> On Tue, Apr 01, 2025 at 09:27:23PM +0200, Dmitry Dolgov wrote:
> > On Sun, Mar 23, 2025 at 06:21:33PM GMT, Tom Lane wrote:
> >
> > FWIW, I think the 0004 patch is about to be mostly obsoleted by
> > Andrei's proposal at [1].  To the extent that it's not obsoleted,
> > I question whether it's something we want at all, given the ground
> > rule that unprivileged users are not supposed to have access to info
> > about the server's filesystem.
> 
> To be clear -- I don't have a case for 0004 myself, except some vague
> expectation that in certain situations it could be useful to know which
> shared objects are loaded, even if they are not Postgres modules. Based
> on the feedback from the original thread [2], there were couple similar
> opinions, maybe folks could reply here whether [1] would be sufficient
> for them.

Better late than never, rebased and dropped 0004.
>From efae8acde7be2a504dbcccfc43f7994c94753c23 Mon Sep 17 00:00:00 2001
From: Dmitrii Dolgov <[email protected]>
Date: Sun, 16 Nov 2025 16:01:21 +0100
Subject: [PATCH v4 1/3] Add infrastructure for pg_system_versions view

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 | 106 ++++++++++++++++++++++++
 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, 236 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..cb7b57e0102 100644
--- a/doc/src/sgml/system-views.sgml
+++ b/doc/src/sgml/system-views.sgml
@@ -246,6 +246,11 @@
       <entry>wait events</entry>
      </row>
 
+     <row>
+      <entry><link 
linkend="view-pg-system-versions"><structname>pg_system_versions</structname></link></entry>
+      <entry>system versions</entry>
+     </row>
+
     </tbody>
    </tgroup>
   </table>
@@ -5611,4 +5616,64 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
   </table>
  </sect1>
 
+ <sect1 id="view-pg-system-versions">
+  <title><structname>pg_system_versions</structname></title>
+
+  <indexterm zone="view-pg-system-version">
+   <primary>pg_system_versions</primary>
+  </indexterm>
+
+  <para>
+   The view <structname>pg_system_versions</structname> provides description
+   about versions of various system components, e.g. PostgreSQL itself,
+   compiler used to build it, dependencies, etc.
+  </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>
+
 </chapter>
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..4d15ce58bf9
--- /dev/null
+++ b/src/backend/utils/misc/system_version.c
@@ -0,0 +1,106 @@
+/*------------------------------------------------------------------------
+ *
+ * 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 <unicode/uchar.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);
+               ctl.hcxt = CurrentMemoryContext;
+
+               versions = hash_create("System versions table",
+                                                          MAX_SYSTEM_VERSIONS,
+                                                          &ctl,
+                                                          HASH_ELEM | 
HASH_STRINGS);
+       }
+
+       key = pstrdup(name);
+       hentry = (SystemVersion *) hash_search(versions, key,
+                                                                               
   HASH_ENTER, &found);
+
+       if (found)
+               elog(ERROR, "duplicated system version");
+
+       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] = 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

>From 71113edfe4e9571e2bf0fe59554913331560754d Mon Sep 17 00:00:00 2001
From: Dmitrii Dolgov <[email protected]>
Date: Sun, 16 Nov 2025 17:30:59 +0100
Subject: [PATCH v4 2/3] Add core versions to pg_system_versions

Populate pg_system_versions with a set of core versions: host system
architecture, ICU version, glibc version, PostgreSQL itself and compiler
which was used to build everything. Register the core versions at the
backend startup.

    select * from pg_system_versions;
       name   |   version    |     type
    ----------+--------------+--------------
     Arch     | x86_64-linux | Compile Time
     ICU      | 15.1         | Run Time
     Core     | 18devel      | Compile Time
     Compiler | gcc-14.0.1   | Compile Time
     Glibc    | 2.40         | Run Time
---
 configure                               | 12 +++++
 configure.ac                            |  4 ++
 meson.build                             |  4 ++
 src/backend/tcop/postgres.c             | 12 +++++
 src/backend/utils/misc/system_version.c | 59 +++++++++++++++++++++++++
 src/include/pg_config.h.in              |  4 ++
 src/include/utils/system_version.h      | 12 +++++
 src/test/regress/expected/sysviews.out  |  9 ++++
 src/test/regress/sql/sysviews.sql       |  5 +++
 9 files changed, 121 insertions(+)

diff --git a/configure b/configure
index 3a0ed11fa8e..f7d5f695679 100755
--- a/configure
+++ b/configure
@@ -19293,6 +19293,18 @@ else
 fi
 
