On Wed, Aug 23, 2023 at 07:51:40PM -0700, Nathan Bossart wrote:
> On Wed, Aug 23, 2023 at 07:32:06PM -0700, Nathan Bossart wrote:
>> On Thu, Aug 24, 2023 at 10:22:49AM +0900, Ian Lawrence Barwick wrote:
>>> Looking at the code, this is happening because
>>> "pgstat_fetch_stat_local_beentry()"
>>> expects to be passed the backend ID as an integer representing a 1-based
>>> index
>>> referring to "localBackendStatusTable", but "pg_stat_get_backend_subxact()"
>>> is presumably intended to take the actual BackendId , as per other
>>> "pg_stat_get_XXX()"
>>> functions.
>>
>> Yes, this was changed in d7e39d7, but 10ea0f9 seems to have missed the
>> memo.
>
> BTW I'd argue that this is a bug in v16 that we should try to fix before
> GA, so I've added an open item [0]. I assigned it to Robert (CC'd) since
> he was the committer, but I'm happy to pick it up.
Since RC1 is fast approaching, I put together a revised patch set. 0001
renames the existing pgstat_fetch_stat* functions, and 0002 adds
pgstat_get_local_beentry_by_backend_id() and uses it for
pg_stat_get_backend_subxact(). Thoughts?
--
Nathan Bossart
Amazon Web Services: https://aws.amazon.com
>From 3af12242ec10abe83d195e4b3f0765afec40f710 Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nat...@postgresql.org>
Date: Thu, 24 Aug 2023 07:42:54 -0700
Subject: [PATCH v2 1/2] rename some pgstat functions
---
src/backend/utils/activity/backend_status.c | 22 +++++++-------
src/backend/utils/adt/pgstatfuncs.c | 32 ++++++++++-----------
src/include/utils/backend_status.h | 4 +--
3 files changed, 29 insertions(+), 29 deletions(-)
diff --git a/src/backend/utils/activity/backend_status.c b/src/backend/utils/activity/backend_status.c
index 38f91a495b..aea05a9014 100644
--- a/src/backend/utils/activity/backend_status.c
+++ b/src/backend/utils/activity/backend_status.c
@@ -849,8 +849,8 @@ pgstat_read_current_status(void)
/*
* 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.
+ * is in order by backend_id. pgstat_get_beentry_by_backend_id()
+ * depends on that.
*/
localentry->backend_id = i;
BackendIdGetTransactionIds(i,
@@ -1073,21 +1073,21 @@ cmp_lbestatus(const void *a, const void *b)
}
/* ----------
- * pgstat_fetch_stat_beentry() -
+ * pgstat_get_beentry_by_backend_id() -
*
* Support function for the SQL-callable pgstat* functions. Returns
* 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()).
+ * (note that this is unlike pgstat_get_local_beentry_by_index()).
*
* NB: caller is responsible for a check if the user is permitted to see
* this info (especially the querystring).
* ----------
*/
PgBackendStatus *
-pgstat_fetch_stat_beentry(BackendId beid)
+pgstat_get_beentry_by_backend_id(BackendId beid)
{
LocalPgBackendStatus key;
LocalPgBackendStatus *ret;
@@ -1111,13 +1111,13 @@ pgstat_fetch_stat_beentry(BackendId beid)
/* ----------
- * pgstat_fetch_stat_local_beentry() -
+ * pgstat_get_local_beentry_by_index() -
*
- * Like pgstat_fetch_stat_beentry() but with locally computed additions (like
- * xid and xmin values of the backend)
+ * Like pgstat_get_beentry_by_backend_id() 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()).
+ * (note that this is unlike pgstat_get_beentry_by_backend_id()).
* 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
@@ -1125,7 +1125,7 @@ pgstat_fetch_stat_beentry(BackendId beid)
* ----------
*/
LocalPgBackendStatus *
-pgstat_fetch_stat_local_beentry(int beid)
+pgstat_get_local_beentry_by_index(int beid)
{
pgstat_read_current_status();
@@ -1141,7 +1141,7 @@ pgstat_fetch_stat_local_beentry(int beid)
*
* Support function for the SQL-callable pgstat* functions. Returns
* the number of sessions known in the localBackendStatusTable, i.e.
- * the maximum 1-based index to pass to pgstat_fetch_stat_local_beentry().
+ * the maximum 1-based index to pass to pgstat_get_local_beentry_by_index().
