Subject: [PATCH 2/2] Expose GUC flags in SQL function; retire ./check_guc

From: Justin Pryzby <[email-masked]>
Date: Wed, 8 Dec 2021 12:06:35 -0600

---
 doc/src/sgml/func.sgml            |  15 ++++
 src/backend/utils/misc/check_guc  |  29 -------
 src/backend/utils/misc/guc.c      |  37 +++++++++
 src/include/catalog/pg_proc.dat   |   6 ++
 src/include/utils/guc.h           |   3 +-
 src/test/regress/expected/guc.out | 122 ++++++++++++++++++++++++++++++
 src/test/regress/sql/guc.sql      |  72 ++++++++++++++++++
 7 files changed, 254 insertions(+), 30 deletions(-)
 delete mode 100755 src/backend/utils/misc/check_guc

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 0ee6974f1c6..cbdbccb63d1 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23596,6 +23596,21 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
        </para></entry>
       </row>
 
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <indexterm>
+         <primary>pg_get_get_flags</primary>
+        </indexterm>
+        <function>pg_get_get_flags</function> ( <parameter>guc</parameter> <type>text</type> )
+        <returnvalue>text[]</returnvalue>
+       </para>
+       <para>
+        Return an array of flags associated with the given GUC, or NULL if the
+        GUC does not exist.  Not all flags are exposed; the set of flags which
+        are exposed is subject to change.
+       </para></entry>
+      </row>
+
       <row>
        <entry role="func_table_entry"><para role="func_signature">
         <indexterm>
diff --git a/src/backend/utils/misc/check_guc b/src/backend/utils/misc/check_guc
deleted file mode 100755
index 323ca13191b..00000000000
--- a/src/backend/utils/misc/check_guc
+++ /dev/null
@@ -1,29 +0,0 @@
-#! /bin/sh
-set -e
-
-## this script makes some assumptions about the formatting of files it parses.
-## in postgresql.conf.sample:
-##   1) the valid config settings may be preceded by a '#', but NOT '# '
-##      (we use this to skip comments)
-
-### What options are listed in postgresql.conf.sample, but don't appear
-### in guc.c?
-
-# grab everything that looks like a setting
-SETTINGS=`sed '/^#[[:alnum:]]/!d; s/^#//; s/ =.*//; /^include/d' postgresql.conf.sample`
-
-for i in $SETTINGS ; do
-  ## it sure would be nice to replace this with an sql "not in" statement
-  grep -i "\"$i\"" guc.c >/dev/null ||
-    echo "$i seems to be missing from guc.c";
-done
-
-### What options are listed in guc.c, but don't appear
-### in postgresql.conf.sample?
-
-# grab everything that looks like a setting and convert it to lower case
-SETTINGS=`gawk -F '[",]' 'BEGIN{RS="\n\t\\\\{\n"} /",[[:space:]]*PGC_.*.*gettext_noop/ && !/NOT_IN_SAMPLE/{print tolower($2)}' guc.c`
-for i in $SETTINGS ; do
-  grep "#$i " postgresql.conf.sample >/dev/null ||
-    echo "$i seems to be missing from postgresql.conf.sample";
-done
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 4c94f09c645..d3b56b2007c 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -9634,6 +9634,43 @@ GetConfigOptionByName(const char *name, const char **varname, bool missing_ok)
 	return _ShowOption(record, true);
 }
 
