows to avoid needlessly traversing the whole
diff --git a/src/backend/executor/nodeBitmapHeapscan.c b/src/backend/executor/nodeBitmapHeapscan.c
index bf24f3d7fe0..af6db9f7919 100644
--- a/src/backend/executor/nodeBitmapHeapscan.c
+++ b/src/backend/executor/nodeBitmapHeapscan.c
@@ -105,11 +105,16 @@ BitmapTableScanSetup(BitmapHeapScanState *node)
*/
if (!node->ss.ss_currentScanDesc)
{
+ bool modifies_rel =
+ bms_is_member(((Scan *) node->ss.ps.plan)->scanrelid,
+ node->ss.ps.state->es_modified_relids);
+
node->ss.ss_currentScanDesc =
table_beginscan_bm(node->ss.ss_currentRelation,
node->ss.ps.state->es_snapshot,
0,
- NULL);
+ NULL,
+ modifies_rel);
}
node->ss.ss_currentScanDesc->st.rs_tbmiterator = tbmiterator;
diff --git a/src/backend/executor/nodeIndexscan.c b/src/backend/executor/nodeIndexscan.c
index f36929deec3..cbd1ecaa15f 100644
--- a/src/backend/executor/nodeIndexscan.c
+++ b/src/backend/executor/nodeIndexscan.c
@@ -102,16 +102,22 @@ IndexNext(IndexScanState *node)
if (scandesc == NULL)
{
+
+ bool modifies_base_rel =
+ bms_is_member(((Scan *) node->ss.ps.plan)->scanrelid,
+ estate->es_modified_relids);
+
/*
* We reach here if the index scan is not parallel, or if we're
* serially executing an index scan that was planned to be parallel.
*/
- scandesc = index_beginscan(node->ss.ss_currentRelation,
- node->iss_RelationDesc,
- estate->es_snapshot,
- &node->iss_Instrument,
- node->iss_NumScanKeys,
- node->iss_NumOrderByKeys);
+ scandesc = index_beginscan_vmset(node->ss.ss_currentRelation,
+ node->iss_RelationDesc,
+ estate->es_snapshot,
+ &node->iss_Instrument,
+ node->iss_NumScanKeys,
+ node->iss_NumOrderByKeys,
+ modifies_base_rel);
node->iss_ScanDesc = scandesc;
diff --git a/src/backend/executor/nodeSeqscan.c b/src/backend/executor/nodeSeqscan.c
index 94047d29430..fd69275c181 100644
--- a/src/backend/executor/nodeSeqscan.c
+++ b/src/backend/executor/nodeSeqscan.c
@@ -65,13 +65,18 @@ SeqNext(SeqScanState *node)
if (scandesc == NULL)
{
+ bool modifies_rel =
+ bms_is_member(((Scan *) node->ss.ps.plan)->scanrelid,
+ estate->es_modified_relids);
+
/*
* We reach here if the scan is not parallel, or if we're serially
* executing a scan that was planned to be parallel.
*/
- scandesc = table_beginscan(node->ss.ss_currentRelation,
- estate->es_snapshot,
- 0, NULL);
+ scandesc = table_beginscan_vmset(node->ss.ss_currentRelation,
+ estate->es_snapshot,
+ 0, NULL, modifies_rel);
+
node->ss.ss_currentScanDesc = scandesc;
}
@@ -366,6 +371,7 @@ ExecSeqScanInitializeDSM(SeqScanState *node,
ParallelContext *pcxt)
{
EState *estate = node->ss.ps.state;
+ bool modifies_rel;
ParallelTableScanDesc pscan;
pscan = shm_toc_allocate(pcxt->toc, node->pscan_len);
@@ -373,8 +379,11 @@ ExecSeqScanInitializeDSM(SeqScanState *node,
pscan,
estate->es_snapshot);
shm_toc_insert(pcxt->toc, node->ss.ps.plan->plan_node_id, pscan);
+ modifies_rel = bms_is_member(((Scan *) node->ss.ps.plan)->scanrelid,
+ estate->es_modified_relids);
node->ss.ss_currentScanDesc =
- table_beginscan_parallel(node->ss.ss_currentRelation, pscan);
+ table_beginscan_parallel_vmset(node->ss.ss_currentRelation, pscan,
+ modifies_rel);
}
/* ----------------------------------------------------------------
@@ -404,8 +413,13 @@ ExecSeqScanInitializeWorker(SeqScanState *node,
ParallelWorkerContext *pwcxt)
{
ParallelTableScanDesc pscan;
+ bool modifies_rel =
+ bms_is_member(((Scan *) node->ss.ps.plan)->scanrelid,
+ node->ss.ps.state->es_modified_relids);
pscan = shm_toc_lookup(pwcxt->toc, node->ss.ps.plan->plan_node_id, false);
node->ss.ss_currentScanDesc =
- table_beginscan_parallel(node->ss.ss_currentRelation, pscan);
+ table_beginscan_parallel_vmset(node->ss.ss_currentRelation,
+ pscan,
+ modifies_rel);
}
diff --git a/src/include/access/genam.h b/src/include/access/genam.h
index 9200a22bd9f..aa2112c8e04 100644
--- a/src/include/access/genam.h
+++ b/src/include/access/genam.h
@@ -178,6 +178,11 @@ extern IndexScanDesc index_beginscan(Relation heapRelation,
Snapshot snapshot,
IndexScanInstrumentation *instrument,