 
+cat >>confdefs.h <<_ACEOF
+#define PG_CC_STR "$cc_string"
+_ACEOF
+
+
+
+cat >>confdefs.h <<_ACEOF
+#define PG_ARCH_STR "$host"
+_ACEOF
+
+
+
 cat >>confdefs.h <<_ACEOF
 #define PG_VERSION_STR "PostgreSQL $PG_VERSION on $host, compiled by 
$cc_string, `expr $ac_cv_sizeof_void_p \* 8`-bit"
 _ACEOF
diff --git a/configure.ac b/configure.ac
index c2413720a18..9f7f7f75535 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2448,6 +2448,10 @@ else
   cc_string=$CC
 fi
 
+AC_DEFINE_UNQUOTED(PG_CC_STR, ["$cc_string"], [C compiler version])
+
+AC_DEFINE_UNQUOTED(PG_ARCH_STR, ["$host"], [Platform])
+
 AC_DEFINE_UNQUOTED(PG_VERSION_STR,
                    ["PostgreSQL $PG_VERSION on $host, compiled by $cc_string, 
`expr $ac_cv_sizeof_void_p \* 8`-bit"],
                    [A string containing the version number, platform, and C 
compiler])
diff --git a/meson.build b/meson.build
index c1e17aa3040..2265eaafb48 100644
--- a/meson.build
+++ b/meson.build
@@ -2972,6 +2972,10 @@ 
cdata.set('USE_@0@_SEMAPHORES'.format(sema_kind.to_upper()), 1)
 cdata.set('MEMSET_LOOP_LIMIT', memset_loop_limit)
 cdata.set_quoted('DLSUFFIX', dlsuffix)
 
+cdata.set_quoted('PG_CC_STR', '@0@-@1@'.format(cc.get_id(), cc.version()))
+
+cdata.set_quoted('PG_ARCH_STR', '@0@-@1@'.format(
+  host_machine.cpu_family(), host_system))
 
 # built later than the rest of the version metadata, we need SIZEOF_VOID_P
 cdata.set_quoted('PG_VERSION_STR',
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 7dd75a490aa..3a8ff419425 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -81,6 +81,7 @@
 #include "utils/timeout.h"
 #include "utils/timestamp.h"
 #include "utils/varlena.h"
+#include "utils/system_version.h"
 
 /* ----------------
  *             global variables
@@ -186,6 +187,7 @@ static void drop_unnamed_stmt(void);
 static void log_disconnections(int code, Datum arg);
 static void enable_statement_timeout(void);
 static void disable_statement_timeout(void);
+static void register_system_versions(void);
 
 
 /* ----------------------------------------------------------------
@@ -4318,6 +4320,9 @@ PostgresMain(const char *dbname, const char *username)
         */
        BeginReportingGUCOptions();
 
+       /* Prepare information for reporting versions and libraries. */
+       register_system_versions();
+
        /*
         * Also set up handler to log session end; we have to wait till now to 
be
         * sure Log_disconnections has its final value.
@@ -5237,3 +5242,10 @@ disable_statement_timeout(void)
        if (get_timeout_active(STATEMENT_TIMEOUT))
                disable_timeout(STATEMENT_TIMEOUT, false);
 }
+
+static void
+register_system_versions()
+{
+       /* Set up reporting of core versions. */
+       register_core_versions();
+}
diff --git a/src/backend/utils/misc/system_version.c 
b/src/backend/utils/misc/system_version.c
index 4d15ce58bf9..6d86b90d79c 100644
--- a/src/backend/utils/misc/system_version.c
+++ b/src/backend/utils/misc/system_version.c
@@ -65,6 +65,65 @@ add_system_version(const char *name, SystemVersionCB cb, 
VersionType type)
        hentry->type = type;
 }
 
+/*
+ * Register versions that describe core components and do not correspond to any
+ * individual component.
+ */
+void
+register_core_versions()
+{
+       add_system_version("Core", core_get_version, CompileTime);
+       add_system_version("Arch", core_get_arch, CompileTime);
+       add_system_version("Compiler", core_get_compiler, CompileTime);
+       add_system_version("ICU", icu_get_version, RunTime);
+       add_system_version("Glibc", glibc_get_version, RunTime);
+}
+
+const char *
+core_get_version(bool *available)
+{
+       *available = true;
+       return (const char *) psprintf("%s", PG_VERSION);
+}
+
+const char *
+core_get_arch(bool *available)
+{
+       *available = true;
+       return (const char *) psprintf("%s", PG_ARCH_STR);
+}
+
+const char *
+core_get_compiler(bool *available)
+{
+       *available = true;
+       return (const char *) psprintf("%s", PG_CC_STR);
+}
+
+const char *
+icu_get_version(bool *available)
+{
+#ifdef USE_ICU
+       UVersionInfo UCDVersion;
+       char       *version = palloc0(U_MAX_VERSION_STRING_LENGTH);
+
+       *available = true;
+       u_getUnicodeVersion(UCDVersion);
+       u_versionToString(UCDVersion, version);
+       return (const char *) version;
+#else
+       *available = false;
+       return (const char *) "";
+#endif
+}
+
+const char *
+glibc_get_version(bool *available)
+{
+       *available = true;
+       return (const char *) gnu_get_libc_version();
+}
+
 /*
  * pg_get_system_versions
  *
diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in
index b0b0cfdaf79..dacf496ce71 100644
--- a/src/include/pg_config.h.in
+++ b/src/include/pg_config.h.in
@@ -621,6 +621,10 @@
 /* PostgreSQL version as a number */
 #undef PG_VERSION_NUM
 
