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[PATCH v21 6/8] Row pattern recognition patch (docs).
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* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
  0 siblings, 0 replies; 166+ messages in thread

From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)

---
 doc/src/sgml/advanced.sgml   | 82 ++++++++++++++++++++++++++++++++++++
 doc/src/sgml/func.sgml       | 54 ++++++++++++++++++++++++
 doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
 3 files changed, 172 insertions(+), 2 deletions(-)

diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos &lt; 3;
     <literal>rank</literal> less than 3.
    </para>
 
+   <para>
+    Row pattern common syntax can be used to perform row pattern recognition
+    in a query. The row pattern common syntax includes two sub
+    clauses: <literal>DEFINE</literal>
+    and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+    definition variables along with an expression. The expression must be a
+    logical expression, which means it must
+    return <literal>TRUE</literal>, <literal>FALSE</literal>
+    or <literal>NULL</literal>. The expression may comprise column references
+    and functions. Window functions, aggregate functions and subqueries are
+    not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price &lt;= 100,
+ UP AS price &gt; PREV(price),
+ DOWN AS price &lt; PREV(price)
+</programlisting>
+
+    Note that <function>PREV</function> returns the price column in the
+    previous row if it's called in a context of row pattern recognition. Thus in
+    the second line the definition variable "UP" is <literal>TRUE</literal>
+    when the price column in the current row is greater than the price column
+    in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+    the price column in the current row is lower than the price column in the
+    previous row.
+   </para>
+   <para>
+    Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+    used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+    certain conditions.  For example following <literal>PATTERN</literal>
+    defines that a row starts with the condition "LOWPRICE", then one or more
+    rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+    "+" means one or more matches. Also you can use "*", which means zero or
+    more matches. If a sequence of rows which satisfies the PATTERN is found,
+    in the starting row of the sequence of rows all window functions and
+    aggregates are shown in the target list. Note that aggregations only look
+    into the matched rows, rather than whole frame. On the second or
+    subsequent rows all window functions are NULL. Aggregates are NULL or 0
+    (count case) depending on its aggregation definition. For rows that do not
+    match on the PATTERN, all window functions and aggregates are shown AS
+    NULL too, except count showing 0. This is because the rows do not match,
+    thus they are in an empty frame. Example of a <literal>SELECT</literal>
+    using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+    is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+  LOWPRICE AS price &lt;= 100,
+  UP AS price &gt; PREV(price),
+  DOWN AS price &lt; PREV(price)
+);
+</programlisting>
+<screen>
+ company  |   tdate    | price | first_value | max | count 
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 |   100 |         100 | 200 |     4
+ company1 | 2023-07-02 |   200 |             |     |     0
+ company1 | 2023-07-03 |   150 |             |     |     0
+ company1 | 2023-07-04 |   140 |             |     |     0
+ company1 | 2023-07-05 |   150 |             |     |     0
+ company1 | 2023-07-06 |    90 |          90 | 130 |     4
+ company1 | 2023-07-07 |   110 |             |     |     0
+ company1 | 2023-07-08 |   130 |             |     |     0
+ company1 | 2023-07-09 |   120 |             |     |     0
+ company1 | 2023-07-10 |   130 |             |     |     0
+(10 rows)
+</screen>
+   </para>
+
    <para>
     When a query involves multiple window functions, it is possible to write
     out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
         returns <literal>NULL</literal> if there is no such row.
        </para></entry>
       </row>
+
      </tbody>
     </tgroup>
    </table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
    Other frame specifications can be used to obtain other effects.
   </para>
 
+  <para>
+   Row pattern recognition navigation functions are listed in
+   <xref linkend="functions-rpr-navigation-table"/>.  These functions
+   can be used to describe DEFINE clause of Row pattern recognition.
+  </para>
+
+   <table id="functions-rpr-navigation-table">
+    <title>Row Pattern Navigation Functions</title>
+    <tgroup cols="1">
+     <thead>
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        Function
+       </para>
+       <para>
+        Description
+       </para></entry>
+      </row>
+     </thead>
+
+     <tbody>
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <indexterm>
+         <primary>prev</primary>
+        </indexterm>
+        <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+        <returnvalue>anyelement</returnvalue>
+       </para>
+       <para>
+        Returns the column value at the previous row;
+        returns NULL if there is no previous row in the window frame.
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <indexterm>
+         <primary>next</primary>
+        </indexterm>
+        <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+        <returnvalue>anyelement</returnvalue>
+       </para>
+       <para>
+        Returns the column value at the next row;
+        returns NULL if there is no next row in the window frame.
+       </para></entry>
+      </row>
+
+     </tbody>
+    </tgroup>
+   </table>
+
   <note>
    <para>
     The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
     The <replaceable class="parameter">frame_clause</replaceable> can be one of
 
 <synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
 </synopsis>
 
     where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
     a given peer group will be in the frame or excluded from it.
    </para>
 
+   <para>
+    The
+    optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+    defines the <firstterm>row pattern recognition condition</firstterm> for
+    this
+    window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+    includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+    ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+    how to proceed to next row position after a match
+    found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+    default) next row position is next to the last row of previous match. On
+    the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+    row position is always next to the last row of previous
+    match. <literal>DEFINE</literal> defines definition variables along with a
+    boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+    that satisfies certain conditions using variables defined
+    in <literal>DEFINE</literal> clause. If the variable is not defined in
+    the <literal>DEFINE</literal> clause, it is implicitly assumed
+    following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+    Note that the maximu number of variables defined
+    in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+   </para>
+
    <para>
     The purpose of a <literal>WINDOW</literal> clause is to specify the
     behavior of <firstterm>window functions</firstterm> appearing in the query's
-- 
2.25.1


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 filename="v21-0007-Row-pattern-recognition-patch-tests.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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Content-Disposition: attachment;
	filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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
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Content-Disposition: attachment;
	filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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
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Content-Disposition: attachment;
	filename="v3-0003-Adding-the-pg_stat_backend-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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
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	filename="v3-0003-Adding-the-pg_stat_backend-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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Content-Disposition: attachment;
	filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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	filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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	filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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	filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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	filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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] 166+ 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; 166+ 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
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Content-Disposition: attachment;
	filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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	filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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	filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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
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	filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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
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Content-Disposition: attachment;
	filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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Content-Disposition: attachment;
	filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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	filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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Content-Disposition: attachment;
	filename="v3-0003-Adding-the-pg_stat_backend-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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	filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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	filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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
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Content-Disposition: attachment;
	filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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Content-Disposition: attachment;
	filename="v3-0003-Adding-the-pg_stat_backend-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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] 166+ 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; 166+ 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
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Content-Disposition: attachment;
	filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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
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Content-Disposition: attachment;
	filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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	filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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] 166+ 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; 166+ 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
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	filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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	filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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	filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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	filename="v4-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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	filename="v3-0003-Adding-the-pg_stat_backend-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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	filename="v5-0003-Adding-the-pg_stat_backend_transaction-view.patch"



^ permalink  raw  reply  [nested|flat] 166+ 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; 166+ 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
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^ permalink  raw  reply  [nested|flat] 166+ messages in thread

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Thread overview: 166+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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]>
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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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]>

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