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* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v4 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index f8c4dada7c9..72c8aa7650b 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -257,6 +258,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 47ce61e5093..5e509153656 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -285,9 +285,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0fdbaf79780..d78633cae44 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -510,6 +511,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v5 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
---
src/backend/access/transam/varsup.c | 4 ++++
src/backend/utils/activity/pgstat_backend.c | 2 ++
src/include/pgstat.h | 2 ++
3 files changed, 8 insertions(+)
43.8% src/backend/access/transam/
36.6% src/backend/utils/activity/
19.4% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index 1441a051773..fe625d00f7d 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -24,6 +24,7 @@
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "utils/lsyscache.h"
+#include "utils/pgstat_internal.h"
#include "utils/syscache.h"
@@ -261,6 +262,9 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ PendingBackendStats.pending_xid_count++;
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 42bfb9cd38f..32ee48eab51 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -287,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += PendingBackendStats.pending_xid_count;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ PendingBackendStats.pending_xid_count = 0;
backend_has_xactstats = false;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5d73c4dfbcf..780ca4b3ac0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -525,6 +525,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -543,6 +544,7 @@ typedef struct PgStat_BackendPending
*/
PgStat_Counter pending_xact_commit;
PgStat_Counter pending_xact_rollback;
+ PgStat_Counter pending_xid_count;
} PgStat_BackendPending;
/*
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v3 2/3] Adding XID generation count per backend
@ 2025-08-08 15:58 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Bertrand Drouvot @ 2025-08-08 15:58 UTC (permalink / raw)
This commit adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
---
src/backend/access/transam/varsup.c | 2 ++
src/backend/utils/activity/pgstat_backend.c | 6 +++++-
src/include/pgstat.h | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)
10.1% src/backend/access/transam/
69.3% src/backend/utils/activity/
20.5% src/include/
diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c
index fe895787cb7..26c72cbe091 100644
--- a/src/backend/access/transam/varsup.c
+++ b/src/backend/access/transam/varsup.c
@@ -21,6 +21,7 @@
#include "access/xlogutils.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
+#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
@@ -257,6 +258,7 @@ GetNewTransactionId(bool isSubXact)
/* LWLockRelease acts as barrier */
MyProc->xid = xid;
ProcGlobal->xids[MyProc->pgxactoff] = xid;
+ XidGenCount++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index bf164854c4b..8b530c510b9 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -52,6 +52,8 @@ static WalUsage prevBackendWalUsage;
*/
static bool backend_has_xactstats = false;
+PgStat_Counter XidGenCount = 0;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -285,9 +287,11 @@ pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+ shbackendent->stats.xid_count += XidGenCount;
PendingBackendStats.pending_xact_commit = 0;
PendingBackendStats.pending_xact_rollback = 0;
+ XidGenCount = 0;
backend_has_xactstats = false;
}
@@ -317,7 +321,7 @@ pgstat_flush_backend(bool nowait, bits32 flags)
has_pending_data = true;
/* Some transaction data pending? */
- if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && (backend_has_xactstats || XidGenCount > 0))
has_pending_data = true;
if (!has_pending_data)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 9efc0e10ebf..94dd24b3eac 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -492,6 +492,7 @@ typedef struct PgStat_Backend
PgStat_WalCounters wal_counters;
PgStat_Counter xact_commit;
PgStat_Counter xact_rollback;
+ PgStat_Counter xid_count;
} PgStat_Backend;
/* ---------
@@ -571,6 +572,8 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid,
