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-rw-r--r--src/backend/utils/activity/backend_status.c55
-rw-r--r--src/backend/utils/adt/pgstatfuncs.c48
-rw-r--r--src/include/utils/backend_status.h10
-rw-r--r--src/test/regress/expected/stats.out15
-rw-r--r--src/test/regress/sql/stats.sql10
5 files changed, 96 insertions, 42 deletions
diff --git a/src/backend/utils/activity/backend_status.c b/src/backend/utils/activity/backend_status.c
index c7ed1e6d7ac..1146a6c33cd 100644
--- a/src/backend/utils/activity/backend_status.c
+++ b/src/backend/utils/activity/backend_status.c
@@ -846,6 +846,13 @@ pgstat_read_current_status(void)
/* Only valid entries get included into the local array */
if (localentry->backendStatus.st_procpid > 0)
{
+ /*
+ * The BackendStatusArray index is exactly the BackendId of the
+ * source backend. Note that this means localBackendStatusTable
+ * is in order by backend_id. pgstat_fetch_stat_beentry() depends
+ * on that.
+ */
+ localentry->backend_id = i;
BackendIdGetTransactionIds(i,
&localentry->backend_xid,
&localentry->backend_xmin);
@@ -1045,26 +1052,57 @@ pgstat_get_my_query_id(void)
return MyBEEntry->st_query_id;
}
+/* ----------
+ * cmp_lbestatus
+ *
+ * Comparison function for bsearch() on an array of LocalPgBackendStatus.
+ * The backend_id field is used to compare the arguments.
+ * ----------
+ */
+static int
+cmp_lbestatus(const void *a, const void *b)
+{
+ const LocalPgBackendStatus *lbestatus1 = (const LocalPgBackendStatus *) a;
+ const LocalPgBackendStatus *lbestatus2 = (const LocalPgBackendStatus *) b;
+
+ return lbestatus1->backend_id - lbestatus2->backend_id;
+}
/* ----------
* pgstat_fetch_stat_beentry() -
*
* Support function for the SQL-callable pgstat* functions. Returns
- * our local copy of the current-activity entry for one backend.
+ * our local copy of the current-activity entry for one backend,
+ * or NULL if the given beid doesn't identify any known session.
+ *
+ * The beid argument is the BackendId of the desired session
+ * (note that this is unlike pgstat_fetch_stat_local_beentry()).
*
* NB: caller is responsible for a check if the user is permitted to see
* this info (especially the querystring).
* ----------
*/
PgBackendStatus *
-pgstat_fetch_stat_beentry(int beid)
+pgstat_fetch_stat_beentry(BackendId beid)
{
+ LocalPgBackendStatus key;
+ LocalPgBackendStatus *ret;
+
pgstat_read_current_status();
- if (beid < 1 || beid > localNumBackends)
- return NULL;
+ /*
+ * Since the localBackendStatusTable is in order by backend_id, we can use
+ * bsearch() to search it efficiently.
+ */
+ key.backend_id = beid;
+ ret = (LocalPgBackendStatus *) bsearch(&key, localBackendStatusTable,
+ localNumBackends,
+ sizeof(LocalPgBackendStatus),
+ cmp_lbestatus);
+ if (ret)
+ return &ret->backendStatus;
- return &localBackendStatusTable[beid - 1].backendStatus;
+ return NULL;
}
@@ -1074,6 +1112,10 @@ pgstat_fetch_stat_beentry(int beid)
* Like pgstat_fetch_stat_beentry() but with locally computed additions (like
* xid and xmin values of the backend)
*
+ * The beid argument is a 1-based index in the localBackendStatusTable
+ * (note that this is unlike pgstat_fetch_stat_beentry()).
+ * Returns NULL if the argument is out of range (no current caller does that).
+ *
* NB: caller is responsible for a check if the user is permitted to see
* this info (especially the querystring).
* ----------
@@ -1094,7 +1136,8 @@ pgstat_fetch_stat_local_beentry(int beid)
* pgstat_fetch_stat_numbackends() -
*
* Support function for the SQL-callable pgstat* functions. Returns
- * the maximum current backend id.
