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Make configuration parameters fall back to their default values when they 

are removed from the configuration file.

Joachim Wieland
This commit is contained in:
Peter Eisentraut 2007-04-21 20:02:41 +00:00
parent adf7788c5e
commit b7edb568bd
3 changed files with 259 additions and 38 deletions
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158
src/backend/utils/misc/guc-file.l
View File

@ -4,7 +4,7 @@
*
* Copyright (c) 2000-2007, PostgreSQL Global Development Group
*
* $PostgreSQL: pgsql/src/backend/utils/misc/guc-file.l,v 1.49 2007/03/13 14:32:25 petere Exp $
* $PostgreSQL: pgsql/src/backend/utils/misc/guc-file.l,v 1.50 2007/04/21 20:02:40 petere Exp $
*/
%{
@ -116,6 +116,9 @@ ProcessConfigFile(GucContext context)
{
int elevel;
struct name_value_pair *item, *head, *tail;
int i;
bool *in_conffile = NULL;
const char *var;
Assert(context == PGC_POSTMASTER || context == PGC_SIGHUP);
@ -140,19 +143,158 @@ 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;
}
/* If we got here all the options checked out okay, so apply them. */
/*
* 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)
{
set_config_option(item->name, item->value, context,
PGC_S_FILE, false, true);
/*
* 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] && 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);
cleanup_list:
free(in_conffile);
free_name_value_list(head);
}
@ -312,14 +454,14 @@ ParseConfigFile(const char *config_file, const char *calling_file,
{
pfree(opt_name);
pfree(opt_value);
/* we assume error message was logged already */
/* We assume the error message was logged already. */
OK = false;
goto cleanup_exit;
}
pfree(opt_name);
pfree(opt_value);
}
else
if (pg_strcasecmp(opt_name, "include") != 0)
{
/* append to list */
struct name_value_pair *item;

