Implement enum type for guc parameters, and convert a couple of existing

variables to it. More need to be converted, but I wanted to get this in
before it conflicts with too much...

Other than just centralising the text-to-int conversion for parameters,
this allows the pg_settings view to contain a list of available options
and allows an error hint to show what values are allowed.

doc/src/sgml/catalogs.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.162 2008/03/06 18:49:32 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.163 2008/03/10 12:55:13 mha Exp $ -->
 <!--
  Documentation of the system catalogs, directed toward PostgreSQL developers
  -->
@@ -6260,8 +6260,8 @@
      <row>
       <entry><structfield>vartype</structfield></entry>
       <entry><type>text</type></entry>
-      <entry>Parameter type (<literal>bool</>, <literal>integer</>,
-       <literal>real</>, or <literal>string</>)
+      <entry>Parameter type (<literal>bool</>, <literal>enum</>,
+       <literal>integer</>, <literal>real</>, or <literal>string</>)
       </entry>
      </row>
      <row>
@@ -6281,6 +6281,12 @@
       <entry>Maximum allowed value of the parameter (NULL for non-numeric
       values)</entry>
      </row>
+     <row>
+      <entry><structfield>enumvals</structfield></entry>
+      <entry><type>text</type></entry>
+      <entry>Allowed values in enum parameters (NULL for non-enum
+      values)</entry>
+     </row>
     </tbody>
    </tgroup>
   </table>

doc/src/sgml/config.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.169 2008/03/10 03:22:29 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.170 2008/03/10 12:55:13 mha Exp $ -->
 
 <chapter Id="runtime-config">
   <title>Server Configuration</title>
@@ -162,7 +162,8 @@ SET ENABLE_SEQSCAN TO OFF;
     displaying and updating session run-time parameters.  It is equivalent
     to <command>SHOW</> and <command>SET</>, but can be more convenient
     to use because it can be joined with other tables, or selected from using
-    any desired selection condition.
+    any desired selection condition. It also contains more information about
+    what values are allowed for the parameters.
    </para>
   </sect1>
 

src/backend/catalog/system_views.sql

@@ -3,7 +3,7 @@
  *
  * Copyright (c) 1996-2008, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/backend/catalog/system_views.sql,v 1.48 2008/01/01 19:45:48 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/catalog/system_views.sql,v 1.49 2008/03/10 12:55:13 mha Exp $
  */
 
 CREATE VIEW pg_roles AS 
@@ -173,7 +173,7 @@ CREATE VIEW pg_settings AS
     SELECT * 
     FROM pg_show_all_settings() AS A 
     (name text, setting text, unit text, category text, short_desc text, extra_desc text,
-     context text, vartype text, source text, min_val text, max_val text);
+     context text, vartype text, source text, min_val text, max_val text, enumvals text);
 
 CREATE RULE pg_settings_u AS 
     ON UPDATE TO pg_settings 

src/backend/tcop/postgres.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/tcop/postgres.c,v 1.543 2008/02/17 04:21:05 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/tcop/postgres.c,v 1.544 2008/03/10 12:55:13 mha Exp $
  *
  * NOTES
  *	  this is the "main" module of the postgres backend and
@@ -85,7 +85,7 @@ CommandDest whereToSendOutput = DestDebug;
 /* flag for logging end of session */
 bool		Log_disconnections = false;
 
-LogStmtLevel log_statement = LOGSTMT_NONE;
+int			log_statement = LOGSTMT_NONE;
 
 /* GUC variable for maximum stack depth (measured in kilobytes) */
 int			max_stack_depth = 100;

src/backend/utils/error/elog.c

@@ -42,7 +42,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/error/elog.c,v 1.201 2008/01/01 19:45:53 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/error/elog.c,v 1.202 2008/03/10 12:55:13 mha Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -80,7 +80,7 @@ sigjmp_buf *PG_exception_stack = NULL;
 extern bool redirection_done;
 
