Reverted waiting for further fixes:

Make configuration parameters fall back to their default values when they
are removed from the configuration file.

Joachim Wieland

Author: petere

src/backend/access/transam/xact.c

@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.236 2007/03/13 00:33:38 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.237 2007/03/13 14:32:25 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1513,9 +1513,6 @@ CommitTransaction(void)
 	/* NOTIFY commit must come before lower-level cleanup */
 	AtCommit_Notify();
 
-	/* GUC processing could abort transaction */
-	AtEOXact_GUC(true, false);
-
 	/*
 	 * Update flat files if we changed pg_database, pg_authid or
 	 * pg_auth_members.  This should be the last step before commit.
@@ -1626,6 +1623,7 @@ CommitTransaction(void)
 	/* Check we've released all catcache entries */
 	AtEOXact_CatCache(true);
 
+	AtEOXact_GUC(true, false);
 	AtEOXact_SPI(true);
 	AtEOXact_on_commit_actions(true);
 	AtEOXact_Namespace(true);

src/backend/utils/misc/guc-file.l

@@ -4,7 +4,7 @@
  *
  * Copyright (c) 2000-2007, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/backend/utils/misc/guc-file.l,v 1.48 2007/03/12 22:09:27 petere Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/misc/guc-file.l,v 1.49 2007/03/13 14:32:25 petere Exp $
  */
 
 %{
@@ -54,8 +54,6 @@ static bool ParseConfigFile(const char *config_file, const char *calling_file,
 static void free_name_value_list(struct name_value_pair * list);
 static char *GUC_scanstr(const char *s);
 
-static char *custom_variable_classes_backup;
-
 %}
 
 %option 8bit
@@ -118,10 +116,6 @@ ProcessConfigFile(GucContext context)
 {
 	int			elevel;
 	struct name_value_pair *item, *head, *tail;
-	int						i;
-	bool				   *in_conffile = NULL;
-	const char			   *var;
-	bool					success = false;
 
 	Assert(context == PGC_POSTMASTER || context == PGC_SIGHUP);
 
@@ -138,18 +132,6 @@ ProcessConfigFile(GucContext context)
 
 	head = tail = NULL;
 
-	/*
-	 * We do not know whether we will read the configuration file
-	 * without error.  If we encounter an error we have to restore the
-	 * previous value of the custom_variable_classes variable for
-	 * consistency.  Therefore we have to save its value.
-	 */
-	var = GetConfigOption("custom_variable_classes");
-	if (var)
-		custom_variable_classes_backup = pstrdup(var);
-	set_config_option("custom_variable_classes", NULL, context,
-					  PGC_S_DEFAULT, false, true);
-
 	if (!ParseConfigFile(ConfigFileName, NULL,
 						 0, context, elevel,
 						 &head, &tail))
@@ -158,198 +140,20 @@ ProcessConfigFile(GucContext context)
 	/* Check if all options are valid */
 	for (item = head; item; item = item->next)
 	{
-		char *sep = strchr(item->name, GUC_QUALIFIER_SEPARATOR);
-		if (sep && !is_custom_class(item->name, sep - item->name))
-		{
-			ereport(elevel,
-				(errcode(ERRCODE_UNDEFINED_OBJECT),
-				 errmsg("unrecognized configuration parameter \"%s\"",
-						item->name)));
-			goto cleanup_list;
-		}
-
 		if (!set_config_option(item->name, item->value, context,
 							   PGC_S_FILE, false, false))
 			goto cleanup_list;
 	}
 