int nkeys, int norderbys);
+extern IndexScanDesc index_beginscan_vmset(Relation heapRelation,
+ Relation indexRelation,
+ Snapshot snapshot,
+ IndexScanInstrumentation *instrument,
+ int nkeys, int norderbys, bool modifies_heap_rel);
extern IndexScanDesc index_beginscan_bitmap(Relation indexRelation,
Snapshot snapshot,
IndexScanInstrumentation *instrument,
@@ -204,6 +209,12 @@ extern IndexScanDesc index_beginscan_parallel(Relation heaprel,
IndexScanInstrumentation *instrument,
int nkeys, int norderbys,
ParallelIndexScanDesc pscan);
+
+extern IndexScanDesc index_beginscan_parallel_vmset(Relation heaprel, Relation indexrel,
+ IndexScanInstrumentation *instrument,
+ int nkeys, int norderbys,
+ ParallelIndexScanDesc pscan,
+ bool modifies_rel);
extern ItemPointer index_getnext_tid(IndexScanDesc scan,
ScanDirection direction);
extern bool index_fetch_heap(IndexScanDesc scan, TupleTableSlot *slot);
diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h
index 4fc6edf4261..1d2cab64e9c 100644
--- a/src/include/access/heapam.h
+++ b/src/include/access/heapam.h
@@ -95,6 +95,13 @@ typedef struct HeapScanDescData
*/
ParallelBlockTableScanWorkerData *rs_parallelworkerdata;
+ /*
+ * For sequential scans and bitmap heap scans. If the relation is not
+ * being modified, on-access pruning may read in the current heap page's
+ * corresponding VM block to this buffer.
+ */
+ Buffer rs_vmbuffer;
+
/* these fields only used in page-at-a-time mode and for bitmap scans */
uint32 rs_cindex; /* current tuple's index in vistuples */
uint32 rs_ntuples; /* number of visible tuples on page */
@@ -117,8 +124,18 @@ typedef struct IndexFetchHeapData
{
IndexFetchTableData xs_base; /* AM independent part of the descriptor */
- Buffer xs_cbuf; /* current heap buffer in scan, if any */
- /* NB: if xs_cbuf is not InvalidBuffer, we hold a pin on that buffer */
+ /*
+ * Current heap buffer in scan, if any. NB: if xs_cbuf is not
+ * InvalidBuffer, we hold a pin on that buffer.
+ */
+ Buffer xs_cbuf;
+
+ /*
+ * For index scans that do not modify the underlying heap table, on-access
+ * pruning may read in the current heap page's corresponding VM block to
+ * this buffer.
+ */
+ Buffer xs_vmbuffer;
} IndexFetchHeapData;
/* Result codes for HeapTupleSatisfiesVacuum */
@@ -415,7 +432,8 @@ extern TransactionId heap_index_delete_tuples(Relation rel,
TM_IndexDeleteOp *delstate);
/* in heap/pruneheap.c */
-extern void heap_page_prune_opt(Relation relation, Buffer buffer);
+extern void heap_page_prune_opt(Relation relation, Buffer buffer,
+ Buffer *vmbuffer);
extern void heap_page_prune_and_freeze(PruneFreezeParams *params,
PruneFreezeResult *presult,
OffsetNumber *off_loc,
diff --git a/src/include/access/relscan.h b/src/include/access/relscan.h
index b5e0fb386c0..f496e0b4939 100644
--- a/src/include/access/relscan.h
+++ b/src/include/access/relscan.h
@@ -121,6 +121,12 @@ typedef struct ParallelBlockTableScanWorkerData *ParallelBlockTableScanWorker;
typedef struct IndexFetchTableData
{
Relation rel;
+
+ /*
+ * Some optimizations can only be performed if the query does not modify
+ * the underlying relation. Track that here.
+ */
+ bool modifies_base_rel;
} IndexFetchTableData;
struct IndexScanInstrumentation;
diff --git a/src/include/access/tableam.h b/src/include/access/tableam.h
index e16bf025692..f250d4e7aec 100644
--- a/src/include/access/tableam.h
+++ b/src/include/access/tableam.h
@@ -63,6 +63,8 @@ typedef enum ScanOptions
/* unregister snapshot at scan end? */
SO_TEMP_SNAPSHOT = 1 << 9,
+ /* whether or not scan should attempt to set the VM */
+ SO_ALLOW_VM_SET = 1 << 10,
} ScanOptions;
/*
@@ -882,6 +884,25 @@ table_beginscan(Relation rel, Snapshot snapshot,
return rel->rd_tableam->scan_begin(rel, snapshot, nkeys, key, NULL, flags);
}
+/*
+ * Similar to table_beginscan(), but allows the caller to indicate whether the
+ * query modifies the relation. This is used when the caller wants to attempt
+ * marking pages in the relation as all-visible in the visibility map during
+ * on-access pruning.