 /* GUC parameters */
-PGErrorVerbosity Log_error_verbosity = PGERROR_VERBOSE;
+int			Log_error_verbosity = PGERROR_VERBOSE;
 char	   *Log_line_prefix = NULL;		/* format for extra log line info */
 int			Log_destination = LOG_DESTINATION_STDERR;
 

src/include/tcop/tcopprot.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/tcop/tcopprot.h,v 1.92 2008/01/01 19:45:59 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/tcop/tcopprot.h,v 1.93 2008/03/10 12:55:13 mha Exp $
  *
  * OLD COMMENTS
  *	  This file was created so that other c files could get the two
@@ -42,7 +42,7 @@ typedef enum
 	LOGSTMT_ALL					/* log all statements */
 } LogStmtLevel;
 
-extern LogStmtLevel log_statement;
+extern int log_statement;
 
 extern List *pg_parse_and_rewrite(const char *query_string,
 					 Oid *paramTypes, int numParams);

src/include/utils/elog.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/elog.h,v 1.90 2008/01/01 19:45:59 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/utils/elog.h,v 1.91 2008/03/10 12:55:13 mha Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -283,7 +283,7 @@ typedef enum
 	PGERROR_VERBOSE				/* all the facts, ma'am */
 } PGErrorVerbosity;
 
-extern PGErrorVerbosity Log_error_verbosity;
+extern int	Log_error_verbosity;
 extern char *Log_line_prefix;
 extern int	Log_destination;
 

src/include/utils/guc.h

@@ -7,7 +7,7 @@
  * Copyright (c) 2000-2008, PostgreSQL Global Development Group
  * Written by Peter Eisentraut <peter_e@gmx.net>.
  *
- * $PostgreSQL: pgsql/src/include/utils/guc.h,v 1.90 2008/01/01 19:45:59 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/utils/guc.h,v 1.91 2008/03/10 12:55:13 mha Exp $
  *--------------------------------------------------------------------
  */
 #ifndef GUC_H
@@ -97,6 +97,7 @@ typedef const char *(*GucStringAssignHook) (const char *newval, bool doit, GucSo
 typedef bool (*GucBoolAssignHook) (bool newval, bool doit, GucSource source);
 typedef bool (*GucIntAssignHook) (int newval, bool doit, GucSource source);
 typedef bool (*GucRealAssignHook) (double newval, bool doit, GucSource source);
+typedef bool (*GucEnumAssignHook) (int newval, bool doit, GucSource source);
 
 typedef const char *(*GucShowHook) (void);
 

src/include/utils/guc_tables.h

@@ -7,7 +7,7 @@
  *
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  *
- *	  $PostgreSQL: pgsql/src/include/utils/guc_tables.h,v 1.38 2008/01/01 19:45:59 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/include/utils/guc_tables.h,v 1.39 2008/03/10 12:55:13 mha Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -24,7 +24,8 @@ enum config_type
 	PGC_BOOL,
 	PGC_INT,
 	PGC_REAL,
-	PGC_STRING
+	PGC_STRING,
+	PGC_ENUM
 };
 
 union config_var_value
@@ -33,6 +34,16 @@ union config_var_value
 	int			intval;
 	double		realval;
 	char	   *stringval;
+	int			enumval;
+};
+
+/*
+ * Enum values are made up of an array of name-value pairs
+ */
+struct config_enum_entry
+{
+	const char *name;
+	int			val;
 };
 
 /*
@@ -210,6 +221,19 @@ struct config_string
 	char	   *reset_val;
 };
 
+struct config_enum
+{
+	struct config_generic gen;
+	/* constant fields, must be set correctly in initial value: */
+	int		   *variable;
+	int			boot_val;
+	const struct config_enum_entry *options;
+	GucEnumAssignHook assign_hook;
+	GucShowHook show_hook;
+	/* variable fields, initialized at runtime: */
+	int			reset_val;
+};
+
 /* constant tables corresponding to enums above and in guc.h */
 extern const char *const config_group_names[];
 extern const char *const config_type_names[];