+#undef PG_CC_STR
+
+#undef PG_ARCH_STR
+
 /* A string containing the version number, platform, and C compiler */
 #undef PG_VERSION_STR
 
diff --git a/src/include/utils/system_version.h 
b/src/include/utils/system_version.h
index 18cb673d4ca..f9680527d55 100644
--- a/src/include/utils/system_version.h
+++ b/src/include/utils/system_version.h
@@ -11,6 +11,10 @@
 #ifndef SYSTEM_VERSION_H
 #define SYSTEM_VERSION_H
 
+#ifdef __GLIBC__
+#include <gnu/libc-version.h>
+#endif
+
 #define MAX_SYSTEM_VERSIONS 100
 
 typedef enum VersionType
@@ -34,5 +38,13 @@ typedef struct SystemVersion
 } SystemVersion;
 
 void           add_system_version(const char *name, SystemVersionCB cb, 
VersionType type);
+extern void register_core_versions(void);
+
+const char *core_get_version(bool *available);
+const char *core_get_arch(bool *available);
+const char *core_get_compiler(bool *available);
+
+const char *icu_get_version(bool *available);
+const char *glibc_get_version(bool *available);
 
 #endif                                                 /* SYSTEM_VERSION_H */
diff --git a/src/test/regress/expected/sysviews.out 
b/src/test/regress/expected/sysviews.out
index 3b37fafa65b..c813ef10eb5 100644
--- a/src/test/regress/expected/sysviews.out
+++ b/src/test/regress/expected/sysviews.out
@@ -233,3 +233,12 @@ select * from pg_timezone_abbrevs where abbrev = 'LMT';
  LMT    | @ 7 hours 52 mins 58 secs ago | f
 (1 row)
 
+-- 5 core versions should be present: architecture, ICU, core, compiler and
+-- glibc. If built with JIT support, one more record will be displayed
+-- containing LLVM version.
+select count(*) >= 5 as ok FROM pg_system_versions;
+ ok 
+----
+ t
+(1 row)
+
diff --git a/src/test/regress/sql/sysviews.sql 
b/src/test/regress/sql/sysviews.sql
index 66179f026b3..798a6dddd57 100644
--- a/src/test/regress/sql/sysviews.sql
+++ b/src/test/regress/sql/sysviews.sql
@@ -101,3 +101,8 @@ select count(distinct utc_offset) >= 24 as ok from 
pg_timezone_abbrevs;
 -- One specific case we can check without much fear of breakage
 -- is the historical local-mean-time value used for America/Los_Angeles.
 select * from pg_timezone_abbrevs where abbrev = 'LMT';
+
+-- 5 core versions should be present: architecture, ICU, core, compiler and
+-- glibc. If built with JIT support, one more record will be displayed
+-- containing LLVM version.
+select count(*) >= 5 as ok FROM pg_system_versions;
-- 
2.49.0

>From 7b71bc3ba1dada57dab8cab31a2911256ccf49a0 Mon Sep 17 00:00:00 2001
From: Dmitrii Dolgov <[email protected]>
Date: Sat, 5 Oct 2024 18:31:36 +0200
Subject: [PATCH v4 3/3] Add JIT provider version to pg_system_versions

Populate pg_system_versions with the JIT provider version. To actually
fetch the version, extend the JIT provider callbacks with the
get_version method. For LLVM provider llvm_version will be used, which
utilizes C-API LLVMGetVersion, available since LLVM 16.

