diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8a802fb225..0d604e1a83 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23881,6 +23881,10 @@ SELECT currval(pg_get_serial_sequence('sometable', 'id'));
NO_SHOW_ALL: parameters excluded from
SHOW ALL commands.
+
+ NO_RESET: parameters do not support
+ RESET commands.
+
NO_RESET_ALL: parameters excluded from
RESET ALL commands.
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index f70f7f5c01..5732526415 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -1710,7 +1710,7 @@ static struct config_bool ConfigureNamesBool[] =
{"transaction_read_only", PGC_USERSET, CLIENT_CONN_STATEMENT,
gettext_noop("Sets the current transaction's read-only status."),
NULL,
- GUC_NO_RESET_ALL | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
+ GUC_NO_RESET | GUC_NO_RESET_ALL | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
},
&XactReadOnly,
false,
@@ -1729,7 +1729,7 @@ static struct config_bool ConfigureNamesBool[] =
{"transaction_deferrable", PGC_USERSET, CLIENT_CONN_STATEMENT,
gettext_noop("Whether to defer a read-only serializable transaction until it can be executed with no possible serialization failures."),
NULL,
- GUC_NO_RESET_ALL | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
+ GUC_NO_RESET | GUC_NO_RESET_ALL | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
},
&XactDeferrable,
false,
@@ -4753,7 +4753,7 @@ static struct config_enum ConfigureNamesEnum[] =
{"transaction_isolation", PGC_USERSET, CLIENT_CONN_STATEMENT,
gettext_noop("Sets the current transaction's isolation level."),
NULL,
- GUC_NO_RESET_ALL | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
+ GUC_NO_RESET | GUC_NO_RESET_ALL | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
},
&XactIsoLevel,
XACT_READ_COMMITTED, isolation_level_options,
@@ -7600,6 +7600,17 @@ set_config_option(const char *name, const char *value,
}
}
+ /* Disallow resetting and saving (and restoring) GUC_NO_RESET values */
+ if ((record->flags & GUC_NO_RESET) &&
+ (value == NULL || action == GUC_ACTION_SAVE))
+ {
+ ereport(elevel,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("parameter \"%s\" cannot be reset",
+ name)));
+ return 0;
+ }
+
/*
* Should we set reset/stacked values? (If so, the behavior is not
* transactional.) This is done either when we get a default value from
@@ -9723,7 +9734,7 @@ GetConfigOptionByName(const char *name, const char **varname, bool missing_ok)
Datum
pg_settings_get_flags(PG_FUNCTION_ARGS)
{
-#define MAX_GUC_FLAGS 5
+#define MAX_GUC_FLAGS 6
char *varname = TextDatumGetCString(PG_GETARG_DATUM(0));
struct config_generic *record;
int cnt = 0;
@@ -9738,6 +9749,8 @@ pg_settings_get_flags(PG_FUNCTION_ARGS)
if (record->flags & GUC_EXPLAIN)
flags[cnt++] = CStringGetTextDatum("EXPLAIN");
+ if (record->flags & GUC_NO_RESET)
+ flags[cnt++] = CStringGetTextDatum("NO_RESET");
if (record->flags & GUC_NO_RESET_ALL)
flags[cnt++] = CStringGetTextDatum("NO_RESET_ALL");
if (record->flags & GUC_NO_SHOW_ALL)
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index ea774968f0..18d522fdca 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -235,6 +235,8 @@ typedef enum
*/
#define GUC_RUNTIME_COMPUTED 0x200000
+#define GUC_NO_RESET 0x400000 /* not support RESET and save */
+
#define GUC_UNIT (GUC_UNIT_MEMORY | GUC_UNIT_TIME)
diff --git a/src/pl/plpgsql/src/expected/plpgsql_transaction.out b/src/pl/plpgsql/src/expected/plpgsql_transaction.out
index 254e5b7a70..759daf69be 100644
--- a/src/pl/plpgsql/src/expected/plpgsql_transaction.out
+++ b/src/pl/plpgsql/src/expected/plpgsql_transaction.out
@@ -576,16 +576,10 @@ BEGIN
PERFORM 1;
RAISE INFO '%', current_setting('transaction_isolation');
COMMIT;
- SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;
- RESET TRANSACTION ISOLATION LEVEL;
- PERFORM 1;
- RAISE INFO '%', current_setting('transaction_isolation');
- COMMIT;