+ */
+static inline TableScanDesc
+table_beginscan_vmset(Relation rel, Snapshot snapshot,
+ int nkeys, struct ScanKeyData *key, bool modifies_rel)
+{
+ uint32 flags = SO_TYPE_SEQSCAN |
+ SO_ALLOW_STRAT | SO_ALLOW_SYNC | SO_ALLOW_PAGEMODE;
+
+ if (!modifies_rel)
+ flags |= SO_ALLOW_VM_SET;
+
+ return rel->rd_tableam->scan_begin(rel, snapshot, nkeys, key, NULL, flags);
+}
+
/*
* Like table_beginscan(), but for scanning catalog. It'll automatically use a
* snapshot appropriate for scanning catalog relations.
@@ -919,10 +940,13 @@ table_beginscan_strat(Relation rel, Snapshot snapshot,
*/
static inline TableScanDesc
table_beginscan_bm(Relation rel, Snapshot snapshot,
- int nkeys, ScanKeyData *key)
+ int nkeys, ScanKeyData *key, bool modifies_rel)
{
uint32 flags = SO_TYPE_BITMAPSCAN | SO_ALLOW_PAGEMODE;
+ if (!modifies_rel)
+ flags |= SO_ALLOW_VM_SET;
+
return rel->rd_tableam->scan_begin(rel, snapshot, nkeys, key,
NULL, flags);
}
@@ -1130,6 +1154,10 @@ extern void table_parallelscan_initialize(Relation rel,
extern TableScanDesc table_beginscan_parallel(Relation relation,
ParallelTableScanDesc pscan);
+extern TableScanDesc table_beginscan_parallel_vmset(Relation relation,
+ ParallelTableScanDesc pscan,
+ bool modifies_rel);
+
/*
* Restart a parallel scan. Call this in the leader process. Caller is
* responsible for making sure that all workers have finished the scan
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18ae8f0d4bb..0c3b0d60168 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -676,6 +676,12 @@ typedef struct EState
* ExecDoInitialPruning() */
const char *es_sourceText; /* Source text from QueryDesc */
+ /*
+ * RT indexes of relations modified by the query either through
+ * UPDATE/DELETE/INSERT/MERGE or SELECT FOR UPDATE
+ */
+ Bitmapset *es_modified_relids;
+
JunkFilter *es_junkFilter; /* top-level junk filter, if any */
/* If query can insert/delete tuples, the command ID to mark them with */
diff --git a/src/test/recovery/t/035_standby_logical_decoding.pl b/src/test/recovery/t/035_standby_logical_decoding.pl
index ebe2fae1789..bdd9f0a62cd 100644
--- a/src/test/recovery/t/035_standby_logical_decoding.pl
+++ b/src/test/recovery/t/035_standby_logical_decoding.pl
@@ -296,6 +296,7 @@ wal_level = 'logical'
max_replication_slots = 4
max_wal_senders = 4
autovacuum = off
+hot_standby_feedback = on
});
$node_primary->dump_info;
$node_primary->start;
@@ -748,7 +749,7 @@ check_pg_recvlogical_stderr($handle,
$logstart = -s $node_standby->logfile;
reactive_slots_change_hfs_and_wait_for_xmins('shared_row_removal_',
- 'no_conflict_', 0, 1);
+ 'no_conflict_', 1, 0);
# This should not trigger a conflict
wait_until_vacuum_can_remove(
--
2.43.0
[text/x-patch] v19-0011-Set-pd_prune_xid-on-insert.patch (6.7K, 12-v19-0011-Set-pd_prune_xid-on-insert.patch)
download | inline diff:
From e6b5d40c8c8758179ccd2ffe6e60dfc725430c12 Mon Sep 17 00:00:00 2001
From: Melanie Plageman <[email protected]>
Date: Tue, 29 Jul 2025 16:12:56 -0400
Subject: [PATCH v19 11/12] Set pd_prune_xid on insert
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Now that visibility map (VM) updates can occur during read-only queries,
it makes sense to also set the page’s pd_prune_xid hint during inserts.
This enables heap_page_prune_and_freeze() to run after a page is
filled with newly inserted tuples the first time it is read.
This change also addresses a long-standing note in heap_insert() and
heap_multi_insert(), which observed that setting pd_prune_xid would
help clean up aborted insertions sooner. Without it, such tuples might
linger until VACUUM, whereas now they can be pruned earlier.
Setting pd_prune_xid on insert can cause a page to be dirtied and
written out when it previously would not have been, affetcting the
reported number of hits in the index-killtuples isolation test. It is
unclear if this is a bug in the way hits are tracked, a faulty test
expectation, or if simply updating the test's expected output is
sufficient remediation.
---
src/backend/access/heap/heapam.c | 25 +++++++++++++------
src/backend/access/heap/heapam_xlog.c | 15 ++++++++++-
.../isolation/expected/index-killtuples.out | 6 ++---
3 files changed, 34 insertions(+), 12 deletions(-)
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 260f981d457..eea3a3d2ddc 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -2104,6 +2104,7 @@ heap_insert(Relation relation, HeapTuple tup, CommandId cid,
TransactionId xid = GetCurrentTransactionId();
HeapTuple heaptup;
Buffer buffer;
+ Page page;
Buffer vmbuffer = InvalidBuffer;
bool all_visible_cleared = false;
@@ -2163,15 +2164,19 @@ heap_insert(Relation relation, HeapTuple tup, CommandId cid,
}
/*
- * XXX Should we set PageSetPrunable on this page ?
