pgstat: move transactional code into pgstat_xact.c.

The transactional integration code is largely independent from the rest of
pgstat.c. Subsequent commits will add more related code.

Author: Andres Freund <[email protected]>
Reviewed-By: Thomas Munro <[email protected]>
Discussion: https://postgr.es/m/20220404041516[email protected]

diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index ef1cba61a6f5510d0ae0b1a73f6685859ea99db4..6757df397cf290c8a0051d48b81bd7308cf75392 100644 (file)
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -198,8 +198,6 @@ static time_t last_pgstat_start_time;
 
 static bool pgStatRunningInCollector = false;
 
-static PgStat_SubXactStatus *pgStatXactStack = NULL;
-
 /*
  * Info about current "snapshot" of stats file
  */
@@ -740,158 +738,6 @@ pgstat_initialize(void)
 }
 
 
-/* ------------------------------------------------------------
- * Transaction integration
- * ------------------------------------------------------------
- */
-
-/*
- * Called from access/transam/xact.c at top-level transaction commit/abort.
- */
-void
-AtEOXact_PgStat(bool isCommit, bool parallel)
-{
-       PgStat_SubXactStatus *xact_state;
-
-       AtEOXact_PgStat_Database(isCommit, parallel);
-
-       /* handle transactional stats information */
-       xact_state = pgStatXactStack;
-       if (xact_state != NULL)
-       {
-               Assert(xact_state->nest_level == 1);
-               Assert(xact_state->prev == NULL);
-
-               AtEOXact_PgStat_Relations(xact_state, isCommit);
-       }
-       pgStatXactStack = NULL;
-
-       /* Make sure any stats snapshot is thrown away */
-       pgstat_clear_snapshot();
-}
-
-/*
- * Called from access/transam/xact.c at subtransaction commit/abort.
- */
-void
-AtEOSubXact_PgStat(bool isCommit, int nestDepth)
-{
-       PgStat_SubXactStatus *xact_state;
-
-       /* merge the sub-transaction's transactional stats into the parent */
-       xact_state = pgStatXactStack;
-       if (xact_state != NULL &&
-               xact_state->nest_level >= nestDepth)
-       {
-               /* delink xact_state from stack immediately to simplify reuse case */
-               pgStatXactStack = xact_state->prev;
-
-               AtEOSubXact_PgStat_Relations(xact_state, isCommit, nestDepth);
-
-               pfree(xact_state);
-       }
-}
-
-/*
- * Save the transactional stats state at 2PC transaction prepare.
- */
-void
-AtPrepare_PgStat(void)
-{
-       PgStat_SubXactStatus *xact_state;
-
-       xact_state = pgStatXactStack;
-       if (xact_state != NULL)
-       {
-               Assert(xact_state->nest_level == 1);
-               Assert(xact_state->prev == NULL);
-
-               AtPrepare_PgStat_Relations(xact_state);
-       }
-}
-
-/*
- * Clean up after successful PREPARE.
- *
- * Note: AtEOXact_PgStat is not called during PREPARE.
- */
-void
-PostPrepare_PgStat(void)
-{
-       PgStat_SubXactStatus *xact_state;
-
-       /*
-        * We don't bother to free any of the transactional state, since it's all
-        * in TopTransactionContext and will go away anyway.
-        */
-       xact_state = pgStatXactStack;
-       if (xact_state != NULL)
-       {
-               Assert(xact_state->nest_level == 1);
-               Assert(xact_state->prev == NULL);
-
-               PostPrepare_PgStat_Relations(xact_state);
-       }
-       pgStatXactStack = NULL;
-
-       /* Make sure any stats snapshot is thrown away */
-       pgstat_clear_snapshot();
-}
-
-/*
- * Discard any data collected in the current transaction.  Any subsequent
- * request will cause new snapshots to be read.
- *
- * This is also invoked during transaction commit or abort to discard
- * the no-longer-wanted snapshot.
- */
-void
-pgstat_clear_snapshot(void)
-{
-       pgstat_assert_is_up();
-
-       /* Release memory, if any was allocated */
-       if (pgStatLocalContext)
-               MemoryContextDelete(pgStatLocalContext);
-
-       /* Reset variables */
-       pgStatLocalContext = NULL;
-       pgStatDBHash = NULL;
-       replSlotStatHash = NULL;
-       subscriptionStatHash = NULL;
-
-       /*
-        * Historically the backend_status.c facilities lived in this file, and
-        * were reset with the same function. For now keep it that way, and
-        * forward the reset request.
-        */
-       pgstat_clear_backend_activity_snapshot();
-}
-
-/*
- * Ensure (sub)transaction stack entry for the given nest_level exists, adding
- * it if needed.
- */
-PgStat_SubXactStatus *
-pgstat_xact_stack_level_get(int nest_level)
-{
-       PgStat_SubXactStatus *xact_state;
-
-       xact_state = pgStatXactStack;
-       if (xact_state == NULL || xact_state->nest_level != nest_level)
-       {
-               xact_state = (PgStat_SubXactStatus *)
-                       MemoryContextAlloc(TopTransactionContext,
-                                                          sizeof(PgStat_SubXactStatus));
-               xact_state->nest_level = nest_level;
-               xact_state->prev = pgStatXactStack;
-               xact_state->first = NULL;
-               pgStatXactStack = xact_state;
-       }
-       return xact_state;
-}
-
-
 /* ------------------------------------------------------------
  * Public functions used by backends follow
  * ------------------------------------------------------------
@@ -1319,6 +1165,36 @@ pgstat_send_inquiry(TimestampTz clock_time, TimestampTz cutoff_time, Oid databas
        pgstat_send(&msg, sizeof(msg));
 }
 