+ * the number of sessions known in the localBackendStatusTable, i.e.
+ * the maximum 1-based index to pass to pgstat_fetch_stat_local_beentry().
* ----------
*/
int
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index be15b4b2e57..eadd8464ff2 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -415,7 +415,6 @@ pg_stat_get_backend_idset(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
int *fctx;
- int32 result;
/* stuff done only on the first call of the function */
if (SRF_IS_FIRSTCALL())
@@ -424,11 +423,10 @@ pg_stat_get_backend_idset(PG_FUNCTION_ARGS)
funcctx = SRF_FIRSTCALL_INIT();
fctx = MemoryContextAlloc(funcctx->multi_call_memory_ctx,
- 2 * sizeof(int));
+ sizeof(int));
funcctx->user_fctx = fctx;
fctx[0] = 0;
- fctx[1] = pgstat_fetch_stat_numbackends();
}
/* stuff done on every call of the function */
@@ -436,12 +434,22 @@ pg_stat_get_backend_idset(PG_FUNCTION_ARGS)
fctx = funcctx->user_fctx;
fctx[0] += 1;
- result = fctx[0];
- if (result <= fctx[1])
+ /*
+ * We recheck pgstat_fetch_stat_numbackends() each time through, just in
+ * case the local status data has been refreshed since we started. It's
+ * plenty cheap enough if not. If a refresh does happen, we'll likely
+ * miss or duplicate some backend IDs, but we're content not to crash.
+ * (Refreshing midway through such a query would be problematic usage
+ * anyway, since the backend IDs we've already returned might no longer
+ * refer to extant sessions.)
+ */
+ if (fctx[0] <= pgstat_fetch_stat_numbackends())
{
/* do when there is more left to send */
- SRF_RETURN_NEXT(funcctx, Int32GetDatum(result));
+ LocalPgBackendStatus *local_beentry = pgstat_fetch_stat_local_beentry(fctx[0]);
+
+ SRF_RETURN_NEXT(funcctx, Int32GetDatum(local_beentry->backend_id));
}
else
{
@@ -493,17 +501,13 @@ pg_stat_get_progress_info(PG_FUNCTION_ARGS)
int i;
local_beentry = pgstat_fetch_stat_local_beentry(curr_backend);
-
- if (!local_beentry)
- continue;
-
beentry = &local_beentry->backendStatus;
/*
* Report values for only those backends which are running the given
* command.
*/
- if (!beentry || beentry->st_progress_command != cmdtype)
+ if (beentry->st_progress_command != cmdtype)
continue;
/* Value available to all callers */
@@ -558,24 +562,6 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
/* Get the next one in the list */
local_beentry = pgstat_fetch_stat_local_beentry(curr_backend);
- if (!local_beentry)
- {
- int i;
-
- /* Ignore missing entries if looking for specific PID */
- if (pid != -1)
- continue;
-
- for (i = 0; i < lengthof(nulls); i++)
- nulls[i] = true;
-
- nulls[5] = false;
- values[5] = CStringGetTextDatum("<backend information not available>");
-
- tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
- continue;
- }
-
beentry = &local_beentry->backendStatus;
/* If looking for specific PID, ignore all the others */
@@ -1180,9 +1166,9 @@ pg_stat_get_db_numbackends(PG_FUNCTION_ARGS)
result = 0;
for (beid = 1; beid <= tot_backends; beid++)
{
- PgBackendStatus *beentry = pgstat_fetch_stat_beentry(beid);
+ LocalPgBackendStatus *local_beentry = pgstat_fetch_stat_local_beentry(beid);
- if (beentry && beentry->st_databaseid == dbid)
+ if (local_beentry->backendStatus.st_databaseid == dbid)
result++;
}
diff --git a/src/include/utils/backend_status.h b/src/include/utils/backend_status.h
index 7403bca25ed..b582b46e9f9 100644
--- a/src/include/utils/backend_status.h
+++ b/src/include/utils/backend_status.h
@@ -13,6 +13,7 @@
#include "datatype/timestamp.h"
#include "libpq/pqcomm.h"
#include "miscadmin.h" /* for BackendType */
+#include "storage/backendid.h"
#include "utils/backend_progress.h"
@@ -248,6 +249,13 @@ typedef struct LocalPgBackendStatus
PgBackendStatus backendStatus;
/*
+ * The backend ID. For auxiliary processes, this will be set to a value
+ * greater than MaxBackends (since auxiliary processes do not have proper
+ * backend IDs).