+ * Set pd_prune_xid to trigger heap_page_prune_and_freeze() once the page
+ * is full so that we can set the page all-visible in the VM.
*
- * The inserting transaction may eventually abort thus making this tuple
- * DEAD and hence available for pruning. Though we don't want to optimize
- * for aborts, if no other tuple in this page is UPDATEd/DELETEd, the
- * aborted tuple will never be pruned until next vacuum is triggered.
+ * Setting pd_prune_xid is also handy if the inserting transaction
+ * eventually aborts making this tuple DEAD and hence available for
+ * pruning. If no other tuple in this page is UPDATEd/DELETEd, the aborted
+ * tuple would never otherwise be pruned until next vacuum is triggered.
*
- * If you do add PageSetPrunable here, add it in heap_xlog_insert too.
+ * Don't set it if we are in bootstrap mode, though.
*/
+ page = BufferGetPage(buffer);
+ if (TransactionIdIsNormal(xid))
+ PageSetPrunable(page, xid);
MarkBufferDirty(buffer);
@@ -2181,7 +2186,6 @@ heap_insert(Relation relation, HeapTuple tup, CommandId cid,
xl_heap_insert xlrec;
xl_heap_header xlhdr;
XLogRecPtr recptr;
- Page page = BufferGetPage(buffer);
uint8 info = XLOG_HEAP_INSERT;
int bufflags = 0;
@@ -2545,8 +2549,13 @@ heap_multi_insert(Relation relation, TupleTableSlot **slots, int ntuples,
}
/*
- * XXX Should we set PageSetPrunable on this page ? See heap_insert()
+ * Set pd_prune_xid. See heap_insert() for more on why we do this when
+ * inserting tuples. This only makes sense if we aren't already
+ * setting the page frozen in the VM. We also don't set it in
+ * bootstrap mode.
*/
+ if (!all_frozen_set && TransactionIdIsNormal(xid))
+ PageSetPrunable(page, xid);
MarkBufferDirty(buffer);
diff --git a/src/backend/access/heap/heapam_xlog.c b/src/backend/access/heap/heapam_xlog.c
index 5ab46e8bf8f..dac640f5c9d 100644
--- a/src/backend/access/heap/heapam_xlog.c
+++ b/src/backend/access/heap/heapam_xlog.c
@@ -462,6 +462,12 @@ heap_xlog_insert(XLogReaderState *record)
freespace = PageGetHeapFreeSpace(page); /* needed to update FSM below */
+ /*
+ * Set the page prunable to trigger on-access pruning later which may
+ * set the page all-visible in the VM.
+ */
+ PageSetPrunable(page, XLogRecGetXid(record));
+
PageSetLSN(page, lsn);
if (xlrec->flags & XLH_INSERT_ALL_VISIBLE_CLEARED)
@@ -611,9 +617,16 @@ heap_xlog_multi_insert(XLogReaderState *record)
if (xlrec->flags & XLH_INSERT_ALL_VISIBLE_CLEARED)
PageClearAllVisible(page);
- /* XLH_INSERT_ALL_FROZEN_SET implies that all tuples are visible */
+ /*
+ * XLH_INSERT_ALL_FROZEN_SET implies that all tuples are visible. If
+ * we are not setting the page frozen, then set the page's prunable
+ * hint so that we trigger on-access pruning later which may set the
+ * page all-visible in the VM.
+ */
if (xlrec->flags & XLH_INSERT_ALL_FROZEN_SET)
PageSetAllVisible(page);
+ else
+ PageSetPrunable(page, XLogRecGetXid(record));
MarkBufferDirty(buffer);
}
diff --git a/src/test/isolation/expected/index-killtuples.out b/src/test/isolation/expected/index-killtuples.out
index be7ddd756ef..b29f2434b00 100644
--- a/src/test/isolation/expected/index-killtuples.out
+++ b/src/test/isolation/expected/index-killtuples.out
@@ -54,7 +54,7 @@ step flush: SELECT FROM pg_stat_force_next_flush();
step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
new_heap_accesses
-----------------
- 1
+ 2
(1 row)
step measure: UPDATE counter SET heap_accesses = (SELECT heap_blks_read + heap_blks_hit FROM pg_statio_all_tables WHERE relname = 'kill_prior_tuple');
@@ -130,7 +130,7 @@ step flush: SELECT FROM pg_stat_force_next_flush();
step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
new_heap_accesses
-----------------
- 1
+ 2
(1 row)
step measure: UPDATE counter SET heap_accesses = (SELECT heap_blks_read + heap_blks_hit FROM pg_statio_all_tables WHERE relname = 'kill_prior_tuple');
@@ -283,7 +283,7 @@ step flush: SELECT FROM pg_stat_force_next_flush();
step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
new_heap_accesses
-----------------
- 1
+ 2
(1 row)
step measure: UPDATE counter SET heap_accesses = (SELECT heap_blks_read + heap_blks_hit FROM pg_statio_all_tables WHERE relname = 'kill_prior_tuple');
--
2.43.0
[text/x-patch] v19-0012-Split-heap_page_prune_and_freeze-into-helpers.patch (17.8K, 13-v19-0012-Split-heap_page_prune_and_freeze-into-helpers.patch)
download | inline diff:
From 1ff6d727d64771ed19e07e6d1644380e16508944 Mon Sep 17 00:00:00 2001
From: Melanie Plageman <[email protected]>
Date: Wed, 8 Oct 2025 18:45:45 -0400
Subject: [PATCH v19 12/12] Split heap_page_prune_and_freeze into helpers
ci-os-only:
---
src/backend/access/heap/pruneheap.c | 316 +++++++++++++++-------------
1 file changed, 170 insertions(+), 146 deletions(-)
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index 631eb45bc96..e18ec37fdf5 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -590,82 +590,20 @@ heap_page_will_set_vis(Relation relation,
return do_set_vm;
}
-/*
- * Prune and repair fragmentation and potentially freeze tuples on the
- * specified page. If the page's visibility status has changed, update it in
- * the VM.
