In the continuing saga of FE/BE protocol revisions, add reporting of

initial values and runtime changes in selected parameters.  This gets
rid of the need for an initial 'select pg_client_encoding()' query in
libpq, bringing us back to one message transmitted in each direction
for a standard connection startup.  To allow server version to be sent
using the same GUC mechanism that handles other parameters, invent the
concept of a never-settable GUC parameter: you can 'show server_version'
but it's not settable by any GUC input source.  Create 'lc_collate' and
'lc_ctype' never-settable parameters so that people can find out these
settings without need for pg_controldata.  (These side ideas were all
discussed some time ago in pgsql-hackers, but not yet implemented.)

3 files changed, 50 insertions, 56 deletions

diff --git a/src/include/commands/variable.h b/src/include/commands/variable.h
index 73687178fe8..68a0ebf7450 100644
--- a/src/include/commands/variable.h
+++ b/src/include/commands/variable.h
@@ -2,7 +2,7 @@
  * variable.h
  *		Routines for handling specialized SET variables.
  *
- * $Id: variable.h,v 1.19 2002/09/04 20:31:42 momjian Exp $
+ * $Id: variable.h,v 1.20 2003/04/25 19:45:09 tgl Exp $
  *
  */
 #ifndef VARIABLE_H
@@ -22,9 +22,6 @@ extern bool assign_random_seed(double value,
 extern const char *show_random_seed(void);
 extern const char *assign_client_encoding(const char *value,
 					   bool doit, bool interactive);
-extern const char *assign_server_encoding(const char *value,
-					   bool doit, bool interactive);
-extern const char *show_server_encoding(void);
 extern const char *assign_session_authorization(const char *value,
 							 bool doit, bool interactive);
 extern const char *show_session_authorization(void);
diff --git a/src/include/libpq/pqcomm.h b/src/include/libpq/pqcomm.h
index 4f458c51c29..6a871c7c6f6 100644
--- a/src/include/libpq/pqcomm.h
+++ b/src/include/libpq/pqcomm.h
@@ -9,7 +9,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: pqcomm.h,v 1.79 2003/04/24 21:16:44 tgl Exp $
+ * $Id: pqcomm.h,v 1.80 2003/04/25 19:45:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -106,7 +106,7 @@ typedef union SockAddr
 /* The earliest and latest frontend/backend protocol version supported. */
 
 #define PG_PROTOCOL_EARLIEST	PG_PROTOCOL(1,0)
-#define PG_PROTOCOL_LATEST		PG_PROTOCOL(3,103) /* XXX temporary value */
+#define PG_PROTOCOL_LATEST		PG_PROTOCOL(3,104) /* XXX temporary value */
 
 typedef uint32 ProtocolVersion; /* FE/BE protocol version number */
 
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index f39f0a18544..47a5eeab187 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -1,10 +1,14 @@
-/*
+/*--------------------------------------------------------------------
  * guc.h
  *
  * External declarations pertaining to backend/utils/misc/guc.c and
  * backend/utils/misc/guc-file.l
  *
- * $Id: guc.h,v 1.26 2002/11/15 00:47:22 momjian Exp $
+ * Copyright 2000-2003 by PostgreSQL Global Development Group
+ * Written by Peter Eisentraut <peter_e@gmx.net>.
+ *
+ * $Id: guc.h,v 1.27 2003/04/25 19:45:09 tgl Exp $
+ *--------------------------------------------------------------------
  */
 #ifndef GUC_H
 #define GUC_H
@@ -17,32 +21,37 @@
  * Certain options can only be set at certain times. The rules are
  * like this:
  *
+ * INTERNAL options cannot be set by the user at all, but only through
+ * internal processes ("server_version" is an example).  These are GUC
+ * variables only so they can be shown by SHOW, etc.
+ *
  * POSTMASTER options can only be set when the postmaster starts,
  * either from the configuration file or the command line.
  *
  * SIGHUP options can only be set at postmaster startup or by changing
  * the configuration file and sending the HUP signal to the postmaster
  * or a backend process. (Notice that the signal receipt will not be
- * evaluated immediately. The postmaster and the backend block at a
+ * evaluated immediately. The postmaster and the backend check it at a
  * certain point in their main loop. It's safer to wait than to read a
  * file asynchronously.)
  *
  * BACKEND options can only be set at postmaster startup, from the
- * configuration file, or with the PGOPTIONS variable from the client
- * when the connection is initiated.  Furthermore, an already-started
- * backend will ignore changes to such an option in the configuration
- * file.  The idea is that these options are fixed for a given backend
- * once it's started, but they can vary across backends.
+ * configuration file, or by client request in the connection startup
+ * packet (e.g., from libpq's PGOPTIONS variable).  Furthermore, an
+ * already-started backend will ignore changes to such an option in the
+ * configuration file.  The idea is that these options are fixed for a
+ * given backend once it's started, but they can vary across backends.
  *
  * SUSET options can be set at postmaster startup, with the SIGHUP
  * mechanism, or from SQL if you're a superuser. These options cannot
- * be set using the PGOPTIONS mechanism, because there is not check as
- * to who does this.
+ * be set in the connection startup packet, because when it is processed
+ * we don't yet know if the user is a superuser.
  *
  * USERSET options can be set by anyone any time.
  */
 typedef enum
 {
+	PGC_INTERNAL,
 	PGC_POSTMASTER,
 	PGC_SIGHUP,
 	PGC_BACKEND,
@@ -57,7 +66,8 @@ typedef enum
  * override the postmaster command line.)  Tracking the source allows us
  * to process sources in any convenient order without affecting results.
  * Sources <= PGC_S_OVERRIDE will set the default used by RESET, as well
- * as the current value.
+ * as the current value.  Note that source == PGC_S_OVERRIDE should be
+ * used when setting a PGC_INTERNAL option.
  */
 typedef enum
 {
@@ -67,11 +77,35 @@ typedef enum
 	PGC_S_ARGV = 3,				/* postmaster command line */
 	PGC_S_DATABASE = 4,			/* per-database setting */
 	PGC_S_USER = 5,				/* per-user setting */
-	PGC_S_CLIENT = 6,			/* from client (PGOPTIONS) */
+	PGC_S_CLIENT = 6,			/* from client connection request */
 	PGC_S_OVERRIDE = 7,			/* special case to forcibly set default */
 	PGC_S_SESSION = 8			/* SET command */
 } GucSource;
 