src/test/regress/expected/rules.out

@@ -1287,7 +1287,7 @@ SELECT viewname, definition FROM pg_views WHERE schemaname <> 'information_schem
  pg_prepared_xacts        | SELECT p.transaction, p.gid, p.prepared, u.rolname AS owner, d.datname AS database FROM ((pg_prepared_xact() p(transaction xid, gid text, prepared timestamp with time zone, ownerid oid, dbid oid) LEFT JOIN pg_authid u ON ((p.ownerid = u.oid))) LEFT JOIN pg_database d ON ((p.dbid = d.oid)));
  pg_roles                 | SELECT pg_authid.rolname, pg_authid.rolsuper, pg_authid.rolinherit, pg_authid.rolcreaterole, pg_authid.rolcreatedb, pg_authid.rolcatupdate, pg_authid.rolcanlogin, pg_authid.rolconnlimit, '********'::text AS rolpassword, pg_authid.rolvaliduntil, pg_authid.rolconfig, pg_authid.oid FROM pg_authid;
  pg_rules                 | SELECT n.nspname AS schemaname, c.relname AS tablename, r.rulename, pg_get_ruledef(r.oid) AS definition FROM ((pg_rewrite r JOIN pg_class c ON ((c.oid = r.ev_class))) LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))) WHERE (r.rulename <> '_RETURN'::name);
- pg_settings              | SELECT a.name, a.setting, a.unit, a.category, a.short_desc, a.extra_desc, a.context, a.vartype, a.source, a.min_val, a.max_val FROM pg_show_all_settings() a(name text, setting text, unit text, category text, short_desc text, extra_desc text, context text, vartype text, source text, min_val text, max_val text);
+ pg_settings              | SELECT a.name, a.setting, a.unit, a.category, a.short_desc, a.extra_desc, a.context, a.vartype, a.source, a.min_val, a.max_val, a.enumvals FROM pg_show_all_settings() a(name text, setting text, unit text, category text, short_desc text, extra_desc text, context text, vartype text, source text, min_val text, max_val text, enumvals text);
  pg_shadow                | SELECT pg_authid.rolname AS usename, pg_authid.oid AS usesysid, pg_authid.rolcreatedb AS usecreatedb, pg_authid.rolsuper AS usesuper, pg_authid.rolcatupdate AS usecatupd, pg_authid.rolpassword AS passwd, (pg_authid.rolvaliduntil)::abstime AS valuntil, pg_authid.rolconfig AS useconfig FROM pg_authid WHERE pg_authid.rolcanlogin;
  pg_stat_activity         | SELECT d.oid AS datid, d.datname, pg_stat_get_backend_pid(s.backendid) AS procpid, pg_stat_get_backend_userid(s.backendid) AS usesysid, u.rolname AS usename, pg_stat_get_backend_activity(s.backendid) AS current_query, pg_stat_get_backend_waiting(s.backendid) AS waiting, pg_stat_get_backend_xact_start(s.backendid) AS xact_start, pg_stat_get_backend_activity_start(s.backendid) AS query_start, pg_stat_get_backend_start(s.backendid) AS backend_start, pg_stat_get_backend_client_addr(s.backendid) AS client_addr, pg_stat_get_backend_client_port(s.backendid) AS client_port FROM pg_database d, (SELECT pg_stat_get_backend_idset() AS backendid) s, pg_authid u WHERE ((pg_stat_get_backend_dbid(s.backendid) = d.oid) AND (pg_stat_get_backend_userid(s.backendid) = u.oid));
  pg_stat_all_indexes      | SELECT c.oid AS relid, i.oid AS indexrelid, n.nspname AS schemaname, c.relname, i.relname AS indexrelname, pg_stat_get_numscans(i.oid) AS idx_scan, pg_stat_get_tuples_returned(i.oid) AS idx_tup_read, pg_stat_get_tuples_fetched(i.oid) AS idx_tup_fetch FROM (((pg_class c JOIN pg_index x ON ((c.oid = x.indrelid))) JOIN pg_class i ON ((i.oid = x.indexrelid))) LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))) WHERE (c.relkind = ANY (ARRAY['r'::"char", 't'::"char"]));