Hi
Itested my older patch for session variables with dedicated system catalog,
and I was surprised so one independent test fails
src/test/modules/injection_points/expected/syscache-update-pruned.out
you can apply attached patch, and run test
# using temp instance on port 58928 with PID 422150
ok 1 - basic 82 ms
ok 2 - inplace 1556 ms
not ok 3 - syscache-update-pruned 719 ms
ok 4 - heap_lock_update 157 ms
1..4
# 1 of 4 tests failed.
pavel@nemesis:~/src/postgresql$ cat
/home/pavel/src/postgresql/src/test/modules/injection_points/output_iso/regression.diffs
diff -U3
/home/pavel/src/postgresql/src/test/modules/injection_points/expected/syscache-update-pruned.out
/home/pavel/src/postgresql/src/test/modules/injection_points/output_iso/results/syscache-update-pruned.out
---
/home/pavel/src/postgresql/src/test/modules/injection_points/expected/syscache-update-pruned.out
2026-02-19 05:31:42.352060555 +0100
+++
/home/pavel/src/postgresql/src/test/modules/injection_points/output_iso/results/syscache-update-pruned.out
2026-03-09 06:50:54.521741837 +0100
@@ -75,6 +75,7 @@
SELECT FROM injection_points_wakeup('heap_update-before-pin');
<waiting ...>
step grant1: <... completed>
+ERROR: tuple concurrently deleted
step wakegrant4: <... completed>
step inspect4:
SELECT relhastriggers, relhassubclass FROM pg_class
@@ -82,6 +83,6 @@
relhastriggers|relhassubclass
--------------+--------------
-f |f
+t |t
(1 row)
Regards
Pavel
From 433bee053226f2c9ce5418772e2abda9b491b25f Mon Sep 17 00:00:00 2001
From: "[email protected]" <[email protected]>
Date: Wed, 28 May 2025 08:30:25 +0200
Subject: [PATCH] introduce new class (catalog) pg_variable
This table holds metadata about session variables created by
command CREATE VARIABLE, and dropped by command DROP VARIABLE.
---
doc/src/sgml/catalogs.sgml | 133 ++++++++++++++++++++
src/backend/catalog/Makefile | 1 +
src/backend/catalog/meson.build | 1 +
src/backend/catalog/pg_variable.c | 168 +++++++++++++++++++++++++
src/include/catalog/Makefile | 3 +-
src/include/catalog/meson.build | 1 +
src/include/catalog/pg_variable.h | 96 ++++++++++++++
src/test/regress/expected/oidjoins.out | 4 +
src/tools/pgindent/typedefs.list | 2 +
9 files changed, 408 insertions(+), 1 deletion(-)
create mode 100644 src/backend/catalog/pg_variable.c
create mode 100644 src/include/catalog/pg_variable.h
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 69588937719..f61c3ec8069 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -369,6 +369,11 @@
<entry><link linkend="catalog-pg-user-mapping"><structname>pg_user_mapping</structname></link></entry>
<entry>mappings of users to foreign servers</entry>
</row>
+
+ <row>
+ <entry><link linkend="catalog-pg-variable"><structname>pg_variable</structname></link></entry>
+ <entry>session variables</entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -9908,4 +9913,132 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l
</table>
</sect1>
+ <sect1 id="catalog-pg-variable">
+ <title><structname>pg_variable</structname></title>
+
+ <indexterm zone="catalog-pg-variable">
+ <primary>pg_variable</primary>
+ </indexterm>
+
+ <para>
+ The catalog <structname>pg_variable</structname> stores information about
+ session variables.
+ </para>
+
+ <table>
+ <title><structname>pg_variable</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>oid</structfield> <type>oid</type>
+ </para>
+ <para>
+ Row identifier
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>vartype</structfield> <type>oid</type>
+ (references <link linkend="catalog-pg-type"><structname>pg_type</structname></link>.<structfield>oid</structfield>)
+ </para>
+ <para>
+ The OID of the variable's data type
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>varcreate_lsn</structfield> <type>pg_lsn</type>
+ </para>
+ <para>
+ LSN of the transaction where the variable was created.
+ <structfield>varcreate_lsn</structfield> and
+ <structfield>oid</structfield> together form the all-time unique
+ identifier (<structfield>oid</structfield> alone is not enough, since
+ object identifiers can get reused).