extern bool pgstat_tracks_backend_bktype(BackendType bktype);
extern void pgstat_create_backend(ProcNumber procnum);
+extern PGDLLIMPORT PgStat_Counter XidGenCount;
+
/*
* Functions in pgstat_bgwriter.c
*/
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0003-Adding-the-pg_stat_backend-view.patch"
^ permalink raw reply [nested|flat] 196+ messages in thread
* [PATCH v48 3/7] Rename cluster.c/h -> repack.c/h
@ 2026-03-31 16:55 Álvaro Herrera <[email protected]>
0 siblings, 0 replies; 196+ messages in thread
From: Álvaro Herrera @ 2026-03-31 16:55 UTC (permalink / raw)
---
src/backend/commands/Makefile | 2 +-
src/backend/commands/matview.c | 2 +-
src/backend/commands/meson.build | 2 +-
src/backend/commands/{cluster.c => repack.c} | 6 +++---
src/backend/commands/tablecmds.c | 2 +-
src/backend/commands/vacuum.c | 6 +++---
src/backend/storage/ipc/procsignal.c | 1 +
src/backend/tcop/postgres.c | 1 +
src/backend/tcop/utility.c | 2 +-
src/include/commands/{cluster.h => repack.h} | 12 ++++++------
10 files changed, 19 insertions(+), 17 deletions(-)
rename src/backend/commands/{cluster.c => repack.c} (99%)
rename src/include/commands/{cluster.h => repack.h} (90%)
diff --git a/src/backend/commands/Makefile b/src/backend/commands/Makefile
index c10fdba2bbb..fe1bba3a9b9 100644
--- a/src/backend/commands/Makefile
+++ b/src/backend/commands/Makefile
@@ -18,7 +18,6 @@ OBJS = \
amcmds.o \
analyze.o \
async.o \
- cluster.o \
collationcmds.o \
comment.o \
constraint.o \
@@ -51,6 +50,7 @@ OBJS = \
proclang.o \
propgraphcmds.o \
publicationcmds.o \
+ repack.o \
schemacmds.o \
seclabel.o \
sequence.o \
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 81a55a33ef2..d492bddcd73 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -24,8 +24,8 @@
#include "catalog/namespace.h"
#include "catalog/pg_am.h"
#include "catalog/pg_opclass.h"
-#include "commands/cluster.h"
#include "commands/matview.h"
+#include "commands/repack.h"
#include "commands/tablecmds.h"
#include "commands/tablespace.h"
#include "executor/executor.h"
diff --git a/src/backend/commands/meson.build b/src/backend/commands/meson.build
index 90c7e37a429..f624aae74af 100644
--- a/src/backend/commands/meson.build
+++ b/src/backend/commands/meson.build
@@ -6,7 +6,6 @@ backend_sources += files(
'amcmds.c',
'analyze.c',
'async.c',
- 'cluster.c',
'collationcmds.c',
'comment.c',
'constraint.c',
@@ -39,6 +38,7 @@ backend_sources += files(
'proclang.c',
'propgraphcmds.c',
'publicationcmds.c',
+ 'repack.c',
'schemacmds.c',
'seclabel.c',
'sequence.c',
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/repack.c
similarity index 99%
rename from src/backend/commands/cluster.c
rename to src/backend/commands/repack.c
index f241e18b153..20f0a572236 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/repack.c
@@ -1,6 +1,6 @@
/*-------------------------------------------------------------------------
*
- * cluster.c
+ * repack.c
* REPACK a table; formerly known as CLUSTER. VACUUM FULL also uses
* parts of this code.
*
@@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
- * src/backend/commands/cluster.c
+ * src/backend/commands/repack.c
*
*-------------------------------------------------------------------------
*/
@@ -33,9 +33,9 @@
#include "catalog/pg_am.h"
#include "catalog/pg_inherits.h"
#include "catalog/toasting.h"
-#include "commands/cluster.h"
#include "commands/defrem.h"
#include "commands/progress.h"
+#include "commands/repack.h"
#include "commands/tablecmds.h"
#include "commands/vacuum.h"
#include "miscadmin.h"
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 8b4ebc6f226..505473ed852 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -57,10 +57,10 @@
#include "catalog/storage.h"
#include "catalog/storage_xlog.h"
#include "catalog/toasting.h"
-#include "commands/cluster.h"
#include "commands/comment.h"
#include "commands/defrem.h"
#include "commands/event_trigger.h"
+#include "commands/repack.h"
#include "commands/sequence.h"
#include "commands/tablecmds.h"
#include "commands/tablespace.h"
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 0ed363d1c85..b179b62b5c8 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -9,7 +9,7 @@
*
* VACUUM for heap AM is implemented in vacuumlazy.c, parallel vacuum in
* vacuumparallel.c, ANALYZE in analyze.c, and VACUUM FULL is a variant of
- * CLUSTER, handled in cluster.c.