+
+/* GUC vars that are actually declared in guc.c, rather than elsewhere */
+extern bool log_statement;
+extern bool log_duration;
+extern bool Debug_print_plan;
+extern bool Debug_print_parse;
+extern bool Debug_print_rewritten;
+extern bool Debug_pretty_print;
+extern bool Explain_pretty_print;
+
+extern bool log_parser_stats;
+extern bool log_planner_stats;
+extern bool log_executor_stats;
+extern bool log_statement_stats;
+extern bool log_btree_build_stats;
+
+extern bool SQL_inheritance;
+extern bool Australian_timezones;
+
+extern int	log_min_error_statement;
+extern int	log_min_messages;
+extern int	client_min_messages;
+
+
 extern void SetConfigOption(const char *name, const char *value,
 				GucContext context, GucSource source);
 extern const char *GetConfigOption(const char *name);
@@ -80,6 +114,7 @@ extern void ProcessConfigFile(GucContext context);
 extern void InitializeGUCOptions(void);
 extern void ResetAllOptions(void);
 extern void AtEOXact_GUC(bool isCommit);
+extern void BeginReportingGUCOptions(void);
 extern void ParseLongOption(const char *string, char **name, char **value);
 extern bool set_config_option(const char *name, const char *value,
 				  GucContext context, GucSource source,
@@ -100,42 +135,4 @@ extern void ProcessGUCArray(ArrayType *array, GucSource source);
 extern ArrayType *GUCArrayAdd(ArrayType *array, const char *name, const char *value);
 extern ArrayType *GUCArrayDelete(ArrayType *array, const char *name);
 
-extern const char *assign_min_error_statement(const char *newval, bool doit,
-						   bool interactive);
-
-extern const char *assign_log_min_messages(const char *newval,
-						   bool doit, bool interactive);
-extern const char *assign_client_min_messages(const char *newval,
-						   bool doit, bool interactive);
-extern bool log_statement;
-extern bool log_duration;
-extern bool Debug_print_plan;
-extern bool Debug_print_parse;
-extern bool Debug_print_rewritten;
-extern bool Debug_pretty_print;
-
-extern bool log_parser_stats;
-extern bool log_planner_stats;
-extern bool log_executor_stats;
-extern bool log_statement_stats;
-extern bool log_btree_build_stats;
-
-extern bool Explain_pretty_print;
-
-extern bool SQL_inheritance;
-extern bool Australian_timezones;
-
-extern int	log_min_error_statement;
-extern char *log_min_error_statement_str;
-extern const char log_min_error_statement_str_default[];
-
-extern int	log_min_messages;
-extern char *log_min_messages_str;
-extern const char log_min_messages_str_default[];
-
-extern int	client_min_messages;
-extern char *client_min_messages_str;
-
-extern const char client_min_messages_str_default[];
-
 #endif   /* GUC_H */