- *
- * Caller must have pin and buffer cleanup lock on the page. Note that we
- * don't update the FSM information for page on caller's behalf. Caller might
- * also need to account for a reduction in the length of the line pointer
- * array following array truncation by us.
- *
- * params contains the input parameters used to control freezing and pruning
- * behavior. See the definition of PruneFreezeParams for more on what each
- * parameter does.
- *
- * If the HEAP_PRUNE_FREEZE option is set in params, we will freeze tuples if
- * it's required in order to advance relfrozenxid / relminmxid, or if it's
- * considered advantageous for overall system performance to do so now. The
- * 'params.cutoffs', 'presult', 'new_relfrozen_xid' and 'new_relmin_mxid'
- * arguments are required when freezing.
- *
- * If HEAP_PAGE_PRUNE_UPDATE_VIS is set in params and the visibility status of
- * the page has changed, we will update the VM at the same time as pruning and
- * freezing the heap page. We will also update presult->old_vmbits and
- * presult->new_vmbits with the state of the VM before and after updating it
- * for the caller to use in bookkeeping.
- *
- * presult contains output parameters needed by callers, such as the number of
- * tuples removed and the offsets of dead items on the page after pruning.
- * heap_page_prune_and_freeze() is responsible for initializing it. Required
- * by all callers.
- *
- * off_loc is the offset location required by the caller to use in error
- * callback.
- *
- * new_relfrozen_xid and new_relmin_mxid must provided by the caller if the
- * HEAP_PRUNE_FREEZE option is set in params. On entry, they contain the
- * oldest XID and multi-XID seen on the relation so far. They will be updated
- * with oldest values present on the page after pruning. After processing the
- * whole relation, VACUUM can use these values as the new
- * relfrozenxid/relminmxid for the relation.
- */
-void
-heap_page_prune_and_freeze(PruneFreezeParams *params,
- PruneFreezeResult *presult,
- OffsetNumber *off_loc,
- TransactionId *new_relfrozen_xid,
- MultiXactId *new_relmin_mxid)
+static void
+prune_freeze_setup(PruneFreezeParams *params, PruneState *prstate,
+ TransactionId *new_relfrozen_xid,
+ MultiXactId *new_relmin_mxid,
+ PruneFreezeResult *presult)
{
- Buffer buffer = params->buffer;
- Buffer vmbuffer = params->vmbuffer;
- Page page = BufferGetPage(buffer);
- BlockNumber blockno = BufferGetBlockNumber(buffer);
- OffsetNumber offnum,
- maxoff;
- PruneState prstate;
- HeapTupleData tup;
- bool do_freeze;
- bool do_prune;
- bool do_hint_prune;
- bool do_set_vm;
- bool do_set_pd_vis;
- bool did_tuple_hint_fpi;
- int64 fpi_before = pgWalUsage.wal_fpi;
- TransactionId frz_conflict_horizon = InvalidTransactionId;
- TransactionId conflict_xid = InvalidTransactionId;
- uint8 new_vmbits = 0;
- uint8 old_vmbits = 0;
-
/* Copy parameters to prstate */
- prstate.vistest = params->vistest;
- prstate.mark_unused_now =
+ prstate->vistest = params->vistest;
+ prstate->mark_unused_now =
(params->options & HEAP_PAGE_PRUNE_MARK_UNUSED_NOW) != 0;
- prstate.attempt_freeze = (params->options & HEAP_PAGE_PRUNE_FREEZE) != 0;
- prstate.attempt_update_vm =
+ prstate->attempt_freeze = (params->options & HEAP_PAGE_PRUNE_FREEZE) != 0;
+ prstate->attempt_update_vm =
(params->options & HEAP_PAGE_PRUNE_UPDATE_VIS) != 0;
- prstate.cutoffs = params->cutoffs;
+ prstate->cutoffs = params->cutoffs;
/*
* Our strategy is to scan the page and make lists of items to change,
@@ -678,37 +616,37 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
* prunable, we will save the lowest relevant XID in new_prune_xid. Also
* initialize the rest of our working state.
