On Fri, Aug 25, 2023 at 08:32:51AM -0700, Nathan Bossart wrote:
> On second thought, renaming these exported functions so close to release is
> probably not a great idea. I should probably skip back-patching that one.
> Or I could have the existing functions call the new ones in v16 for
> backward compatibility...
Here is a new version of the patch that avoids changing the names of the
existing functions. I'm not thrilled about the name
(pgstat_fetch_stat_local_beentry_by_backend_id), so I am open to
suggestions. In any case, I'd like to rename all three of the
pgstat_fetch_stat_* functions in v17.
--
Nathan Bossart
Amazon Web Services: https://aws.amazon.com
>From e1ce8bf67f1b713294ef8d38dbee26bfc7ef16f4 Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nat...@postgresql.org>
Date: Thu, 24 Aug 2023 07:58:01 -0700
Subject: [PATCH v3 1/1] fix pg_stat_get_backend_subxact to use real backend id
---
src/backend/utils/activity/backend_status.c | 39 ++++++++++++++++-----
src/backend/utils/adt/pgstatfuncs.c | 2 +-
src/include/utils/backend_status.h | 1 +
3 files changed, 32 insertions(+), 10 deletions(-)
diff --git a/src/backend/utils/activity/backend_status.c b/src/backend/utils/activity/backend_status.c
index 38f91a495b..231cc5dd9a 100644
--- a/src/backend/utils/activity/backend_status.c
+++ b/src/backend/utils/activity/backend_status.c
@@ -1089,9 +1089,34 @@ cmp_lbestatus(const void *a, const void *b)
PgBackendStatus *
pgstat_fetch_stat_beentry(BackendId beid)
{
- LocalPgBackendStatus key;
LocalPgBackendStatus *ret;
+ ret = pgstat_fetch_stat_local_beentry_by_backend_id(beid);
+ if (ret)
+ return &ret->backendStatus;
+
+ return NULL;
+}
+
+
+/* ----------
+ * pgstat_fetch_stat_local_beentry_by_backend_id() -
+ *
+ * Like pgstat_fetch_stat_beentry() 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_fetch_stat_local_beentry()).
+ *
+ * NB: caller is responsible for checking if the user is permitted to see this
+ * info (especially the querystring).
+ * ----------
+ */
+LocalPgBackendStatus *
+pgstat_fetch_stat_local_beentry_by_backend_id(BackendId beid)
+{
+ LocalPgBackendStatus key;
+
pgstat_read_current_status();
/*
@@ -1099,14 +1124,10 @@ pgstat_fetch_stat_beentry(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 (LocalPgBackendStatus *) 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 2b9742ad21..68ae044399 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_fetch_stat_local_beentry(beid)) != NULL)
+ if ((local_beentry = pgstat_fetch_stat_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 77939a0aed..060431a39b 100644
--- a/src/include/utils/backend_status.h
+++ b/src/include/utils/backend_status.h
@@ -335,6 +335,7 @@ 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 LocalPgBackendStatus *pgstat_fetch_stat_local_beentry_by_backend_id(BackendId beid);
extern char *pgstat_clip_activity(const char *raw_activity);
--
2.25.1