* ----------
*/
int
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 2b9742ad21..7deefed5ab 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -211,7 +211,7 @@ pg_stat_get_backend_idset(PG_FUNCTION_ARGS)
if (fctx[0] <= pgstat_fetch_stat_numbackends())
{
/* do when there is more left to send */
- LocalPgBackendStatus *local_beentry = pgstat_fetch_stat_local_beentry(fctx[0]);
+ LocalPgBackendStatus *local_beentry = pgstat_get_local_beentry_by_index(fctx[0]);
SRF_RETURN_NEXT(funcctx, Int32GetDatum(local_beentry->backend_id));
}
@@ -264,7 +264,7 @@ pg_stat_get_progress_info(PG_FUNCTION_ARGS)
bool nulls[PG_STAT_GET_PROGRESS_COLS] = {0};
int i;
- local_beentry = pgstat_fetch_stat_local_beentry(curr_backend);
+ local_beentry = pgstat_get_local_beentry_by_index(curr_backend);
beentry = &local_beentry->backendStatus;
/*
@@ -325,7 +325,7 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
const char *wait_event = NULL;
/* Get the next one in the list */
- local_beentry = pgstat_fetch_stat_local_beentry(curr_backend);
+ local_beentry = pgstat_get_local_beentry_by_index(curr_backend);
beentry = &local_beentry->backendStatus;
/* If looking for specific PID, ignore all the others */
@@ -672,7 +672,7 @@ pg_stat_get_backend_pid(PG_FUNCTION_ARGS)
int32 beid = PG_GETARG_INT32(0);
PgBackendStatus *beentry;
- if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
+ if ((beentry = pgstat_get_beentry_by_backend_id(beid)) == NULL)
PG_RETURN_NULL();
PG_RETURN_INT32(beentry->st_procpid);
@@ -685,7 +685,7 @@ pg_stat_get_backend_dbid(PG_FUNCTION_ARGS)
int32 beid = PG_GETARG_INT32(0);
PgBackendStatus *beentry;
- if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
+ if ((beentry = pgstat_get_beentry_by_backend_id(beid)) == NULL)
PG_RETURN_NULL();
PG_RETURN_OID(beentry->st_databaseid);
@@ -698,7 +698,7 @@ pg_stat_get_backend_userid(PG_FUNCTION_ARGS)
int32 beid = PG_GETARG_INT32(0);
PgBackendStatus *beentry;
- if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
+ if ((beentry = pgstat_get_beentry_by_backend_id(beid)) == NULL)
PG_RETURN_NULL();
PG_RETURN_OID(beentry->st_userid);
@@ -727,7 +727,7 @@ pg_stat_get_backend_subxact(PG_FUNCTION_ARGS)
BlessTupleDesc(tupdesc);
- if ((local_beentry = pgstat_fetch_stat_local_beentry(beid)) != NULL)
+ if ((local_beentry = pgstat_get_local_beentry_by_index(beid)) != NULL)
{
/* Fill values and NULLs */
values[0] = Int32GetDatum(local_beentry->backend_subxact_count);
@@ -752,7 +752,7 @@ pg_stat_get_backend_activity(PG_FUNCTION_ARGS)
char *clipped_activity;
text *ret;
- if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
+ if ((beentry = pgstat_get_beentry_by_backend_id(beid)) == NULL)
activity = "<backend information not available>";
else if (!HAS_PGSTAT_PERMISSIONS(beentry->st_userid))
activity = "<insufficient privilege>";
@@ -776,7 +776,7 @@ pg_stat_get_backend_wait_event_type(PG_FUNCTION_ARGS)
PGPROC *proc;
const char *wait_event_type = NULL;
- if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
+ if ((beentry = pgstat_get_beentry_by_backend_id(beid)) == NULL)
wait_event_type = "<backend information not available>";
else if (!HAS_PGSTAT_PERMISSIONS(beentry->st_userid))
wait_event_type = "<insufficient privilege>";
@@ -797,7 +797,7 @@ pg_stat_get_backend_wait_event(PG_FUNCTION_ARGS)
PGPROC *proc;
const char *wait_event = NULL;
- if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
+ if ((beentry = pgstat_get_beentry_by_backend_id(beid)) == NULL)
wait_event = "<backend information not available>";
else if (!HAS_PGSTAT_PERMISSIONS(beentry->st_userid))
wait_event = "<insufficient privilege>";
@@ -818,7 +818,7 @@ pg_stat_get_backend_activity_start(PG_FUNCTION_ARGS)
TimestampTz result;
PgBackendStatus *beentry;
- if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
+ if ((beentry = pgstat_get_beentry_by_backend_id(beid)) == NULL)
PG_RETURN_NULL();
else if (!HAS_PGSTAT_PERMISSIONS(beentry->st_userid))
@@ -844,7 +844,7 @@ pg_stat_get_backend_xact_start(PG_FUNCTION_ARGS)
TimestampTz result;
PgBackendStatus *beentry;
- if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
+ if ((beentry = pgstat_get_beentry_by_backend_id(beid)) == NULL)
PG_RETURN_NULL();
else if (!HAS_PGSTAT_PERMISSIONS(beentry->st_userid))
@@ -866,7 +866,7 @@ pg_stat_get_backend_start(PG_FUNCTION_ARGS)
TimestampTz result;
PgBackendStatus *beentry;
- if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
+ if ((beentry = pgstat_get_beentry_by_backend_id(beid)) == NULL)
PG_RETURN_NULL();
else if (!HAS_PGSTAT_PERMISSIONS(beentry->st_userid))