+ * REPACK, handled in repack.c.
*
*
* Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
@@ -38,9 +38,9 @@
#include "catalog/pg_database.h"
#include "catalog/pg_inherits.h"
#include "commands/async.h"
-#include "commands/cluster.h"
#include "commands/defrem.h"
#include "commands/progress.h"
+#include "commands/repack.h"
#include "commands/vacuum.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
@@ -2293,7 +2293,7 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
if ((params.options & VACOPT_VERBOSE) != 0)
cluster_params.options |= CLUOPT_VERBOSE;
- /* VACUUM FULL is a variant of REPACK; see cluster.c */
+ /* VACUUM FULL is a variant of REPACK; see repack.c */
cluster_rel(REPACK_COMMAND_VACUUMFULL, rel, InvalidOid,
&cluster_params);
/* cluster_rel closes the relation, but keeps lock */
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 7e017c8d53b..7cef6e43661 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -19,6 +19,7 @@
#include "access/parallel.h"
#include "commands/async.h"
+#include "commands/repack.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "port/pg_bitutils.h"
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 10be60011ad..9fbaa5c00f0 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -39,6 +39,7 @@
#include "commands/event_trigger.h"
#include "commands/explain_state.h"
#include "commands/prepare.h"
+#include "commands/repack.h"
#include "common/pg_prng.h"
#include "jit/jit.h"
#include "libpq/libpq.h"
diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
index 2b609bfc824..5f8c766c4be 100644
--- a/src/backend/tcop/utility.c
+++ b/src/backend/tcop/utility.c
@@ -26,7 +26,6 @@
#include "catalog/toasting.h"
#include "commands/alter.h"
#include "commands/async.h"
-#include "commands/cluster.h"
#include "commands/collationcmds.h"
#include "commands/comment.h"
#include "commands/conversioncmds.h"
@@ -46,6 +45,7 @@
#include "commands/proclang.h"
#include "commands/propgraphcmds.h"
#include "commands/publicationcmds.h"
+#include "commands/repack.h"
#include "commands/schemacmds.h"
#include "commands/seclabel.h"
#include "commands/sequence.h"
diff --git a/src/include/commands/cluster.h b/src/include/commands/repack.h
similarity index 90%
rename from src/include/commands/cluster.h
rename to src/include/commands/repack.h
index d6b62c747e8..85061158b0c 100644
--- a/src/include/commands/cluster.h
+++ b/src/include/commands/repack.h
@@ -1,17 +1,17 @@
/*-------------------------------------------------------------------------
*
- * cluster.h
- * header file for postgres cluster command stuff
+ * repack.h
+ * header file for the REPACK command
*
* Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
* Portions Copyright (c) 1994-5, Regents of the University of California
*
- * src/include/commands/cluster.h
+ * src/include/commands/repack.h
*
*-------------------------------------------------------------------------
*/
-#ifndef CLUSTER_H
-#define CLUSTER_H
+#ifndef REPACK_H
+#define REPACK_H
#include "nodes/parsenodes.h"
#include "parser/parse_node.h"
@@ -52,4 +52,4 @@ extern void finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
MultiXactId cutoffMulti,
char newrelpersistence);
-#endif /* CLUSTER_H */
+#endif /* REPACK_H */
--
2.47.3
--qfkt2ktdpcfeypib
Content-Type: text/x-diff; charset=utf-8
Content-Disposition: attachment;
filename="v48-0004-Add-CONCURRENTLY-option-to-REPACK-command.patch"
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2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
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2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
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2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v5 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v4 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2025-08-08 15:58 [PATCH v3 2/3] Adding XID generation count per backend Bertrand Drouvot <[email protected]>
2026-03-31 16:55 [PATCH v48 3/7] Rename cluster.c/h -> repack.c/h Álvaro Herrera <[email protected]>
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