+/*
+ * Return some flags for the specified GUC, or NULL if it doesn't exist.
+ */
+Datum
+pg_get_guc_flags(PG_FUNCTION_ARGS)
+{
+	char *varname = TextDatumGetCString(PG_GETARG_DATUM(0));
+	struct config_generic *record;
+	int			cnt = 0;
+#define MAX_NUM_FLAGS	5
+	Datum      flags[MAX_NUM_FLAGS];
+	ArrayType	*a;
+
+	record = find_option(varname, false, true, ERROR);
+
+	/* return NULL if no such variable */
+	if (record == NULL)
+		PG_RETURN_NULL();
+
+	if (record->flags & GUC_NO_SHOW_ALL)
+		flags[cnt++] = CStringGetTextDatum("NO_SHOW_ALL");
+	if (record->flags & GUC_NO_RESET_ALL)
+		flags[cnt++] = CStringGetTextDatum("NO_RESET_ALL");
+	if (record->flags & GUC_NOT_IN_SAMPLE)
+		flags[cnt++] = CStringGetTextDatum("NOT_IN_SAMPLE");
+	if (record->flags & GUC_EXPLAIN)
+		flags[cnt++] = CStringGetTextDatum("EXPLAIN");
+	if (record->flags & GUC_RUNTIME_COMPUTED)
+		flags[cnt++] = CStringGetTextDatum("RUNTIME_COMPUTED");
+
+	Assert(cnt <= MAX_NUM_FLAGS);
+
+	/* Returns the record as Datum */
+	a = construct_array(flags, cnt, TEXTOID, -1, false, TYPALIGN_INT);
+	PG_RETURN_ARRAYTYPE_P(a);
+}
+
 /*
  * Return GUC variable value by variable number; optionally return canonical
  * form of name.  Return value is palloc'd.
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 0859dc81cac..562c1d779cb 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6096,6 +6096,12 @@
   proargmodes => '{o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}',
   proargnames => '{name,setting,unit,category,short_desc,extra_desc,context,vartype,source,min_val,max_val,enumvals,boot_val,reset_val,sourcefile,sourceline,pending_restart}',
   prosrc => 'show_all_settings' },
+
+{ oid => '8921', descr => 'return flags for specified GUC',
+  proname => 'pg_get_guc_flags', provolatile => 's',
+  prorettype => '_text', proargtypes => 'text',
+  prosrc => 'pg_get_guc_flags' },
+
 { oid => '3329', descr => 'show config file settings',
   proname => 'pg_show_all_file_settings', prorows => '1000', proretset => 't',
   provolatile => 'v', prorettype => 'record', proargtypes => '',
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index 6bb81707b09..1ac20f85ab3 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -198,8 +198,9 @@ typedef enum
 
 #define GUC_QUALIFIER_SEPARATOR '.'
 