128
src/backend/utils/misc/guc.c
View File

@ -10,7 +10,7 @@
* Written by Peter Eisentraut <peter_e@gmx.net>.
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.386 2007/04/18 16:44:18 alvherre Exp $
* $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.387 2007/04/21 20:02:40 petere Exp $
*
*--------------------------------------------------------------------
*/
@ -2481,7 +2481,8 @@ set_string_field(struct config_string * conf, char **field, char *newval)
if (oldval == NULL ||
oldval == *(conf->variable) ||
oldval == conf->reset_val ||
oldval == conf->tentative_val)
oldval == conf->tentative_val ||
oldval == conf->boot_val)
return;
for (stack = conf->gen.stack; stack; stack = stack->prev)
{
@ -2504,7 +2505,8 @@ string_field_used(struct config_string * conf, char *strval)
if (strval == *(conf->variable) ||
strval == conf->reset_val ||
strval == conf->tentative_val)
strval == conf->tentative_val ||
strval == conf->boot_val)
return true;
for (stack = conf->gen.stack; stack; stack = stack->prev)
{
@ -2673,6 +2675,18 @@ add_guc_variable(struct config_generic * var, int elevel)
return true;
}
static int
guc_get_index(const char *name)
{
int i;
for (i = 0; i < num_guc_variables; i++)
if (strcasecmp(name, guc_variables[i]->name) == 0)
return i;
return -1;
}
/*
* Create and add a placeholder variable. It's presumed to belong
* to a valid custom variable class at this point.
@ -2851,39 +2865,39 @@ InitializeGUCOptions(void)
struct config_bool *conf = (struct config_bool *) gconf;
if (conf->assign_hook)
if (!(*conf->assign_hook) (conf->reset_val, true,
if (!(*conf->assign_hook) (conf->boot_val, true,
PGC_S_DEFAULT))
elog(FATAL, "failed to initialize %s to %d",
conf->gen.name, (int) conf->reset_val);
*conf->variable = conf->reset_val;
conf->gen.name, (int) conf->boot_val);
*conf->variable = conf->reset_val = conf->boot_val;
break;
}
case PGC_INT:
{
struct config_int *conf = (struct config_int *) gconf;
Assert(conf->reset_val >= conf->min);
Assert(conf->reset_val <= conf->max);
Assert(conf->boot_val >= conf->min);
Assert(conf->boot_val <= conf->max);
if (conf->assign_hook)
if (!(*conf->assign_hook) (conf->reset_val, true,
if (!(*conf->assign_hook) (conf->boot_val, true,
PGC_S_DEFAULT))
elog(FATAL, "failed to initialize %s to %d",
conf->gen.name, conf->reset_val);
*conf->variable = conf->reset_val;
conf->gen.name, conf->boot_val);
*conf->variable = conf->reset_val = conf->boot_val;
break;
}
case PGC_REAL:
{
struct config_real *conf = (struct config_real *) gconf;
Assert(conf->reset_val >= conf->min);
Assert(conf->reset_val <= conf->max);
Assert(conf->boot_val >= conf->min);
Assert(conf->boot_val <= conf->max);
if (conf->assign_hook)
if (!(*conf->assign_hook) (conf->reset_val, true,
if (!(*conf->assign_hook) (conf->boot_val, true,
PGC_S_DEFAULT))
elog(FATAL, "failed to initialize %s to %g",
conf->gen.name, conf->reset_val);
*conf->variable = conf->reset_val;
conf->gen.name, conf->boot_val);
*conf->variable = conf->reset_val = conf->boot_val;
break;
}
case PGC_STRING:
@ -3945,6 +3959,13 @@ set_config_option(const char *name, const char *value,
return false;
}
/*
* Do not replace a value that has been set on the command line by a SIGHUP
* reload
*/
if (context == PGC_SIGHUP && record->source == PGC_S_ARGV)
return true;
/*
* Check if the option can be set at this time. See guc.h for the precise
* rules. Note that we don't want to throw errors if we're in the SIGHUP
@ -4040,19 +4061,26 @@ set_config_option(const char *name, const char *value,
}
/*
* Should we set reset/stacked values? (If so, the behavior is not
* transactional.)
* Should we set reset/stacked values? (If so, the behavior is not
* transactional.) This is done either when we get a default
* value from the database's/user's/client's default settings or
* when we reset a value to its default.
*/
makeDefault = changeVal && (source <= PGC_S_OVERRIDE) && (value != NULL);
makeDefault = changeVal && (source <= PGC_S_OVERRIDE)
&& ((value != NULL) || source == PGC_S_DEFAULT);
/*
* Ignore attempted set if overridden by previously processed setting.
* However, if changeVal is false then plow ahead anyway since we are
* trying to find out if the value is potentially good, not actually use
* it. Also keep going if makeDefault is true, since we may want to set
* the reset/stacked values even if we can't set the variable itself.
* Ignore attempted set if overridden by previously processed
* setting. However, if changeVal is false then plow ahead anyway
* since we are trying to find out if the value is potentially
* good, not actually use it. Also keep going if makeDefault is
* true, since we may want to set the reset/stacked values even if
* we can't set the variable itself. There's one exception to
* this rule: if we want to apply the default value to variables
* that were removed from the configuration file. This is
* indicated by source == PGC_S_DEFAULT.
*/
if (record->source > source)
if (record->source > source && source != PGC_S_DEFAULT)
{
if (changeVal && !makeDefault)
{
@ -4084,6 +4112,14 @@ set_config_option(const char *name, const char *value,
return false;
}
}
/*
* If value == NULL and source == PGC_S_DEFAULT then
* we reset some value to its default (removed from
* configuration file).
*/
else if (source == PGC_S_DEFAULT)
newval = conf->boot_val;
/* else we handle a "RESET varname" command */
else
{
newval = conf->reset_val;
@ -4168,6 +4204,14 @@ set_config_option(const char *name, const char *value,
return false;
}
}
/*
* If value == NULL and source == PGC_S_DEFAULT then
* we reset some value to its default (removed from
* configuration file).
*/
else if (source == PGC_S_DEFAULT)
newval = conf->boot_val;
/* else we handle a "RESET varname" command */
else
{
newval = conf->reset_val;
@ -4252,6 +4296,14 @@ set_config_option(const char *name, const char *value,
return false;
}
}
/*
* If value == NULL and source == PGC_S_DEFAULT then
* we reset some value to its default (removed from
* configuration file).
*/
else if (source == PGC_S_DEFAULT)
newval = conf->boot_val;
/* else we handle a "RESET varname" command */
else
{
newval = conf->reset_val;
@ -4330,6 +4382,23 @@ set_config_option(const char *name, const char *value,
if (conf->gen.flags & GUC_IS_NAME)
truncate_identifier(newval, strlen(newval), true);
}
/*
* If value == NULL and source == PGC_S_DEFAULT then
* we reset some value to its default (removed from
* configuration file).
*/
else if (source == PGC_S_DEFAULT)
{
if (conf->boot_val == NULL)
newval = NULL;
else
{
newval = guc_strdup(elevel, conf->boot_val);
if (newval == NULL)
return false;
}
}
/* else we handle a "RESET varname" command */
else if (conf->reset_val)
{
/*
@ -6404,6 +6473,13 @@ assign_custom_variable_classes(const char *newval, bool doit, GucSource source)
int c;
StringInfoData buf;
/*
* Resetting custom_variable_classes by removing it from the
* configuration file will lead to newval = NULL
*/
if (newval == NULL)
return guc_strdup(ERROR, "");
initStringInfo(&buf);
while ((c = *cp++) != 0)
{
@ -6448,7 +6524,7 @@ assign_custom_variable_classes(const char *newval, bool doit, GucSource source)
if (buf.len == 0)
newval = NULL;
else if (doit)
newval = strdup(buf.data);
newval = guc_strdup(ERROR, buf.data);
pfree(buf.data);
return newval;

11
src/include/utils/guc_tables.h
View File

@ -7,7 +7,7 @@
*
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
*
* $PostgreSQL: pgsql/src/include/utils/guc_tables.h,v 1.32 2007/03/13 14:32:25 petere Exp $
* $PostgreSQL: pgsql/src/include/utils/guc_tables.h,v 1.33 2007/04/21 20:02:41 petere Exp $
*
*-------------------------------------------------------------------------
*/
@ -154,10 +154,11 @@ struct config_bool
/* these fields must be set correctly in initial value: */
/* (all but reset_val are constants) */
bool *variable;
bool reset_val;
bool boot_val;
GucBoolAssignHook assign_hook;
GucShowHook show_hook;
/* variable fields, initialized at runtime: */
bool reset_val;
bool tentative_val;
};
@ -167,12 +168,13 @@ struct config_int
/* these fields must be set correctly in initial value: */
/* (all but reset_val are constants) */
int *variable;
int reset_val;
int boot_val;
int min;
int max;
GucIntAssignHook assign_hook;
GucShowHook show_hook;
/* variable fields, initialized at runtime: */
int reset_val;
int tentative_val;
};
@ -182,12 +184,13 @@ struct config_real
/* these fields must be set correctly in initial value: */
/* (all but reset_val are constants) */
double *variable;
double reset_val;
double boot_val;
double min;
double max;
GucRealAssignHook assign_hook;
GucShowHook show_hook;
/* variable fields, initialized at runtime: */
double reset_val;
double tentative_val;
};