+ */
+ BackendId backend_id;
+
+ /*
* The xid of the current transaction if available, InvalidTransactionId
* if not.
*/
@@ -313,7 +321,7 @@ extern uint64 pgstat_get_my_query_id(void);
* ----------
*/
extern int pgstat_fetch_stat_numbackends(void);
-extern PgBackendStatus *pgstat_fetch_stat_beentry(int beid);
+extern PgBackendStatus *pgstat_fetch_stat_beentry(BackendId beid);
extern LocalPgBackendStatus *pgstat_fetch_stat_local_beentry(int beid);
extern char *pgstat_clip_activity(const char *raw_activity);
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 6a10dc462bd..f701da20697 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -576,9 +576,9 @@ SELECT sessions > :db_stat_sessions FROM pg_stat_database WHERE datname = (SELEC
-- Test pg_stat_bgwriter checkpointer-related stats, together with pg_stat_wal
SELECT checkpoints_req AS rqst_ckpts_before FROM pg_stat_bgwriter \gset
--- Test pg_stat_wal
+-- Test pg_stat_wal (and make a temp table so our temp schema exists)
SELECT wal_bytes AS wal_bytes_before FROM pg_stat_wal \gset
-CREATE TABLE test_stats_temp AS SELECT 17;
+CREATE TEMP TABLE test_stats_temp AS SELECT 17;
DROP TABLE test_stats_temp;
-- Checkpoint twice: The checkpointer reports stats after reporting completion
-- of the checkpoint. But after a second checkpoint we'll see at least the
@@ -597,6 +597,17 @@ SELECT wal_bytes > :wal_bytes_before FROM pg_stat_wal;
t
(1 row)
+-- Test pg_stat_get_backend_idset() and some allied functions.
+-- In particular, verify that their notion of backend ID matches
+-- our temp schema index.
+SELECT (current_schemas(true))[1] = ('pg_temp_' || beid::text) AS match
+FROM pg_stat_get_backend_idset() beid
+WHERE pg_stat_get_backend_pid(beid) = pg_backend_pid();
+ match
+-------
+ t
+(1 row)
+
-----
-- Test that resetting stats works for reset timestamp
-----
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index a6b0e9e0428..eb081f65a42 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -303,10 +303,10 @@ SELECT sessions > :db_stat_sessions FROM pg_stat_database WHERE datname = (SELEC
-- Test pg_stat_bgwriter checkpointer-related stats, together with pg_stat_wal
SELECT checkpoints_req AS rqst_ckpts_before FROM pg_stat_bgwriter \gset
--- Test pg_stat_wal
+-- Test pg_stat_wal (and make a temp table so our temp schema exists)
SELECT wal_bytes AS wal_bytes_before FROM pg_stat_wal \gset
-CREATE TABLE test_stats_temp AS SELECT 17;
+CREATE TEMP TABLE test_stats_temp AS SELECT 17;
DROP TABLE test_stats_temp;
-- Checkpoint twice: The checkpointer reports stats after reporting completion
@@ -318,6 +318,12 @@ CHECKPOINT;
SELECT checkpoints_req > :rqst_ckpts_before FROM pg_stat_bgwriter;
SELECT wal_bytes > :wal_bytes_before FROM pg_stat_wal;
+-- Test pg_stat_get_backend_idset() and some allied functions.
+-- In particular, verify that their notion of backend ID matches
+-- our temp schema index.
+SELECT (current_schemas(true))[1] = ('pg_temp_' || beid::text) AS match
+FROM pg_stat_get_backend_idset() beid
+WHERE pg_stat_get_backend_pid(beid) = pg_backend_pid();
-----
-- Test that resetting stats works for reset timestamp
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-31 11:04:51 +0000