-/*
+/* --
  * bit values in "flags" of a GUC variable
+ * Consider if any new flags should be exposed in pg_get_guc_flags().
  */
 #define GUC_LIST_INPUT			0x0001	/* input can be list format */
 #define GUC_LIST_QUOTE			0x0002	/* double-quote list elements */
diff --git a/src/test/regress/expected/guc.out b/src/test/regress/expected/guc.out
index 59da91ff04d..29173f3ce8e 100644
--- a/src/test/regress/expected/guc.out
+++ b/src/test/regress/expected/guc.out
@@ -813,3 +813,125 @@ set default_with_oids to f;
 -- Should not allow to set it to true.
 set default_with_oids to t;
 ERROR:  tables declared WITH OIDS are not supported
+--
+-- Test GUC categories and flags.
+--
+CREATE TABLE pg_settings_flags AS SELECT name, category,
+	'NO_SHOW_ALL'	=ANY(flags) AS no_show_all,
+	'NO_RESET_ALL'	=ANY(flags) AS no_reset_all,
+	'NOT_IN_SAMPLE'	=ANY(flags) AS not_in_sample,
+	'EXPLAIN'	=ANY(flags) AS guc_explain,
+	'COMPUTED'	=ANY(flags) AS guc_computed
+	FROM pg_show_all_settings() AS psas, pg_get_guc_flags(psas.name) AS flags;
+-- test that GUCS are in postgresql.conf
+SELECT lower(name) FROM pg_settings_flags WHERE NOT not_in_sample EXCEPT
+SELECT regexp_replace(ln, '^#?([_[:alpha:]]+) (= .*|[^ ]*$)', '\1') AS guc
+FROM (SELECT regexp_split_to_table(pg_read_file('postgresql.conf'), '\n') AS ln) conf
+WHERE ln ~ '^#?[[:alpha:]]'
+ORDER BY 1;
+            lower            
+-----------------------------
+ config_file
+ plpgsql.check_asserts
+ plpgsql.extra_errors
+ plpgsql.extra_warnings
+ plpgsql.print_strict_params
+ plpgsql.variable_conflict
+(6 rows)
+
+-- test that lines in postgresql.conf that look like GUCs are GUCs
+SELECT regexp_replace(ln, '^#?([_[:alpha:]]+) (= .*|[^ ]*$)', '\1') AS guc
+FROM (SELECT regexp_split_to_table(pg_read_file('postgresql.conf'), '\n') AS ln) conf
+WHERE ln ~ '^#?[[:alpha:]]'
+EXCEPT SELECT lower(name) FROM pg_settings_flags WHERE NOT not_in_sample
+ORDER BY 1;
+        guc        
+-------------------
+ include
+ include_dir
+ include_if_exists
+(3 rows)
+
+-- test that section:DEVELOPER GUCs are flagged GUC_NOT_IN_SAMPLE:
+SELECT * FROM pg_settings_flags
+WHERE category='Developer Options' AND NOT not_in_sample
+ORDER BY 1;
+ name | category | no_show_all | no_reset_all | not_in_sample | guc_explain | guc_computed 
+------+----------+-------------+--------------+---------------+-------------+--------------
+(0 rows)
+
+-- Maybe the converse:
+SELECT * FROM pg_settings_flags
+WHERE category NOT IN ('Developer Options', 'Preset Options') AND not_in_sample
+ORDER BY 1;
+          name          |                    category                     | no_show_all | no_reset_all | not_in_sample | guc_explain | guc_computed 
+------------------------+-------------------------------------------------+-------------+--------------+---------------+-------------+--------------
+ application_name       | Reporting and Logging / What to Log             | f           | f            | t             | f           | f
+ transaction_deferrable | Client Connection Defaults / Statement Behavior | f           | t            | t             | f           | f
+ transaction_isolation  | Client Connection Defaults / Statement Behavior | f           | t            | t             | f           | f
+ transaction_read_only  | Client Connection Defaults / Statement Behavior | f           | t            | t             | f           | f
+(4 rows)
+
+-- Most Query Tuning GUCs are flagged as EXPLAIN:
+SELECT * FROM pg_settings_flags
+WHERE category ~ '^Query Tuning' AND NOT guc_explain
+ORDER BY 1;
+           name            |               category               | no_show_all | no_reset_all | not_in_sample | guc_explain | guc_computed 
+---------------------------+--------------------------------------+-------------+--------------+---------------+-------------+--------------
+ default_statistics_target | Query Tuning / Other Planner Options | f           | f            | f             | f           | f
+(1 row)
+
+-- Maybe the converse:
+SELECT * FROM pg_settings_flags
+WHERE guc_explain AND NOT category ~ '^Query Tuning|^Resource Usage'
+ORDER BY 1;
+        name         |                    category                     | no_show_all | no_reset_all | not_in_sample | guc_explain | guc_computed 
+---------------------+-------------------------------------------------+-------------+--------------+---------------+-------------+--------------
+ force_parallel_mode | Developer Options                               | f           | f            | t             | t           | f
+ search_path         | Client Connection Defaults / Statement Behavior | f           | f            | f             | t           | f
+(2 rows)
+
+-- GUCs flagged RUNTIME are Preset
+SELECT * FROM pg_settings_flags
+WHERE guc_computed AND NOT category='Preset Options'