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>varname</structfield> <type>name</type>
+ </para>
+ <para>
+ Name of the session variable
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>varnamespace</structfield> <type>oid</type>
+ (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>oid</structfield>)
+ </para>
+ <para>
+ The OID of the namespace that contains this variable
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>varowner</structfield> <type>oid</type>
+ (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>oid</structfield>)
+ </para>
+ <para>
+ Owner of the variable
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>vartypmod</structfield> <type>int4</type>
+ </para>
+ <para>
+ <structfield>vartypmod</structfield> records type-specific data
+ supplied at variable creation time (for example, the maximum
+ length of a <type>varchar</type> column). It is passed to
+ type-specific input functions and length coercion functions.
+ The value will generally be -1 for types that do not need <structfield>vartypmod</structfield>.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>varcollation</structfield> <type>oid</type>
+ (references <link linkend="catalog-pg-collation"><structname>pg_collation</structname></link>.<structfield>oid</structfield>)
+ </para>
+ <para>
+ The defined collation of the variable, or zero if the variable is
+ not of a collatable data type.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>varacl</structfield> <type>aclitem[]</type>
+ </para>
+ <para>
+ Access privileges; see
+ <xref linkend="sql-grant"/> and
+ <xref linkend="sql-revoke"/>
+ for details
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+ </sect1>
</chapter>
diff --git a/src/backend/catalog/Makefile b/src/backend/catalog/Makefile
index 26fa0c9b18c..c425ab4cbcb 100644
--- a/src/backend/catalog/Makefile
+++ b/src/backend/catalog/Makefile
@@ -46,6 +46,7 @@ OBJS = \
pg_subscription.o \
pg_tablespace.o \
pg_type.o \
+ pg_variable.o \
storage.o \
toasting.o
diff --git a/src/backend/catalog/meson.build b/src/backend/catalog/meson.build
index 11d21c5ad6b..964adf918ab 100644
--- a/src/backend/catalog/meson.build
+++ b/src/backend/catalog/meson.build
@@ -33,6 +33,7 @@ backend_sources += files(
'pg_subscription.c',
'pg_tablespace.c',
'pg_type.c',
+ 'pg_variable.c',
'storage.c',
'toasting.c',
)
diff --git a/src/backend/catalog/pg_variable.c b/src/backend/catalog/pg_variable.c
new file mode 100644
index 00000000000..bd6a29a79e5
--- /dev/null
+++ b/src/backend/catalog/pg_variable.c
@@ -0,0 +1,168 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_variable.c
+ * session variables
+ *
+ * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ * src/backend/catalog/pg_variable.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/heapam.h"
+#include "catalog/dependency.h"
+#include "catalog/indexing.h"
+#include "catalog/namespace.h"
+#include "catalog/objectaccess.h"
+#include "catalog/pg_collation.h"
+#include "catalog/pg_namespace.h"
+#include "catalog/pg_variable.h"
+#include "utils/builtins.h"
+#include "utils/pg_lsn.h"
+#include "utils/syscache.h"
+
+/*
+ * Creates entry in pg_variable table
+ */
+ObjectAddress
+create_variable(const char *varName,
+ Oid varNamespace,
+ Oid varType,
+ int32 varTypmod,
+ Oid varOwner,
+ Oid varCollation,
+ bool if_not_exists)
+{
+ NameData varname;
+ bool nulls[Natts_pg_variable];
+ Datum values[Natts_pg_variable];
+ Relation rel;
+ HeapTuple tup;
+ TupleDesc tupdesc;
+ ObjectAddress myself,
+ referenced;
+ ObjectAddresses *addrs;
+ Oid varid;
+
+ Assert(varName);
+ Assert(OidIsValid(varNamespace));
+ Assert(OidIsValid(varType));
+ Assert(OidIsValid(varOwner));
+
+ rel = table_open(VariableRelationId, RowExclusiveLock);
+
+ /*
+ * Check for duplicates. Note that this does not really prevent
+ * duplicates, it's here just to provide nicer error message in common
+ * case. The real protection is the unique key on the catalog.