*/
- prstate.new_prune_xid = InvalidTransactionId;
- prstate.latest_xid_removed = InvalidTransactionId;
- prstate.nredirected = prstate.ndead = prstate.nunused = prstate.nfrozen = 0;
- prstate.nroot_items = 0;
- prstate.nheaponly_items = 0;
+ prstate->new_prune_xid = InvalidTransactionId;
+ prstate->latest_xid_removed = InvalidTransactionId;
+ prstate->nredirected = prstate->ndead = prstate->nunused = prstate->nfrozen = 0;
+ prstate->nroot_items = 0;
+ prstate->nheaponly_items = 0;
/* initialize page freezing working state */
- prstate.pagefrz.freeze_required = false;
- if (prstate.attempt_freeze)
+ prstate->pagefrz.freeze_required = false;
+ if (prstate->attempt_freeze)
{
Assert(new_relfrozen_xid && new_relmin_mxid);
- prstate.pagefrz.FreezePageRelfrozenXid = *new_relfrozen_xid;
- prstate.pagefrz.NoFreezePageRelfrozenXid = *new_relfrozen_xid;
- prstate.pagefrz.FreezePageRelminMxid = *new_relmin_mxid;
- prstate.pagefrz.NoFreezePageRelminMxid = *new_relmin_mxid;
+ prstate->pagefrz.FreezePageRelfrozenXid = *new_relfrozen_xid;
+ prstate->pagefrz.NoFreezePageRelfrozenXid = *new_relfrozen_xid;
+ prstate->pagefrz.FreezePageRelminMxid = *new_relmin_mxid;
+ prstate->pagefrz.NoFreezePageRelminMxid = *new_relmin_mxid;
}
else
{
Assert(new_relfrozen_xid == NULL && new_relmin_mxid == NULL);
- prstate.pagefrz.FreezePageRelminMxid = InvalidMultiXactId;
- prstate.pagefrz.NoFreezePageRelminMxid = InvalidMultiXactId;
- prstate.pagefrz.FreezePageRelfrozenXid = InvalidTransactionId;
- prstate.pagefrz.NoFreezePageRelfrozenXid = InvalidTransactionId;
+ prstate->pagefrz.FreezePageRelminMxid = InvalidMultiXactId;
+ prstate->pagefrz.NoFreezePageRelminMxid = InvalidMultiXactId;
+ prstate->pagefrz.FreezePageRelfrozenXid = InvalidTransactionId;
+ prstate->pagefrz.NoFreezePageRelfrozenXid = InvalidTransactionId;
}
- prstate.ndeleted = 0;
- prstate.live_tuples = 0;
- prstate.recently_dead_tuples = 0;
- prstate.hastup = false;
- prstate.lpdead_items = 0;
- prstate.deadoffsets = presult->deadoffsets;
+ prstate->ndeleted = 0;
+ prstate->live_tuples = 0;
+ prstate->recently_dead_tuples = 0;
+ prstate->hastup = false;
+ prstate->lpdead_items = 0;
+ prstate->deadoffsets = presult->deadoffsets;
/*
* Track whether the page could be marked all-visible and/or all-frozen.
@@ -736,20 +674,20 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
* bookkeeping. In this case, initializing all_visible to false allows
* heap_prune_record_unchanged_lp_normal() to bypass unnecessary work.
*/
- if (prstate.attempt_freeze)
+ if (prstate->attempt_freeze)
{
- prstate.all_visible = true;
- prstate.all_frozen = true;
+ prstate->all_visible = true;
+ prstate->all_frozen = true;
}
- else if (prstate.attempt_update_vm)
+ else if (prstate->attempt_update_vm)
{
- prstate.all_visible = true;
- prstate.all_frozen = false;
+ prstate->all_visible = true;
+ prstate->all_frozen = false;
}
else
{
- prstate.all_visible = false;
- prstate.all_frozen = false;
+ prstate->all_visible = false;
+ prstate->all_frozen = false;
}
/*
@@ -761,10 +699,14 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
* used to calculate the snapshot conflict horizon when updating the VM
* and/or freezing all the tuples on the page.
*/
- prstate.visibility_cutoff_xid = InvalidTransactionId;
+ prstate->visibility_cutoff_xid = InvalidTransactionId;
+}
- maxoff = PageGetMaxOffsetNumber(page);
- tup.t_tableOid = RelationGetRelid(params->relation);
+static void
+prune_freeze_plan(PruneState *prstate, BlockNumber blockno, Buffer buffer, Page page,
+ OffsetNumber maxoff, OffsetNumber *off_loc, HeapTuple tup)
+{
+ OffsetNumber offnum;
/*
* Determine HTSV for all tuples, and queue them up for processing as HOT
@@ -799,13 +741,13 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
*/
*off_loc = offnum;
- prstate.processed[offnum] = false;
- prstate.htsv[offnum] = -1;
+ prstate->processed[offnum] = false;
+ prstate->htsv[offnum] = -1;
/* Nothing to do if slot doesn't contain a tuple */
if (!ItemIdIsUsed(itemid))
{
- heap_prune_record_unchanged_lp_unused(page, &prstate, offnum);
+ heap_prune_record_unchanged_lp_unused(page, prstate, offnum);
continue;
}
@@ -815,17 +757,17 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
* If the caller set mark_unused_now true, we can set dead line
* pointers LP_UNUSED now.
