[PATCH v6 1/3] Add infrastructure for pg_system_versions view
Dmitry Dolgov <9erthalion6@gmail.com>
From: Dmitrii Dolgov <9erthalion6@gmail.com>
To:
Date: 2025-11-16T15:01:21Z
Lists: pgsql-hackers
Introduce a unified way of reporting versions (PostgreSQL itself, the
compiler, the host system, compile and runtime dependencies, etc.) via a
new system view pg_system_versions. This is going to be useful for
troubleshooting and should enhance bug reports, replacing manual
bug-prone collecting of the same information.
The view is backed by a hash table, that contains callbacks returning
version string for a particular component. The idea is to allow some
flexibility in reporting, making components responsible for how and when
the information is exposed.
---
doc/src/sgml/system-views.sgml | 65 +++++++++++++++
src/backend/catalog/system_views.sql | 8 ++
src/backend/utils/misc/Makefile | 3 +-
src/backend/utils/misc/meson.build | 1 +
src/backend/utils/misc/system_version.c | 105 ++++++++++++++++++++++++
src/include/catalog/pg_proc.dat | 6 ++
src/include/utils/system_version.h | 38 +++++++++
src/test/regress/expected/rules.out | 8 ++
src/tools/pgindent/typedefs.list | 2 +
9 files changed, 235 insertions(+), 1 deletion(-)
create mode 100644 src/backend/utils/misc/system_version.c
create mode 100644 src/include/utils/system_version.h
diff --git a/doc/src/sgml/system-views.sgml b/doc/src/sgml/system-views.sgml
index 7971498fe75..34f88c0b0d9 100644
--- a/doc/src/sgml/system-views.sgml
+++ b/doc/src/sgml/system-views.sgml
@@ -211,6 +211,11 @@
<entry>extended planner statistics for expressions</entry>
</row>
+ <row>
+ <entry><link linkend="view-pg-system-versions"><structname>pg_system_versions</structname></link></entry>
+ <entry>system versions</entry>
+ </row>
+
<row>
<entry><link linkend="view-pg-tables"><structname>pg_tables</structname></link></entry>
<entry>tables</entry>
@@ -4986,6 +4991,66 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
</sect1>
+ <sect1 id="view-pg-system-versions">
+ <title><structname>pg_system_versions</structname></title>
+
+ <indexterm zone="view-pg-system-versions">
+ <primary>pg_system_versions</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_system_versions</structname> provides description
+ about the versions of various system components, e.g. PostgreSQL itself,
+ the compiler used to build it, dependencies.
+ </para>
+
+ <table>
+ <title><structname>pg_system_versions</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>name</structfield> <type>text</type>
+ </para>
+ <para>
+ Component name
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>version</structfield> <type>text</type>
+ </para>
+ <para>
+ Component version
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>type</structfield> <type>text</type>
+ </para>
+ <para>
+ Component type (Compile Time or Run Time)
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+ </sect1>
+
<sect1 id="view-pg-tables">
<title><structname>pg_tables</structname></title>
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index 059e8778ca7..a00777e4f8b 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -1438,3 +1438,11 @@ REVOKE ALL ON pg_aios FROM PUBLIC;
GRANT SELECT ON pg_aios TO pg_read_all_stats;
REVOKE EXECUTE ON FUNCTION pg_get_aios() FROM PUBLIC;
GRANT EXECUTE ON FUNCTION pg_get_aios() TO pg_read_all_stats;
+
+CREATE VIEW pg_system_versions AS
+ SELECT
+ name, version,
+ CASE type WHEN 0 THEN 'Compile Time'
+ WHEN 1 THEN 'Run Time'
+ END AS "type"
+ FROM pg_get_system_versions();
diff --git a/src/backend/utils/misc/Makefile b/src/backend/utils/misc/Makefile
index f142d17178b..0ac5b3c79cd 100644
--- a/src/backend/utils/misc/Makefile
+++ b/src/backend/utils/misc/Makefile
@@ -32,7 +32,8 @@ OBJS = \
stack_depth.o \
superuser.o \
timeout.o \
- tzparser.o
+ tzparser.o \
+ system_version.o
# This location might depend on the installation directories. Therefore
# we can't substitute it into pg_config.h.
diff --git a/src/backend/utils/misc/meson.build b/src/backend/utils/misc/meson.build
index 9e389a00d05..5268eaa94c7 100644
--- a/src/backend/utils/misc/meson.build
+++ b/src/backend/utils/misc/meson.build
@@ -16,6 +16,7 @@ backend_sources += files(
'sampling.c',
'stack_depth.c',
'superuser.c',
+ 'system_version.c',
'timeout.c',
'tzparser.c',
)
diff --git a/src/backend/utils/misc/system_version.c b/src/backend/utils/misc/system_version.c
new file mode 100644
index 00000000000..f073f62ca75
--- /dev/null
+++ b/src/backend/utils/misc/system_version.c
@@ -0,0 +1,105 @@
+/*------------------------------------------------------------------------
+ *
+ * system_version.c
+ * Functions for reporting version of system components.
+ *
+ * A system component is defined very broadly here, it might be the PostgreSQL
+ * core itself, the compiler, the host system, any dependency that is used at
+ * compile time or run time.
+ *
+ * Version reporting is implemented via a hash table containing the component's
+ * name as a key and the callback to fetch the version string. Every component
+ * can register such a callback during initialization and is responsible for
+ * exposing its own information. The idea is that storing a callback instead of
+ * a version string directly allows for more flexibility about how and when the
+ * information could be reported.