The JIT provider will be initialized, when a first expression will be
compiled. For reporting purposes it's too late, thus register the
version at the backend startup, right after the core versions.
---
 src/backend/jit/jit.c          | 19 +++++++++++++++++++
 src/backend/jit/llvm/llvmjit.c | 19 +++++++++++++++++++
 src/backend/tcop/postgres.c    |  7 +++++++
 src/include/jit/jit.h          | 11 +++++++++++
 src/include/jit/llvmjit.h      |  2 ++
 5 files changed, 58 insertions(+)

diff --git a/src/backend/jit/jit.c b/src/backend/jit/jit.c
index d2ccef9de85..cd6505f0db0 100644
--- a/src/backend/jit/jit.c
+++ b/src/backend/jit/jit.c
@@ -188,3 +188,22 @@ InstrJitAgg(JitInstrumentation *dst, JitInstrumentation 
*add)
        INSTR_TIME_ADD(dst->optimization_counter, add->optimization_counter);
        INSTR_TIME_ADD(dst->emission_counter, add->emission_counter);
 }
+
+/*
+ * Return JIT provider's version string for troubleshooting purposes.
+ */
+const char *
+jit_get_version(bool *available)
+{
+       if (provider_init())
+               return provider.get_version(available);
+
+       *available = false;
+       return "";
+}
+
+void
+jit_register_version(void)
+{
+       add_system_version("LLVM", jit_get_version, RunTime);
+}
diff --git a/src/backend/jit/llvm/llvmjit.c b/src/backend/jit/llvm/llvmjit.c
index e978b996bae..9b40af60464 100644
--- a/src/backend/jit/llvm/llvmjit.c
+++ b/src/backend/jit/llvm/llvmjit.c
@@ -154,6 +154,7 @@ _PG_jit_provider_init(JitProviderCallbacks *cb)
        cb->reset_after_error = llvm_reset_after_error;
        cb->release_context = llvm_release_context;
        cb->compile_expr = llvm_compile_expr;
+       cb->get_version = llvm_version;
 }
 
 
@@ -1280,3 +1281,21 @@ ResOwnerReleaseJitContext(Datum res)
        context->resowner = NULL;
        jit_release_context(&context->base);
 }
+
+const char *
+llvm_version(bool *available)
+{
+#if LLVM_VERSION_MAJOR > 15
+       unsigned int major,
+                               minor,
+                               patch;
+
+       LLVMGetVersion(&major, &minor, &patch);
+
+       *available = true;
+       return (const char *) psprintf("%d.%d.%d", major, minor, patch);
+#else
+       *available = false;
+       return "";
+#endif
+}
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 3a8ff419425..a23a858f2c9 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -5248,4 +5248,11 @@ register_system_versions()
 {
        /* Set up reporting of core versions. */
        register_core_versions();
+
+       /*
+        * Set up reporting for JIT provider version. JIT provider 
initialization
+        * happens when the first expression is getting compiled, which is too
+        * late. Thus register the callback here instead.
+        */
+       jit_register_version();
 }
diff --git a/src/include/jit/jit.h b/src/include/jit/jit.h
index 33cb36c5d2e..8088ab37256 100644
--- a/src/include/jit/jit.h
+++ b/src/include/jit/jit.h
@@ -13,6 +13,7 @@
 
 #include "executor/instrument.h"
 #include "utils/resowner.h"
+#include "utils/system_version.h"
 
 
 /* Flags determining what kind of JIT operations to perform */
@@ -70,12 +71,14 @@ typedef void (*JitProviderResetAfterErrorCB) (void);
 typedef void (*JitProviderReleaseContextCB) (JitContext *context);
 struct ExprState;
 typedef bool (*JitProviderCompileExprCB) (struct ExprState *state);
+typedef const char *(*JitProviderVersion) (bool *available);
 
 struct JitProviderCallbacks
 {
        JitProviderResetAfterErrorCB reset_after_error;
        JitProviderReleaseContextCB release_context;
        JitProviderCompileExprCB compile_expr;
+       JitProviderVersion get_version;
 };
 
 
@@ -102,5 +105,13 @@ extern void jit_release_context(JitContext *context);
 extern bool jit_compile_expr(struct ExprState *state);
 extern void InstrJitAgg(JitInstrumentation *dst, JitInstrumentation *add);
 
+/*
+ * Get the provider's version string. The flag indicating availability is
+ * passed as an argument, and will be set accordingly if it's not possible to
+ * get the version.
+ */
+extern const char *jit_get_version(bool *available);
+
+extern void jit_register_version(void);
 
 #endif                                                 /* JIT_H */
diff --git a/src/include/jit/llvmjit.h b/src/include/jit/llvmjit.h
index b3c75022f55..1125451fbf5 100644
--- a/src/include/jit/llvmjit.h
+++ b/src/include/jit/llvmjit.h
@@ -145,6 +145,8 @@ extern LLVMTypeRef LLVMGetFunctionType(LLVMValueRef r);
 extern LLVMOrcObjectLayerRef 
LLVMOrcCreateRTDyldObjectLinkingLayerWithSafeSectionMemoryManager(LLVMOrcExecutionSessionRef
 ES);
 #endif
 
+extern const char* llvm_version(bool *available);
+
 #ifdef __cplusplus
 } /* extern "C" */
 #endif
-- 
2.49.0

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