-
-	/*
-	 * Mark all variables as not showing up in the config file.  The
-	 * allocation has to take place after ParseConfigFile() since this
-	 * function can change num_guc_variables due to custom variables.
-	 * It would be easier to add a new field or status bit to struct
-	 * conf_generic, but that way we would expose internal information
-	 * that is just needed here in the following few lines.  The price
-	 * to pay for this separation are a few more loops over the set of
-	 * configuration options, but those are expected to be rather few
-	 * and we only have to pay the cost at SIGHUP.  We initialize
-	 * in_conffile only here because set_config_option() makes
-	 * guc_variables grow with custom variables.
-	 */
-	in_conffile = guc_malloc(elevel, num_guc_variables * sizeof(bool));
-	if (!in_conffile)
-		goto cleanup_list;
-	for (i = 0; i < num_guc_variables; i++)
-		in_conffile[i] = false;
-
-	for (item = head; item; item = item->next)
-	{
-		/*
-		 * After set_config_option() the variable name item->name is
-		 * known to exist.
-		 */
-		Assert(guc_get_index(item->name) >= 0);
-		in_conffile[guc_get_index(item->name)] = true;
-	}
-
-	for (i = 0; i < num_guc_variables; i++)
-	{
-		struct config_generic *gconf = guc_variables[i];
-		if (!in_conffile[i] && strchr(gconf->name, GUC_QUALIFIER_SEPARATOR))
-		{
-			/* handle custom variables here */
-			int j;
-
-			/*
-			 * guc_delete_variable will re-sort the array of
-			 * configuration options and decrease num_guc_variables by
-			 * one.
-			 */
-			guc_delete_custom_variable(gconf->name);
-
-			/*
-			 * Since the array is always sorted we just have to shift
-			 * all boolean values after position i by one position to
-			 * the left.
-			 */
-			for (j = i; j < num_guc_variables; j++)
-				in_conffile[j] = in_conffile[j+1];
-
-			/*
-			 * Decrease the loop variable to re-test the entry at the
-			 * current position that is now a different one.
-			 */
-			i--;
-
-			continue;
-		}
-		else if (!in_conffile[i] && gconf->source == PGC_S_FILE)
-		{
-			if (gconf->context < PGC_SIGHUP)
-				ereport(elevel,
-					(errcode(ERRCODE_CANT_CHANGE_RUNTIME_PARAM),
-							 errmsg("parameter \"%s\" cannot be changed after server start; configuration file change ignored",
-									gconf->name)));
-			else
-			{
-					/* prepare */
-					GucStack   *stack;
-					if (gconf->reset_source == PGC_S_FILE)
-						gconf->reset_source = PGC_S_DEFAULT;
-					for (stack = gconf->stack; stack; stack = stack->prev)
-						if (stack->source == PGC_S_FILE)
-							stack->source = PGC_S_DEFAULT;
-					/* apply the default */
-					set_config_option(gconf->name, NULL, context,
-									  PGC_S_DEFAULT, false, true);
-			}
-		}
-		else if (!in_conffile[i] && gconf->reset_source == PGC_S_FILE)
-		{
-			/*------
-			 * Change the reset_val to default_val.  Here's an
-			 * example: In the configuration file we have
-			 *
-			 * seq_page_cost = 3.00
-			 *
-			 * Now we execute in a session
-			 *
-			 * SET seq_page_cost TO 4.00;
-			 *
-			 * Then we remove this option from the configuration file
-			 * and send SIGHUP. Now when you execute
-			 *
-			 * RESET seq_page_cost;
-			 *
-			 * it should fall back to 1.00 (the default value for
-			 * seq_page_cost) and not to 3.00 (which is the current
-			 * reset_val).
-			 */
-
-			switch (gconf->vartype)
-			{
-				case PGC_BOOL:
-					{
-						struct config_bool *conf;
-						conf = (struct config_bool *) gconf;
-						conf->reset_val = conf->boot_val;
-						break;
-					}
-				case PGC_INT:
-					{
-						struct config_int *conf;
-						conf = (struct config_int *) gconf;
-						conf->reset_val = conf->boot_val;
-						break;
-					}
-				case PGC_REAL:
-					{
-						struct config_real *conf;
-						conf = (struct config_real *) gconf;
-						conf->reset_val = conf->boot_val;
-						break;
-					}
-				case PGC_STRING:
-					{
-						struct config_string   *conf;
-						conf = (struct config_string *) gconf;
-						/*
-						 * We can cast away the const here because we
-						 * won't free the address.  It is protected by
-						 * set_string_field() and string_field_used().
-						 */
-						conf->reset_val = (char *) conf->boot_val;
-						break;
-					}
-			}
-		}
-	}
-
 	/* If we got here all the options checked out okay, so apply them. */
 	for (item = head; item; item = item->next)
+	{
 		set_config_option(item->name, item->value, context,
 						  PGC_S_FILE, false, true);
-
-	/*
-	 * Reset variables to the value of environment variables
-	 * (PGC_S_ENV_VAR overrules PGC_S_FILE).  PGPORT is ignored,
-	 * because it cannot be changed without restart.
-	 */
-	var = getenv("PGDATESTYLE");
-	if (var != NULL)
-		set_config_option("datestyle", var, context,
-						  PGC_S_ENV_VAR, false, true);
-
-	var = getenv("PGCLIENTENCODING");
-	if (var != NULL)
-		set_config_option("client_encoding", var, context,
-						  PGC_S_ENV_VAR, false, true);
-
-	success = true;
+	}
 
  cleanup_list:
-	free(in_conffile);
 	free_name_value_list(head);
-	if (!success)
-		set_config_option("custom_variable_classes",
-						  custom_variable_classes_backup,
-						  context, PGC_S_FILE, false, true);
-	if (custom_variable_classes_backup)
-	{
-		pfree(custom_variable_classes_backup);
-		custom_variable_classes_backup = NULL;
-	}
 }
 
 
@@ -508,14 +312,14 @@ ParseConfigFile(const char *config_file, const char *calling_file,
 			{
 				pfree(opt_name);
 				pfree(opt_value);
-
-				/* We assume the error message was logged already. */
+				/* we assume error message was logged already */
 				OK = false;
 				goto cleanup_exit;
 			}
+			pfree(opt_name);
+			pfree(opt_value);
 		}
-
-		if (pg_strcasecmp(opt_name, "include") != 0)
+		else
 		{
 			/* append to list */
 			struct name_value_pair *item;