+ *
+ * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ * src/backend/utils/misc/system_version.c
+ *
+ *------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "funcapi.h"
+#include "utils/builtins.h"
+#include "utils/system_version.h"
+
+static HTAB *versions = NULL;
+
+void
+add_system_version(const char *name, SystemVersionCB cb, VersionType type)
+{
+ SystemVersion *hentry;
+ const char *key;
+ bool found;
+
+ if (!versions)
+ {
+ HASHCTL ctl;
+
+ ctl.keysize = NAMEDATALEN;
+ ctl.entrysize = sizeof(SystemVersion);
+
+ versions = hash_create("System versions table",
+ MAX_SYSTEM_VERSIONS,
+ &ctl,
+ HASH_ELEM | HASH_STRINGS);
+ }
+
+ key = pstrdup(name);
+ Assert(strlen(key) < NAMEDATALEN);
+
+ hentry = (SystemVersion *) hash_search(versions, key,
+ HASH_ENTER, &found);
+
+ /* Duplicated entries are not expected */
+ Assert(!found);
+
+ hentry->callback = cb;
+ hentry->type = type;
+}
+
+/*
+ * pg_get_system_versions
+ *
+ * List information about system versions.
+ */
+Datum
+pg_get_system_versions(PG_FUNCTION_ARGS)
+{
+#define PG_GET_SYS_VERSIONS_COLS 3
+ ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+ HASH_SEQ_STATUS status;
+ SystemVersion *hentry;
+
+ /* Build tuplestore to hold the result rows */
+ InitMaterializedSRF(fcinfo, 0);
+
+ if (!versions)
+ return (Datum) 0;
+
+ hash_seq_init(&status, versions);
+ while ((hentry = (SystemVersion *) hash_seq_search(&status)) != NULL)
+ {
+ Datum values[PG_GET_SYS_VERSIONS_COLS] = {0};
+ bool nulls[PG_GET_SYS_VERSIONS_COLS] = {0};
+ bool available = false;
+ const char *version = hentry->callback(&available);
+
+ if (!available)
+ continue;
+
+ values[0] = CStringGetTextDatum(hentry->name);
+ values[1] = CStringGetTextDatum(version);
+ values[2] = Int32GetDatum(hentry->type);
+
+ tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
+ }
+
+ return (Datum) 0;
+}
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 5cf9e12fcb9..858e2f9983b 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -12604,4 +12604,10 @@
proargnames => '{pid,io_id,io_generation,state,operation,off,length,target,handle_data_len,raw_result,result,target_desc,f_sync,f_localmem,f_buffered}',
prosrc => 'pg_get_aios' },
+{ oid => '9432', descr => 'describe system verions',
+ proname => 'pg_get_system_versions', procost => '10', prorows => '10',
+ proretset => 't', provolatile => 'v', prorettype => 'record',
+ proargtypes => '', proallargtypes => '{text,text,int8}',
+ proargmodes => '{o,o,o}', proargnames => '{name,version,type}',
+ prosrc => 'pg_get_system_versions' },
]
diff --git a/src/include/utils/system_version.h b/src/include/utils/system_version.h
new file mode 100644
index 00000000000..18cb673d4ca
--- /dev/null
+++ b/src/include/utils/system_version.h
@@ -0,0 +1,38 @@
+/*-------------------------------------------------------------------------
+ * system_version.h
+ * Definitions related to system versions reporting
+ *
+ * Copyright (c) 2001-2024, PostgreSQL Global Development Group
+ *
+ * src/include/utils/system_version.h
+ * ----------
+ */
+
+#ifndef SYSTEM_VERSION_H
+#define SYSTEM_VERSION_H
+
+#define MAX_SYSTEM_VERSIONS 100
+
+typedef enum VersionType
+{
+ CompileTime,
+ RunTime,
+} VersionType;
+
+/*
+ * Callback to return version string of a system component.
+ * The version might be not available, what is indicated via the argument.
+ */
+typedef const char *(*SystemVersionCB) (bool *available);
+
+typedef struct SystemVersion
+{
+ char name[NAMEDATALEN]; /* Unique component name, used as a key
+ * for versions HTAB */
+ VersionType type;
+ SystemVersionCB callback; /* Callback to fetch the version string */
+} SystemVersion;
+
+void add_system_version(const char *name, SystemVersionCB cb, VersionType type);
+
+#endif /* SYSTEM_VERSION_H */
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index 7c52181cbcb..7db23198ff3 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -2683,6 +2683,14 @@ pg_stats_ext_exprs| SELECT cn.nspname AS schemaname,
JOIN LATERAL ( SELECT unnest(pg_get_statisticsobjdef_expressions(s.oid)) AS expr,
unnest(sd.stxdexpr) AS a) stat ON ((stat.expr IS NOT NULL)))
WHERE (pg_has_role(c.relowner, 'USAGE'::text) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
+pg_system_versions| SELECT name,
+ version,
+ CASE type
+ WHEN 0 THEN 'Compile Time'::text
+ WHEN 1 THEN 'Run Time'::text
+ ELSE NULL::text
+ END AS type
+ FROM pg_get_system_versions() pg_get_system_versions(name, version, type);
pg_tables| SELECT n.nspname AS schemaname,
c.relname AS tablename,
pg_get_userbyid(c.relowner) AS tableowner,
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 23bce72ae64..5ebb83d9899 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2934,6 +2934,7 @@ SysloggerStartupData
SystemRowsSamplerData
SystemSamplerData
SystemTimeSamplerData
+SystemVersion
TAPtype
TAR_MEMBER
TBMIterateResult
@@ -4215,6 +4216,7 @@ varattrib_1b_e
varattrib_4b
vbits
verifier_context
+VersionType
walrcv_alter_slot_fn
walrcv_check_conninfo_fn
walrcv_connect_fn
--
2.49.0
--2xvzvuagnffzv77q
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
filename="v6-0002-Add-core-versions-to-pg_system_versions.patch"