END;
$$;
INFO: read committed
INFO: repeatable read
-INFO: read committed
-- error cases
DO LANGUAGE plpgsql $$
BEGIN
diff --git a/src/pl/plpgsql/src/sql/plpgsql_transaction.sql b/src/pl/plpgsql/src/sql/plpgsql_transaction.sql
index 8d76d00daa..f8efdb01b6 100644
--- a/src/pl/plpgsql/src/sql/plpgsql_transaction.sql
+++ b/src/pl/plpgsql/src/sql/plpgsql_transaction.sql
@@ -481,11 +481,6 @@ BEGIN
PERFORM 1;
RAISE INFO '%', current_setting('transaction_isolation');
COMMIT;
- SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;
- RESET TRANSACTION ISOLATION LEVEL;
- PERFORM 1;
- RAISE INFO '%', current_setting('transaction_isolation');
- COMMIT;
END;
$$;
diff --git a/src/test/regress/expected/guc.out b/src/test/regress/expected/guc.out
index 3de6404ba5..801d84bd39 100644
--- a/src/test/regress/expected/guc.out
+++ b/src/test/regress/expected/guc.out
@@ -839,6 +839,7 @@ SELECT pg_settings_get_flags('does_not_exist');
CREATE TABLE tab_settings_flags AS SELECT name, category,
'EXPLAIN' = ANY(flags) AS explain,
+ 'NO_RESET' = ANY(flags) AS no_reset,
'NO_RESET_ALL' = ANY(flags) AS no_reset_all,
'NO_SHOW_ALL' = ANY(flags) AS no_show_all,
'NOT_IN_SAMPLE' = ANY(flags) AS not_in_sample,
diff --git a/src/test/regress/expected/transactions.out b/src/test/regress/expected/transactions.out
index 599d511a67..01af8a1e01 100644
--- a/src/test/regress/expected/transactions.out
+++ b/src/test/regress/expected/transactions.out
@@ -44,6 +44,40 @@ SELECT * FROM xacttest;
777 | 777.777
(5 rows)
+-- Test that transaction characteristics cannot reset.
+BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE;
+SELECT count(*) FROM xacttest;
+ count
+-------
+ 5
+(1 row)
+
+RESET transaction_isolation; -- error
+ERROR: parameter "transaction_isolation" cannot be reset
+END;
+BEGIN TRANSACTION READ ONLY;
+SELECT count(*) FROM xacttest;
+ count
+-------
+ 5
+(1 row)
+
+RESET transaction_read_only; -- error
+ERROR: parameter "transaction_read_only" cannot be reset
+END;
+BEGIN TRANSACTION DEFERRABLE;
+SELECT count(*) FROM xacttest;
+ count
+-------
+ 5
+(1 row)
+
+RESET transaction_deferrable; -- error
+ERROR: parameter "transaction_deferrable" cannot be reset
+END;
+CREATE FUNCTION errfunc() RETURNS int LANGUAGE SQL AS 'SELECT 1'
+SET transaction_read_only = on; -- error
+ERROR: parameter "transaction_read_only" cannot be reset
-- Read-only tests
CREATE TABLE writetest (a int);
CREATE TEMPORARY TABLE temptest (a int);
diff --git a/src/test/regress/sql/guc.sql b/src/test/regress/sql/guc.sql
index d5db101e48..c8b612b5d5 100644
--- a/src/test/regress/sql/guc.sql
+++ b/src/test/regress/sql/guc.sql
@@ -324,6 +324,7 @@ SELECT pg_settings_get_flags(NULL);
SELECT pg_settings_get_flags('does_not_exist');
CREATE TABLE tab_settings_flags AS SELECT name, category,
'EXPLAIN' = ANY(flags) AS explain,
+ 'NO_RESET' = ANY(flags) AS no_reset,
'NO_RESET_ALL' = ANY(flags) AS no_reset_all,
'NO_SHOW_ALL' = ANY(flags) AS no_show_all,
'NOT_IN_SAMPLE' = ANY(flags) AS not_in_sample,
diff --git a/src/test/regress/sql/transactions.sql b/src/test/regress/sql/transactions.sql
index 0a716b506b..144ef09356 100644
--- a/src/test/regress/sql/transactions.sql
+++ b/src/test/regress/sql/transactions.sql
@@ -35,6 +35,24 @@ SELECT oid FROM pg_class WHERE relname = 'disappear';
-- should have members again
SELECT * FROM xacttest;
+-- Test that transaction characteristics cannot reset.
+BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE;
+SELECT count(*) FROM xacttest;
+RESET transaction_isolation; -- error
+END;
+
+BEGIN TRANSACTION READ ONLY;
+SELECT count(*) FROM xacttest;
+RESET transaction_read_only; -- error
+END;
+
+BEGIN TRANSACTION DEFERRABLE;
+SELECT count(*) FROM xacttest;
+RESET transaction_deferrable; -- error
+END;
+
+CREATE FUNCTION errfunc() RETURNS int LANGUAGE SQL AS 'SELECT 1'
+SET transaction_read_only = on; -- error
-- Read-only tests