@@ -890,7 +890,7 @@ pg_stat_get_backend_client_addr(PG_FUNCTION_ARGS)
char remote_host[NI_MAXHOST];
int ret;
- if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
+ if ((beentry = pgstat_get_beentry_by_backend_id(beid)) == NULL)
PG_RETURN_NULL();
else if (!HAS_PGSTAT_PERMISSIONS(beentry->st_userid))
@@ -935,7 +935,7 @@ pg_stat_get_backend_client_port(PG_FUNCTION_ARGS)
char remote_port[NI_MAXSERV];
int ret;
- if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
+ if ((beentry = pgstat_get_beentry_by_backend_id(beid)) == NULL)
PG_RETURN_NULL();
else if (!HAS_PGSTAT_PERMISSIONS(beentry->st_userid))
@@ -983,7 +983,7 @@ pg_stat_get_db_numbackends(PG_FUNCTION_ARGS)
result = 0;
for (beid = 1; beid <= tot_backends; beid++)
{
- LocalPgBackendStatus *local_beentry = pgstat_fetch_stat_local_beentry(beid);
+ LocalPgBackendStatus *local_beentry = pgstat_get_local_beentry_by_index(beid);
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 77939a0aed..e53098ec9e 100644
--- a/src/include/utils/backend_status.h
+++ b/src/include/utils/backend_status.h
@@ -333,8 +333,8 @@ extern uint64 pgstat_get_my_query_id(void);
* ----------
*/
extern int pgstat_fetch_stat_numbackends(void);
-extern PgBackendStatus *pgstat_fetch_stat_beentry(BackendId beid);
-extern LocalPgBackendStatus *pgstat_fetch_stat_local_beentry(int beid);
+extern PgBackendStatus *pgstat_get_beentry_by_backend_id(BackendId beid);
+extern LocalPgBackendStatus *pgstat_get_local_beentry_by_index(int beid);
extern char *pgstat_clip_activity(const char *raw_activity);
--
2.25.1
>From 82d95d01526d09c565413696a366b350a9f796ff Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nat...@postgresql.org>
Date: Thu, 24 Aug 2023 07:58:01 -0700
Subject: [PATCH v2 2/2] fix pg_stat_get_backend_subxact to use real backend id
---
src/backend/utils/activity/backend_status.c | 36 +++++++++++++++------
src/backend/utils/adt/pgstatfuncs.c | 2 +-
src/include/utils/backend_status.h | 1 +
3 files changed, 29 insertions(+), 10 deletions(-)
diff --git a/src/backend/utils/activity/backend_status.c b/src/backend/utils/activity/backend_status.c
index aea05a9014..d5babd9fb0 100644
--- a/src/backend/utils/activity/backend_status.c
+++ b/src/backend/utils/activity/backend_status.c
@@ -1088,9 +1088,33 @@ cmp_lbestatus(const void *a, const void *b)
*/
PgBackendStatus *
pgstat_get_beentry_by_backend_id(BackendId beid)
+{
+ LocalPgBackendStatus *ret = pgstat_get_local_beentry_by_backend_id(beid);
+
+ if (ret)
+ return &ret->backendStatus;
+
+ return NULL;
+}
+
+
+/* ----------
+ * pgstat_get_local_beentry_by_backend_id() -
+ *
+ * Like pgstat_get_beentry_by_backend_id() but with locally computed additions
+ * (like xid and xmin values of the backend)
+ *
+ * The beid argument is the BackendId of the desired session
+ * (note that this is unlike pgstat_get_local_beentry_by_index()).
+ *
+ * NB: caller is responsible for checking if the user is permitted to see this
+ * info (especially the querystring).
+ * ----------
+ */
+LocalPgBackendStatus *
+pgstat_get_local_beentry_by_backend_id(BackendId beid)
{
LocalPgBackendStatus key;
- LocalPgBackendStatus *ret;
pgstat_read_current_status();
@@ -1099,14 +1123,8 @@ pgstat_get_beentry_by_backend_id(BackendId beid)
* 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 NULL;
+ return bsearch(&key, localBackendStatusTable, localNumBackends,
+ sizeof(LocalPgBackendStatus), cmp_lbestatus);
}
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 7deefed5ab..62d327bb92 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -727,7 +727,7 @@ pg_stat_get_backend_subxact(PG_FUNCTION_ARGS)
BlessTupleDesc(tupdesc);
- if ((local_beentry = pgstat_get_local_beentry_by_index(beid)) != NULL)
+ if ((local_beentry = pgstat_get_local_beentry_by_backend_id(beid)) != NULL)
{
/* Fill values and NULLs */
values[0] = Int32GetDatum(local_beentry->backend_subxact_count);
diff --git a/src/include/utils/backend_status.h b/src/include/utils/backend_status.h
index e53098ec9e..a996c7fd23 100644
--- a/src/include/utils/backend_status.h
+++ b/src/include/utils/backend_status.h
@@ -334,6 +334,7 @@ extern uint64 pgstat_get_my_query_id(void);
*/
extern int pgstat_fetch_stat_numbackends(void);
extern PgBackendStatus *pgstat_get_beentry_by_backend_id(BackendId beid);
+extern LocalPgBackendStatus *pgstat_get_local_beentry_by_backend_id(BackendId beid);
extern LocalPgBackendStatus *pgstat_get_local_beentry_by_index(int beid);
extern char *pgstat_clip_activity(const char *raw_activity);
--
2.25.1