+ */
+ if (SearchSysCacheExists2(VARIABLENAMENSP,
+ PointerGetDatum(varName),
+ ObjectIdGetDatum(varNamespace)))
+ {
+ if (if_not_exists)
+ ereport(NOTICE,
+ (errcode(ERRCODE_DUPLICATE_OBJECT),
+ errmsg("session variable \"%s\" already exists, skipping",
+ varName)));
+ else
+ ereport(ERROR,
+ (errcode(ERRCODE_DUPLICATE_OBJECT),
+ errmsg("session variable \"%s\" already exists",
+ varName)));
+
+ table_close(rel, RowExclusiveLock);
+
+ return InvalidObjectAddress;
+ }
+
+ memset(values, 0, sizeof(values));
+ memset(nulls, false, sizeof(nulls));
+
+ namestrcpy(&varname, varName);
+
+ varid = GetNewOidWithIndex(rel, VariableOidIndexId, Anum_pg_variable_oid);
+
+ values[Anum_pg_variable_oid - 1] = ObjectIdGetDatum(varid);
+ values[Anum_pg_variable_varcreate_lsn - 1] = LSNGetDatum(GetXLogInsertRecPtr());
+ values[Anum_pg_variable_varname - 1] = NameGetDatum(&varname);
+ values[Anum_pg_variable_varnamespace - 1] = ObjectIdGetDatum(varNamespace);
+ values[Anum_pg_variable_vartype - 1] = ObjectIdGetDatum(varType);
+ values[Anum_pg_variable_vartypmod - 1] = Int32GetDatum(varTypmod);
+ values[Anum_pg_variable_varowner - 1] = ObjectIdGetDatum(varOwner);
+ values[Anum_pg_variable_varcollation - 1] = ObjectIdGetDatum(varCollation);
+
+ nulls[Anum_pg_variable_varacl - 1] = true;
+
+ tupdesc = RelationGetDescr(rel);
+
+ tup = heap_form_tuple(tupdesc, values, nulls);
+ CatalogTupleInsert(rel, tup);
+ Assert(OidIsValid(varid));
+
+ addrs = new_object_addresses();
+
+ ObjectAddressSet(myself, VariableRelationId, varid);
+
+ /* dependency on namespace */
+ ObjectAddressSet(referenced, NamespaceRelationId, varNamespace);
+ add_exact_object_address(&referenced, addrs);
+
+ /* dependency on used type */
+ ObjectAddressSet(referenced, TypeRelationId, varType);
+ add_exact_object_address(&referenced, addrs);
+
+ /* dependency on collation */
+ if (OidIsValid(varCollation) &&
+ varCollation != DEFAULT_COLLATION_OID)
+ {
+ ObjectAddressSet(referenced, CollationRelationId, varCollation);
+ add_exact_object_address(&referenced, addrs);
+ }
+
+ record_object_address_dependencies(&myself, addrs, DEPENDENCY_NORMAL);
+ free_object_addresses(addrs);
+
+ /* dependency on owner */
+ recordDependencyOnOwner(VariableRelationId, varid, varOwner);
+
+ /* dependency on extension */
+ recordDependencyOnCurrentExtension(&myself, false);
+
+ heap_freetuple(tup);
+
+ /* post creation hook for new function */
+ InvokeObjectPostCreateHook(VariableRelationId, varid, 0);
+
+ table_close(rel, RowExclusiveLock);
+
+ return myself;
+}
+
+/*
+ * Drop variable by OID
+ */
+void
+DropVariableById(Oid varid)
+{
+ Relation rel;
+ HeapTuple tup;
+
+ rel = table_open(VariableRelationId, RowExclusiveLock);
+
+ tup = SearchSysCache1(VARIABLEOID, ObjectIdGetDatum(varid));
+
+ if (!HeapTupleIsValid(tup))
+ elog(ERROR, "cache lookup failed for variable %u", varid);
+
+ CatalogTupleDelete(rel, &tup->t_self);
+
+ ReleaseSysCache(tup);
+
+ table_close(rel, RowExclusiveLock);
+}
diff --git a/src/include/catalog/Makefile b/src/include/catalog/Makefile
index 444fc76eed6..91e18c1ecc4 100644
--- a/src/include/catalog/Makefile
+++ b/src/include/catalog/Makefile
@@ -81,7 +81,8 @@ CATALOG_HEADERS := \
pg_publication_namespace.h \
pg_publication_rel.h \
pg_subscription.h \
- pg_subscription_rel.h
+ pg_subscription_rel.h \
+ pg_variable.h
GENERATED_HEADERS := $(CATALOG_HEADERS:%.h=%_d.h)
diff --git a/src/include/catalog/meson.build b/src/include/catalog/meson.build
index bcc01c87c2e..470a25faa33 100644
--- a/src/include/catalog/meson.build
+++ b/src/include/catalog/meson.build
@@ -69,6 +69,7 @@ catalog_headers = [
'pg_publication_rel.h',
'pg_subscription.h',
'pg_subscription_rel.h',
+ 'pg_variable.h',
]
# The .dat files we need can just be listed alphabetically.
diff --git a/src/include/catalog/pg_variable.h b/src/include/catalog/pg_variable.h
new file mode 100644
index 00000000000..15f530894c5
--- /dev/null
+++ b/src/include/catalog/pg_variable.h
@@ -0,0 +1,96 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_variable.h
+ * definition of session variables system catalog (pg_variables)
+ *
+ *
+ * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/catalog/pg_variable.h
+ *
+ * NOTES
+ * The Catalog.pm module reads this file and derives schema
+ * information.
