database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2026-10-23 13:29:09 +03:00
Code Activity

Add new pgstats routine to split pending data setup

Browse Source 
This commit adds pgstat_prep_pending_from_entry_ref(), a new pgstats
routine that is able to prepare an existing PgStat_EntryRef to receive
pending stats.  This split gives a way for callers to obtain first a
reference via pgstat_get_entry_ref(), then set up pending data as two
separate, distinctive, steps.

Previously, the only way to get an entry reference with pending data
ready was pgstat_prep_pending_entry(), which bundles lookup, creation,
and pending setup in a single call.  Callers that need finer control
over the entry creation had no way to attach pending data to an
already-obtained entry reference.  One case where this has shown to
matter for a stats kind is where one wants to check some capacity (for
example where a GUC bounds the maximum numer of entries allowed) before
deciding if a new entry should be created.  So this split can help in
reducing calls to pgstat_get_entry_ref(), meaning less shmem hash table
lookups.

The only logical ordering change is that pgStatPendingContext is
initialized after calling pgstat_get_entry_ref() in
pgstat_prep_pending_entry().  This does not matter in practice.

pgstat_prep_pending_entry() is refactored to use the new function
internally.  All the existing callers are unchanged.  Existing
out-of-core custom stats kinds should see no impact.

Author: Sami Imseih <samimseih@gmail.com>
Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/CAA5RZ0sV+TsLejUMhAM=PJoOm8u-t8ru7B67KvyLCy=19sM87g@mail.gmail.com
This commit is contained in:
Michael Paquier
2026-07-22 08:15:00 +09:00
parent 78758d3730
commit e65c331b8f
2 changed files with 36 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

55
src/backend/utils/activity/pgstat.c
View File

@@ -1311,29 +1311,10 @@ pgstat_prep_pending_entry(PgStat_Kind kind, Oid dboid, uint64 objid, bool *creat
{
PgStat_EntryRef *entry_ref;
/* need to be able to flush out */
Assert(pgstat_get_kind_info(kind)->flush_pending_cb != NULL);
if (unlikely(!pgStatPendingContext))
{
pgStatPendingContext =
AllocSetContextCreate(TopMemoryContext,
"PgStat Pending",
ALLOCSET_SMALL_SIZES);
}
entry_ref = pgstat_get_entry_ref(kind, dboid, objid,
true, created_entry);
if (entry_ref->pending == NULL)
{
size_t entrysize = pgstat_get_kind_info(kind)->pending_size;
Assert(entrysize != (size_t) -1);
entry_ref->pending = MemoryContextAllocZero(pgStatPendingContext, entrysize);
dlist_push_tail(&pgStatPending, &entry_ref->pending_node);
}
pgstat_prep_pending_from_entry_ref(entry_ref);
return entry_ref;
}
@@ -1377,6 +1358,40 @@ pgstat_delete_pending_entry(PgStat_EntryRef *entry_ref)
dlist_delete(&entry_ref->pending_node);
}
/*
* Prepare the given entry to receive pending stats, if not already done.
*/
void
pgstat_prep_pending_from_entry_ref(PgStat_EntryRef *entry_ref)
{
PgStat_Kind kind;
Assert(entry_ref != NULL);
kind = entry_ref->shared_entry->key.kind;
/* need to be able to flush out */
Assert(pgstat_get_kind_info(kind)->flush_pending_cb != NULL);
if (entry_ref->pending == NULL)
{
size_t entrysize = pgstat_get_kind_info(kind)->pending_size;
Assert(entrysize != (size_t) -1);
if (unlikely(!pgStatPendingContext))
{
pgStatPendingContext =
AllocSetContextCreate(TopMemoryContext,
"PgStat Pending",
ALLOCSET_SMALL_SIZES);
}
entry_ref->pending = MemoryContextAllocZero(pgStatPendingContext, entrysize);
dlist_push_tail(&pgStatPending, &entry_ref->pending_node);
}
}
/*
* Flush out pending variable-numbered stats.
*/

1
src/include/utils/pgstat_internal.h
View File

@@ -680,6 +680,7 @@ extern void pgstat_assert_is_up(void);
#endif
extern void pgstat_delete_pending_entry(PgStat_EntryRef *entry_ref);
extern void pgstat_prep_pending_from_entry_ref(PgStat_EntryRef *entry_ref);
extern PgStat_EntryRef *pgstat_prep_pending_entry(PgStat_Kind kind, Oid dboid,
uint64 objid,
bool *created_entry);