*/
- if (unlikely(prstate.mark_unused_now))
- heap_prune_record_unused(&prstate, offnum, false);
+ if (unlikely(prstate->mark_unused_now))
+ heap_prune_record_unused(prstate, offnum, false);
else
- heap_prune_record_unchanged_lp_dead(page, &prstate, offnum);
+ heap_prune_record_unchanged_lp_dead(page, prstate, offnum);
continue;
}
if (ItemIdIsRedirected(itemid))
{
/* This is the start of a HOT chain */
- prstate.root_items[prstate.nroot_items++] = offnum;
+ prstate->root_items[prstate->nroot_items++] = offnum;
continue;
}
@@ -835,25 +777,19 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
* Get the tuple's visibility status and queue it up for processing.
*/
htup = (HeapTupleHeader) PageGetItem(page, itemid);
- tup.t_data = htup;
- tup.t_len = ItemIdGetLength(itemid);
- ItemPointerSet(&tup.t_self, blockno, offnum);
+ tup->t_data = htup;
+ tup->t_len = ItemIdGetLength(itemid);
+ ItemPointerSet(&tup->t_self, blockno, offnum);
- prstate.htsv[offnum] = heap_prune_satisfies_vacuum(&prstate, &tup,
- buffer);
+ prstate->htsv[offnum] = heap_prune_satisfies_vacuum(prstate, tup,
+ buffer);
if (!HeapTupleHeaderIsHeapOnly(htup))
- prstate.root_items[prstate.nroot_items++] = offnum;
+ prstate->root_items[prstate->nroot_items++] = offnum;
else
- prstate.heaponly_items[prstate.nheaponly_items++] = offnum;
+ prstate->heaponly_items[prstate->nheaponly_items++] = offnum;
}
- /*
- * If checksums are enabled, heap_prune_satisfies_vacuum() may have caused
- * an FPI to be emitted.
- */
- did_tuple_hint_fpi = fpi_before != pgWalUsage.wal_fpi;
-
/*
* Process HOT chains.
*
@@ -865,30 +801,30 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
* the page instead of using the root_items array, also did it in
* ascending offset number order.)
*/
- for (int i = prstate.nroot_items - 1; i >= 0; i--)
+ for (int i = prstate->nroot_items - 1; i >= 0; i--)
{
- offnum = prstate.root_items[i];
+ offnum = prstate->root_items[i];
/* Ignore items already processed as part of an earlier chain */
- if (prstate.processed[offnum])
+ if (prstate->processed[offnum])
continue;
/* see preceding loop */
*off_loc = offnum;
/* Process this item or chain of items */
- heap_prune_chain(page, blockno, maxoff, offnum, &prstate);
+ heap_prune_chain(page, blockno, maxoff, offnum, prstate);
}
/*
* Process any heap-only tuples that were not already processed as part of
* a HOT chain.
*/
- for (int i = prstate.nheaponly_items - 1; i >= 0; i--)
+ for (int i = prstate->nheaponly_items - 1; i >= 0; i--)
{
- offnum = prstate.heaponly_items[i];
+ offnum = prstate->heaponly_items[i];
- if (prstate.processed[offnum])
+ if (prstate->processed[offnum])
continue;
/* see preceding loop */
@@ -907,7 +843,7 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
* return true for an XMIN_INVALID tuple, so this code will work even
* when there were sequential updates within the aborted transaction.)
*/
- if (prstate.htsv[offnum] == HEAPTUPLE_DEAD)
+ if (prstate->htsv[offnum] == HEAPTUPLE_DEAD)
{
ItemId itemid = PageGetItemId(page, offnum);
HeapTupleHeader htup = (HeapTupleHeader) PageGetItem(page, itemid);
@@ -915,8 +851,8 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
if (likely(!HeapTupleHeaderIsHotUpdated(htup)))
{
HeapTupleHeaderAdvanceConflictHorizon(htup,
- &prstate.latest_xid_removed);
- heap_prune_record_unused(&prstate, offnum, true);
+ &prstate->latest_xid_removed);
+ heap_prune_record_unused(prstate, offnum, true);
}
else
{
@@ -933,7 +869,7 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
}
}
else
- heap_prune_record_unchanged_lp_normal(page, &prstate, offnum);
+ heap_prune_record_unchanged_lp_normal(page, prstate, offnum);
}
/* We should now have processed every tuple exactly once */
@@ -944,12 +880,110 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
{
*off_loc = offnum;
- Assert(prstate.processed[offnum]);
+ Assert(prstate->processed[offnum]);
}
#endif
+ /*
+ * After processing all the live tuples on the page, if the newest xmin
+ * amongst them is not visible to everyone, the page cannot be
+ * all-visible.
