Create a GUC variable REGEX_FLAVOR to control the type of regular

expression accepted by the regex operators, per discussion yesterday.

Along the way, reduce deadlock_timeout from PGC_POSTMASTER to PGC_SIGHUP
category.  It is probably best to insist that all backends share the same
setting, but that doesn't mean it has to be frozen at startup.

src/backend/utils/adt/regexp.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/regexp.c,v 1.44 2003/02/05 17:41:32 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/regexp.c,v 1.45 2003/02/06 20:25:33 tgl Exp $
  *
  *		Alistair Crooks added the code for the regex caching
  *		agc - cached the regular expressions used - there's a good chance
@@ -34,6 +34,10 @@
 #include "utils/builtins.h"
 
 
+/* GUC-settable flavor parameter */
+static int	regex_flavor = REG_ADVANCED;
+
+
 /*
  * We cache precompiled regular expressions using a "self organizing list"
  * structure, in which recently-used items tend to be near the front.
@@ -216,6 +220,34 @@ RE_compile_and_execute(text *text_re, unsigned char *dat, int dat_len,
 }
 
 
+/*
+ * assign_regex_flavor - GUC hook to validate and set REGEX_FLAVOR
+ */
+const char *
+assign_regex_flavor(const char *value,
+					bool doit, bool interactive)
+{
+	if (strcasecmp(value, "advanced") == 0)
+	{
+		if (doit)
+			regex_flavor = REG_ADVANCED;
+	}
+	else if (strcasecmp(value, "extended") == 0)
+	{
+		if (doit)
+			regex_flavor = REG_EXTENDED;
+	}
+	else if (strcasecmp(value, "basic") == 0)
+	{
+		if (doit)
+			regex_flavor = REG_BASIC;
+	}
+	else
+		return NULL;			/* fail */
+	return value;				/* OK */
+}
+
+
 /*
  *	interface routines called by the function manager
  */
@@ -229,7 +261,7 @@ nameregexeq(PG_FUNCTION_ARGS)
 	PG_RETURN_BOOL(RE_compile_and_execute(p,
 										  (unsigned char *) NameStr(*n),
 										  strlen(NameStr(*n)),
-										  REG_ADVANCED,
+										  regex_flavor,
 										  0, NULL));
 }
 
@@ -242,7 +274,7 @@ nameregexne(PG_FUNCTION_ARGS)
 	PG_RETURN_BOOL(!RE_compile_and_execute(p,
 										   (unsigned char *) NameStr(*n),
 										   strlen(NameStr(*n)),
-										   REG_ADVANCED,
+										   regex_flavor,
 										   0, NULL));
 }
 
@@ -255,7 +287,7 @@ textregexeq(PG_FUNCTION_ARGS)
 	PG_RETURN_BOOL(RE_compile_and_execute(p,
 										  (unsigned char *) VARDATA(s),
 										  VARSIZE(s) - VARHDRSZ,
-										  REG_ADVANCED,
+										  regex_flavor,
 										  0, NULL));
 }
 
@@ -268,7 +300,7 @@ textregexne(PG_FUNCTION_ARGS)
 	PG_RETURN_BOOL(!RE_compile_and_execute(p,
 										   (unsigned char *) VARDATA(s),
 										   VARSIZE(s) - VARHDRSZ,
-										   REG_ADVANCED,
+										   regex_flavor,
 										   0, NULL));
 }
 
@@ -288,7 +320,7 @@ nameicregexeq(PG_FUNCTION_ARGS)
 	PG_RETURN_BOOL(RE_compile_and_execute(p,
 										  (unsigned char *) NameStr(*n),
 										  strlen(NameStr(*n)),
-										  REG_ICASE | REG_ADVANCED,
+										  regex_flavor | REG_ICASE,
 										  0, NULL));
 }
 
@@ -301,7 +333,7 @@ nameicregexne(PG_FUNCTION_ARGS)
 	PG_RETURN_BOOL(!RE_compile_and_execute(p,
 										   (unsigned char *) NameStr(*n),
 										   strlen(NameStr(*n)),
-										   REG_ICASE | REG_ADVANCED,
+										   regex_flavor | REG_ICASE,
 										   0, NULL));
 }
 
@@ -314,7 +346,7 @@ texticregexeq(PG_FUNCTION_ARGS)
 	PG_RETURN_BOOL(RE_compile_and_execute(p,
 										  (unsigned char *) VARDATA(s),
 										  VARSIZE(s) - VARHDRSZ,
-										  REG_ICASE | REG_ADVANCED,
+										  regex_flavor | REG_ICASE,
 										  0, NULL));
 }
 
@@ -327,7 +359,7 @@ texticregexne(PG_FUNCTION_ARGS)
 	PG_RETURN_BOOL(!RE_compile_and_execute(p,
 										   (unsigned char *) VARDATA(s),
 										   VARSIZE(s) - VARHDRSZ,
-										   REG_ICASE | REG_ADVANCED,
+										   regex_flavor | REG_ICASE,
 										   0, NULL));
 }
 
@@ -353,7 +385,7 @@ textregexsubstr(PG_FUNCTION_ARGS)
 	match = RE_compile_and_execute(p,
 								   (unsigned char *) VARDATA(s),
 								   VARSIZE(s) - VARHDRSZ,
-								   REG_ADVANCED,
+								   regex_flavor,
 								   2, pmatch);
 
 	/* match? then return the substring matching the pattern */

src/backend/utils/misc/guc.c

@@ -5,7 +5,7 @@
  * command, configuration file, and command line options.
  * See src/backend/utils/misc/README for more information.
  *
- * $Header: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v 1.113 2003/01/28 18:04:02 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v 1.114 2003/02/06 20:25:33 tgl Exp $
  *
  * Copyright 2000 by PostgreSQL Global Development Group
  * Written by Peter Eisentraut <peter_e@gmx.net>.
@@ -127,6 +127,7 @@ static double phony_random_seed;
 static char *client_encoding_string;
 static char *datestyle_string;
 static char *default_iso_level_string;
+static char *regex_flavor_string;
 static char *server_encoding_string;
 static char *session_authorization_string;
 static char *timezone_string;
@@ -568,7 +569,7 @@ static struct config_int
 	},
 
 	{
-		{"deadlock_timeout", PGC_POSTMASTER}, &DeadlockTimeout,
+		{"deadlock_timeout", PGC_SIGHUP}, &DeadlockTimeout,
 		1000, 0, INT_MAX, NULL, NULL
 	},
 
@@ -818,6 +819,11 @@ static struct config_string
 		"C", locale_time_assign, NULL
 	},
 
+	{
+		{"regex_flavor", PGC_USERSET}, &regex_flavor_string,
+		"advanced", assign_regex_flavor, NULL
+	},
+
 	{
 		{"search_path", PGC_USERSET, GUC_LIST_INPUT | GUC_LIST_QUOTE},
 		&namespace_search_path,

src/backend/utils/misc/postgresql.conf.sample

@@ -208,6 +208,7 @@
 #max_expr_depth = 10000		# min 10
 #max_files_per_process = 1000	# min 25
 #password_encryption = true
+#regex_flavor = advanced	# advanced, extended, or basic
 #sql_inheritance = true
 #transform_null_equals = false
 #statement_timeout = 0		# 0 is disabled, in milliseconds