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef PG_VARIABLE_H
+#define PG_VARIABLE_H
+
+#include "access/xlogdefs.h"
+#include "catalog/genbki.h"
+#include "catalog/objectaddress.h"
+#include "catalog/pg_variable_d.h"
+#include "utils/acl.h"
+
+/* ----------------
+ * pg_variable definition. cpp turns this into
+ * typedef struct FormData_pg_variable
+ * ----------------
+ */
+CATALOG(pg_variable,9222,VariableRelationId)
+{
+ Oid oid; /* oid */
+
+ /* OID of entry in pg_type for variable's type */
+ Oid vartype BKI_LOOKUP(pg_type);
+
+ /*
+ * Used for identity check [oid, create_lsn].
+ *
+ * This column of the 8-byte XlogRecPtr type should be at an address that
+ * is divisible by 8, but before any column of type NameData.
+ */
+ XLogRecPtr varcreate_lsn;
+
+ /* variable name */
+ NameData varname;
+
+ /* OID of namespace containing variable class */
+ Oid varnamespace BKI_LOOKUP(pg_namespace);
+
+ /* variable owner */
+ Oid varowner BKI_LOOKUP(pg_authid);
+
+ /* typmod for variable's type */
+ int32 vartypmod BKI_DEFAULT(-1);
+
+ /* variable collation */
+ Oid varcollation BKI_DEFAULT(0) BKI_LOOKUP_OPT(pg_collation);
+
+
+#ifdef CATALOG_VARLEN /* variable-length fields start here */
+
+ /* access permissions */
+ aclitem varacl[1] BKI_DEFAULT(_null_);
+
+#endif
+} FormData_pg_variable;
+
+/* ----------------
+ * Form_pg_variable corresponds to a pointer to a tuple with
+ * the format of the pg_variable relation.
+ * ----------------
+ */
+typedef FormData_pg_variable *Form_pg_variable;
+
+DECLARE_TOAST(pg_variable, 9223, 9224);
+
+DECLARE_UNIQUE_INDEX_PKEY(pg_variable_oid_index, 9225, VariableOidIndexId, pg_variable, btree(oid oid_ops));
+DECLARE_UNIQUE_INDEX(pg_variable_varname_nsp_index, 9226, VariableNameNspIndexId, pg_variable, btree(varname name_ops, varnamespace oid_ops));
+
+MAKE_SYSCACHE(VARIABLENAMENSP, pg_variable_varname_nsp_index, 8);
+MAKE_SYSCACHE(VARIABLEOID, pg_variable_oid_index, 8);
+
+extern ObjectAddress create_variable(const char *varName,
+ Oid varNamespace,
+ Oid varType,
+ int32 varTypmod,
+ Oid varOwner,
+ Oid varCollation,
+ bool if_not_exists);
+
+extern void DropVariableById(Oid varid);
+
+#endif /* PG_VARIABLE_H */
diff --git a/src/test/regress/expected/oidjoins.out b/src/test/regress/expected/oidjoins.out
index 51b9608a668..168dc662989 100644
--- a/src/test/regress/expected/oidjoins.out
+++ b/src/test/regress/expected/oidjoins.out
@@ -273,3 +273,7 @@ NOTICE: checking pg_subscription {subowner} => pg_authid {oid}
NOTICE: checking pg_subscription {subserver} => pg_foreign_server {oid}
NOTICE: checking pg_subscription_rel {srsubid} => pg_subscription {oid}
NOTICE: checking pg_subscription_rel {srrelid} => pg_class {oid}
+NOTICE: checking pg_variable {vartype} => pg_type {oid}
+NOTICE: checking pg_variable {varnamespace} => pg_namespace {oid}
+NOTICE: checking pg_variable {varowner} => pg_authid {oid}
+NOTICE: checking pg_variable {varcollation} => pg_collation {oid}
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 3250564d4ff..fdb7629bca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -928,6 +928,7 @@ FormData_pg_ts_parser
FormData_pg_ts_template
FormData_pg_type
FormData_pg_user_mapping
+FormData_pg_variable
FormExtraData_pg_attribute
Form_pg_aggregate
Form_pg_am
@@ -987,6 +988,7 @@ Form_pg_ts_parser
Form_pg_ts_template
Form_pg_type
Form_pg_user_mapping
+Form_pg_variable
FormatNode
FreeBlockNumberArray
FreeListData
--
2.53.0