+ */
+ if (prstate->all_visible &&
+ TransactionIdIsNormal(prstate->visibility_cutoff_xid) &&
+ !GlobalVisXidVisibleToAll(prstate->vistest, prstate->visibility_cutoff_xid))
+ prstate->all_visible = prstate->all_frozen = false;
+
/* Clear the offset information once we have processed the given page. */
*off_loc = InvalidOffsetNumber;
+}
+
+/*
+ * Prune and repair fragmentation and potentially freeze tuples on the
+ * specified page. If the page's visibility status has changed, update it in
+ * the VM.
+ *
+ * Caller must have pin and buffer cleanup lock on the page. Note that we
+ * don't update the FSM information for page on caller's behalf. Caller might
+ * also need to account for a reduction in the length of the line pointer
+ * array following array truncation by us.
+ *
+ * params contains the input parameters used to control freezing and pruning
+ * behavior. See the definition of PruneFreezeParams for more on what each
+ * parameter does.
+ *
+ * If the HEAP_PRUNE_FREEZE option is set in params, we will freeze tuples if
+ * it's required in order to advance relfrozenxid / relminmxid, or if it's
+ * considered advantageous for overall system performance to do so now. The
+ * 'params.cutoffs', 'presult', 'new_relfrozen_xid' and 'new_relmin_mxid'
+ * arguments are required when freezing.
+ *
+ * If HEAP_PAGE_PRUNE_UPDATE_VIS is set in params and the visibility status of
+ * the page has changed, we will update the VM at the same time as pruning and
+ * freezing the heap page. We will also update presult->old_vmbits and
+ * presult->new_vmbits with the state of the VM before and after updating it
+ * for the caller to use in bookkeeping.
+ *
+ * presult contains output parameters needed by callers, such as the number of
+ * tuples removed and the offsets of dead items on the page after pruning.
+ * heap_page_prune_and_freeze() is responsible for initializing it. Required
+ * by all callers.
+ *
+ * off_loc is the offset location required by the caller to use in error
+ * callback.
+ *
+ * new_relfrozen_xid and new_relmin_mxid must provided by the caller if the
+ * HEAP_PRUNE_FREEZE option is set in params. On entry, they contain the
+ * oldest XID and multi-XID seen on the relation so far. They will be updated
+ * with oldest values present on the page after pruning. After processing the
+ * whole relation, VACUUM can use these values as the new
+ * relfrozenxid/relminmxid for the relation.
+ */
+void
+heap_page_prune_and_freeze(PruneFreezeParams *params,
+ PruneFreezeResult *presult,
+ OffsetNumber *off_loc,
+ TransactionId *new_relfrozen_xid,
+ MultiXactId *new_relmin_mxid)
+{
+ Buffer buffer = params->buffer;
+ Buffer vmbuffer = params->vmbuffer;
+ Page page = BufferGetPage(buffer);
+ BlockNumber blockno = BufferGetBlockNumber(buffer);
+ OffsetNumber maxoff;
+ PruneState prstate;
+ HeapTupleData tup;
+ bool do_freeze;
+ bool do_prune;
+ bool do_hint_prune;
+ bool do_set_vm;
+ bool do_set_pd_vis;
+ bool did_tuple_hint_fpi;
+ int64 fpi_before = pgWalUsage.wal_fpi;
+ TransactionId frz_conflict_horizon = InvalidTransactionId;
+ TransactionId conflict_xid = InvalidTransactionId;
+ uint8 new_vmbits = 0;
+ uint8 old_vmbits = 0;
+
+ maxoff = PageGetMaxOffsetNumber(page);
+ tup.t_tableOid = RelationGetRelid(params->relation);
+
+ /* Initialize needed state in prstate */
+ prune_freeze_setup(params, &prstate, new_relfrozen_xid, new_relmin_mxid, presult);
+
+ /*
+ * Examine all line pointers and tuple visibility information to determine
+ * which line pointers should change state and which tuples may be frozen.
+ * Prepare queue of state changes to later be executed in a critical
+ * section.
+ */
+ prune_freeze_plan(&prstate, blockno, buffer, page, maxoff, off_loc, &tup);
+
+ /*
+ * If checksums are enabled, heap_prune_satisfies_vacuum() may have caused
+ * an FPI to be emitted.
+ */
+ did_tuple_hint_fpi = fpi_before != pgWalUsage.wal_fpi;
do_prune = prstate.nredirected > 0 ||
prstate.ndead > 0 ||
@@ -963,16 +997,6 @@ heap_page_prune_and_freeze(PruneFreezeParams *params,
do_hint_prune = ((PageHeader) page)->pd_prune_xid != prstate.new_prune_xid ||
PageIsFull(page);
- /*
- * After processing all the live tuples on the page, if the newest xmin
- * amongst them is not visible to everyone, the page cannot be
- * all-visible.
- */
- if (prstate.all_visible &&
- TransactionIdIsNormal(prstate.visibility_cutoff_xid) &&
- !GlobalVisXidVisibleToAll(prstate.vistest, prstate.visibility_cutoff_xid))
- prstate.all_visible = prstate.all_frozen = false;
-
/*
* Decide if we want to go ahead with freezing according to the freeze
* plans we prepared, or not.
--
2.43.0
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To: [email protected]
Cc: [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]
Subject: Re: eliminate xl_heap_visible to reduce WAL (and eventually set VM on-access)
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