+/*
+ * Discard any data collected in the current transaction.  Any subsequent
+ * request will cause new snapshots to be read.
+ *
+ * This is also invoked during transaction commit or abort to discard
+ * the no-longer-wanted snapshot.
+ */
+void
+pgstat_clear_snapshot(void)
+{
+       pgstat_assert_is_up();
+
+       /* Release memory, if any was allocated */
+       if (pgStatLocalContext)
+               MemoryContextDelete(pgStatLocalContext);
+
+       /* Reset variables */
+       pgStatLocalContext = NULL;
+       pgStatDBHash = NULL;
+       replSlotStatHash = NULL;
+       subscriptionStatHash = NULL;
+
+       /*
+        * Historically the backend_status.c facilities lived in this file, and
+        * were reset with the same function. For now keep it that way, and
+        * forward the reset request.
+        */
+       pgstat_clear_backend_activity_snapshot();
+}
+
 /*
  * Support function for the SQL-callable pgstat* functions. Returns
  * the collected statistics for one database or NULL. NULL doesn't mean

diff --git a/src/backend/utils/activity/Makefile b/src/backend/utils/activity/Makefile
index 25a967ab7d70b4e795a990a8b31eea9dba656deb..791ba68e7e34df127ca1883e0e3ad474306cae9c 100644 (file)
--- a/src/backend/utils/activity/Makefile
+++ b/src/backend/utils/activity/Makefile
@@ -23,9 +23,10 @@ OBJS = \
        pgstat_function.o \
        pgstat_relation.o \
        pgstat_replslot.o \
+       pgstat_slru.o \
        pgstat_subscription.o \
        pgstat_wal.o \
-       pgstat_slru.o \
+       pgstat_xact.o \
        wait_event.o
 
 include $(top_srcdir)/src/backend/common.mk

diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
new file mode 100644 (file)
index 0000000..17907e3
--- /dev/null
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -0,0 +1,139 @@
+/* -------------------------------------------------------------------------
+ *
+ * pgstat_xact.c
+ *       Transactional integration for the cumulative statistics system.
+ *
+ * Copyright (c) 2001-2022, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *       src/backend/utils/activity/pgstat_xact.c
+ * -------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/transam.h"
+#include "access/xact.h"
+#include "pgstat.h"
+#include "utils/memutils.h"
+#include "utils/pgstat_internal.h"
+
+
+static PgStat_SubXactStatus *pgStatXactStack = NULL;
+
+
+/*
+ * Called from access/transam/xact.c at top-level transaction commit/abort.
+ */
+void
+AtEOXact_PgStat(bool isCommit, bool parallel)
+{
+       PgStat_SubXactStatus *xact_state;
+
+       AtEOXact_PgStat_Database(isCommit, parallel);
+
+       /* handle transactional stats information */
+       xact_state = pgStatXactStack;
+       if (xact_state != NULL)
+       {
+               Assert(xact_state->nest_level == 1);
+               Assert(xact_state->prev == NULL);
+
+               AtEOXact_PgStat_Relations(xact_state, isCommit);
+       }
+       pgStatXactStack = NULL;
+
+       /* Make sure any stats snapshot is thrown away */
+       pgstat_clear_snapshot();
+}
+
+/*
+ * Called from access/transam/xact.c at subtransaction commit/abort.
+ */
+void
+AtEOSubXact_PgStat(bool isCommit, int nestDepth)
+{
+       PgStat_SubXactStatus *xact_state;
+
+       /* merge the sub-transaction's transactional stats into the parent */
+       xact_state = pgStatXactStack;
+       if (xact_state != NULL &&
+               xact_state->nest_level >= nestDepth)
+       {
+               /* delink xact_state from stack immediately to simplify reuse case */
+               pgStatXactStack = xact_state->prev;
+
+               AtEOSubXact_PgStat_Relations(xact_state, isCommit, nestDepth);
+
+               pfree(xact_state);
+       }
+}
+
+/*
+ * Save the transactional stats state at 2PC transaction prepare.
+ */
+void
+AtPrepare_PgStat(void)
+{
+       PgStat_SubXactStatus *xact_state;
+
+       xact_state = pgStatXactStack;
+       if (xact_state != NULL)
+       {
+               Assert(xact_state->nest_level == 1);
+               Assert(xact_state->prev == NULL);
+
+               AtPrepare_PgStat_Relations(xact_state);
+       }
+}
+
+/*
+ * Clean up after successful PREPARE.
+ *
+ * Note: AtEOXact_PgStat is not called during PREPARE.
+ */
+void
+PostPrepare_PgStat(void)
+{
+       PgStat_SubXactStatus *xact_state;
+
+       /*
+        * We don't bother to free any of the transactional state, since it's all
+        * in TopTransactionContext and will go away anyway.
+        */
+       xact_state = pgStatXactStack;
+       if (xact_state != NULL)
+       {
+               Assert(xact_state->nest_level == 1);
+               Assert(xact_state->prev == NULL);
+
+               PostPrepare_PgStat_Relations(xact_state);
+       }
+       pgStatXactStack = NULL;
+
+       /* Make sure any stats snapshot is thrown away */
+       pgstat_clear_snapshot();
+}
+
+/*
+ * Ensure (sub)transaction stack entry for the given nest_level exists, adding
+ * it if needed.
+ */
+PgStat_SubXactStatus *
+pgstat_xact_stack_level_get(int nest_level)
+{
+       PgStat_SubXactStatus *xact_state;
+
+       xact_state = pgStatXactStack;
+       if (xact_state == NULL || xact_state->nest_level != nest_level)
+       {
+               xact_state = (PgStat_SubXactStatus *)
+                       MemoryContextAlloc(TopTransactionContext,
+                                                          sizeof(PgStat_SubXactStatus));
+               xact_state->nest_level = nest_level;
+               xact_state->prev = pgStatXactStack;
+               xact_state->first = NULL;
+               pgStatXactStack = xact_state;
+       }
+       return xact_state;
+}

diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 41fdf5f5a39e94a5c2aa0b6e9b1abc3977a2b0b9..95bf06f8291bac410d5e9225cda76593f1886160 100644 (file)
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -969,13 +969,6 @@ extern void PgstatCollectorMain(int argc, char *argv[]) pg_attribute_noreturn();
 /* Functions for backend initialization */
 extern void pgstat_initialize(void);
 
-/* transactional integration */
-extern void AtEOXact_PgStat(bool isCommit, bool parallel);
-extern void AtEOSubXact_PgStat(bool isCommit, int nestDepth);
-extern void AtPrepare_PgStat(void);
-extern void PostPrepare_PgStat(void);
-extern void pgstat_clear_snapshot(void);
-
 /* Functions called from backends */
 extern void pgstat_report_stat(bool force);
 extern void pgstat_vacuum_stat(void);
@@ -986,6 +979,7 @@ extern void pgstat_reset_single_counter(Oid objectid, PgStat_Single_Reset_Type t
 extern void pgstat_reset_shared_counters(const char *);
 
 /* stats accessors */
+extern void pgstat_clear_snapshot(void);
 extern PgStat_ArchiverStats *pgstat_fetch_stat_archiver(void);
 extern PgStat_BgWriterStats *pgstat_fetch_stat_bgwriter(void);
 extern PgStat_CheckpointerStats *pgstat_fetch_stat_checkpointer(void);
@@ -1157,6 +1151,16 @@ extern void pgstat_report_subscription_error(Oid subid, bool is_apply_error);
 extern void pgstat_report_subscription_drop(Oid subid);
 
 
+/*
+ * Functions in pgstat_xact.c
+ */
+
+extern void AtEOXact_PgStat(bool isCommit, bool parallel);
+extern void AtEOSubXact_PgStat(bool isCommit, int nestDepth);
+extern void AtPrepare_PgStat(void);
+extern void PostPrepare_PgStat(void);
+
+
 /*
  * Functions in pgstat_wal.c
  */

diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index abbb4f8d96492989d180d2b1e67c752764a690fb..6a828e3aa002d7418dfd94ca228b1b4ef9d0c69f 100644 (file)
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -77,7 +77,6 @@ static const char *const slru_names[] = {
  * Functions in pgstat.c
  */
 
-extern PgStat_SubXactStatus *pgstat_xact_stack_level_get(int nest_level);
 extern void pgstat_setheader(PgStat_MsgHdr *hdr, StatMsgType mtype);
 extern void pgstat_send(void *msg, int len);
 #ifdef USE_ASSERT_CHECKING
@@ -129,6 +128,13 @@ extern void pgstat_wal_initialize(void);
 extern bool pgstat_wal_pending(void);
 
 
+/*
+ * Functions in pgstat_xact.c
+ */
+
+extern PgStat_SubXactStatus *pgstat_xact_stack_level_get(int nest_level);
+
+
 /*
  * Variables in pgstat.c
  */