+ORDER BY 1;
+ name | category | no_show_all | no_reset_all | not_in_sample | guc_explain | guc_computed 
+------+----------+-------------+--------------+---------------+-------------+--------------
+(0 rows)
+
+-- PRESET GUCs are flagged NOT_IN_SAMPLE
+SELECT * FROM pg_settings_flags
+WHERE category='Preset Options' AND NOT not_in_sample
+ORDER BY 1;
+ name | category | no_show_all | no_reset_all | not_in_sample | guc_explain | guc_computed 
+------+----------+-------------+--------------+---------------+-------------+--------------
+(0 rows)
+
+-- NO_SHOW_ALL implies NO_RESET_ALL:
+SELECT * FROM pg_settings_flags
+WHERE no_show_all AND NOT no_reset_all
+ORDER BY 1;
+ name | category | no_show_all | no_reset_all | not_in_sample | guc_explain | guc_computed 
+------+----------+-------------+--------------+---------------+-------------+--------------
+(0 rows)
+
+-- Usually the converse:
+SELECT * FROM pg_settings_flags
+WHERE NOT no_show_all AND no_reset_all
+ORDER BY 1;
+          name          |                    category                     | no_show_all | no_reset_all | not_in_sample | guc_explain | guc_computed 
+------------------------+-------------------------------------------------+-------------+--------------+---------------+-------------+--------------
+ transaction_deferrable | Client Connection Defaults / Statement Behavior | f           | t            | t             | f           | f
+ transaction_isolation  | Client Connection Defaults / Statement Behavior | f           | t            | t             | f           | f
+ transaction_read_only  | Client Connection Defaults / Statement Behavior | f           | t            | t             | f           | f
+(3 rows)
+
+-- NO_SHOW_ALL implies NOT_IN_SAMPLE:
+SELECT * FROM pg_settings_flags
+WHERE no_show_all AND NOT not_in_sample
+ORDER BY 1;
+ name | category | no_show_all | no_reset_all | not_in_sample | guc_explain | guc_computed 
+------+----------+-------------+--------------+---------------+-------------+--------------
+(0 rows)
+
+DROP TABLE pg_settings_flags;
diff --git a/src/test/regress/sql/guc.sql b/src/test/regress/sql/guc.sql
index c39c11388d5..47b6a233d5c 100644
--- a/src/test/regress/sql/guc.sql
+++ b/src/test/regress/sql/guc.sql
@@ -311,3 +311,75 @@ reset check_function_bodies;
 set default_with_oids to f;
 -- Should not allow to set it to true.
 set default_with_oids to t;
+
+--
+-- Test GUC categories and flags.
+--
+CREATE TABLE pg_settings_flags AS SELECT name, category,
+	'NO_SHOW_ALL'	=ANY(flags) AS no_show_all,
+	'NO_RESET_ALL'	=ANY(flags) AS no_reset_all,
+	'NOT_IN_SAMPLE'	=ANY(flags) AS not_in_sample,
+	'EXPLAIN'	=ANY(flags) AS guc_explain,
+	'COMPUTED'	=ANY(flags) AS guc_computed
+	FROM pg_show_all_settings() AS psas, pg_get_guc_flags(psas.name) AS flags;
+
+-- test that GUCS are in postgresql.conf
+SELECT lower(name) FROM pg_settings_flags WHERE NOT not_in_sample EXCEPT
+SELECT regexp_replace(ln, '^#?([_[:alpha:]]+) (= .*|[^ ]*$)', '\1') AS guc
+FROM (SELECT regexp_split_to_table(pg_read_file('postgresql.conf'), '\n') AS ln) conf
+WHERE ln ~ '^#?[[:alpha:]]'
+ORDER BY 1;
+
+-- test that lines in postgresql.conf that look like GUCs are GUCs
+SELECT regexp_replace(ln, '^#?([_[:alpha:]]+) (= .*|[^ ]*$)', '\1') AS guc
+FROM (SELECT regexp_split_to_table(pg_read_file('postgresql.conf'), '\n') AS ln) conf
+WHERE ln ~ '^#?[[:alpha:]]'
+EXCEPT SELECT lower(name) FROM pg_settings_flags WHERE NOT not_in_sample
+ORDER BY 1;
+
+-- test that section:DEVELOPER GUCs are flagged GUC_NOT_IN_SAMPLE:
+SELECT * FROM pg_settings_flags
+WHERE category='Developer Options' AND NOT not_in_sample
+ORDER BY 1;
+
+-- Maybe the converse:
+SELECT * FROM pg_settings_flags
+WHERE category NOT IN ('Developer Options', 'Preset Options') AND not_in_sample
+ORDER BY 1;
+
+-- Most Query Tuning GUCs are flagged as EXPLAIN:
+SELECT * FROM pg_settings_flags
+WHERE category ~ '^Query Tuning' AND NOT guc_explain
+ORDER BY 1;
+
+-- Maybe the converse:
+SELECT * FROM pg_settings_flags
+WHERE guc_explain AND NOT category ~ '^Query Tuning|^Resource Usage'
+ORDER BY 1;
+
+-- GUCs flagged RUNTIME are Preset
+SELECT * FROM pg_settings_flags
+WHERE guc_computed AND NOT category='Preset Options'
+ORDER BY 1;
+
+-- PRESET GUCs are flagged NOT_IN_SAMPLE
+SELECT * FROM pg_settings_flags
+WHERE category='Preset Options' AND NOT not_in_sample
+ORDER BY 1;
+
+-- NO_SHOW_ALL implies NO_RESET_ALL:
+SELECT * FROM pg_settings_flags
+WHERE no_show_all AND NOT no_reset_all
+ORDER BY 1;
+
+-- Usually the converse:
+SELECT * FROM pg_settings_flags
+WHERE NOT no_show_all AND no_reset_all
+ORDER BY 1;
+
+-- NO_SHOW_ALL implies NOT_IN_SAMPLE:
+SELECT * FROM pg_settings_flags
+WHERE no_show_all AND NOT not_in_sample
+ORDER BY 1;
+
+DROP TABLE pg_settings_flags;
-- 
2.17.1

--i3WE5m5QLioBhvvb--