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Postgres FD Implementation
Commit f84308f1 authored by Peter Eisentraut's avatar Peter Eisentraut
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Make configuration parameters fall back to their default values when they 

are removed from the configuration file.

Joachim Wieland
parent eee22892
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Showing with 441 additions and 40 deletions
src/backend/access/transam/xact.c
View file @ f84308f1
......@@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.234 2007/02/09 03:35:33 tgl Exp $
* $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.235 2007/03/12 22:09:27 petere Exp $
*
*-------------------------------------------------------------------------
*/
......@@ -1513,6 +1513,9 @@ 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.
......@@ -1623,7 +1626,6 @@ 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
View file @ f84308f1
......@@ -4,7 +4,7 @@
*
* Copyright (c) 2000-2007, PostgreSQL Global Development Group
*
* $PostgreSQL: pgsql/src/backend/utils/misc/guc-file.l,v 1.47 2007/02/10 14:58:55 petere Exp $
* $PostgreSQL: pgsql/src/backend/utils/misc/guc-file.l,v 1.48 2007/03/12 22:09:27 petere Exp $
*/
%{
......@@ -54,6 +54,8 @@ 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
......@@ -116,6 +118,10 @@ 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);
......@@ -132,6 +138,18 @@ 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))
......@@ -140,20 +158,198 @@ 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)
{
/*
* 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;
}
}
......@@ -312,14 +508,14 @@ 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;
......
src/backend/utils/misc/guc.c
View file @ f84308f1
......@@ -10,7 +10,7 @@
* Written by Peter Eisentraut <peter_e@gmx.net>.
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.379 2007/03/06 02:06:14 momjian Exp $
* $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.380 2007/03/12 22:09:28 petere Exp $
*
*--------------------------------------------------------------------
*/
......@@ -2439,7 +2439,8 @@ 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)
{
......@@ -2462,7 +2463,8 @@ 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)
{
......@@ -2631,6 +2633,105 @@ 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;
}
static void
guc_delete_variable(const char *name)
{
struct config_generic *gen;
int idx;
GucStack *stack, *prev;
struct config_string *conf;
idx = guc_get_index(name);
Assert(idx >= 0);
gen = guc_variables[idx];
/*
* Even though this function could delete other types of variables as well,
* at the moment we only call it for custom variables that always have type
* string.
*/
Assert(gen->group == CUSTOM_OPTIONS);
Assert(gen->vartype == PGC_STRING);
conf = (struct config_string *) gen;
set_string_field(conf, &conf->reset_val, NULL);
set_string_field(conf, &conf->tentative_val, NULL);
for (stack = conf->gen.stack; stack; stack = prev)
{
set_string_field(conf, &stack->tentative_val.stringval, NULL);
set_string_field(conf, &stack->value.stringval, NULL);
prev = stack->prev;
pfree(stack);
}
/* no pfree() here, gen has been allocated via guc_malloc */
free(gen);
guc_variables[idx] = guc_variables[num_guc_variables - 1];
num_guc_variables--;
qsort((void *) guc_variables, num_guc_variables,
sizeof(struct config_generic *), guc_var_compare);
}
static void
guc_delete_custom_variable(const char *name)
{
struct config_generic *gen;
struct config_string *conf;
int idx;
idx = guc_get_index(name);
Assert(idx >= 0);
gen = guc_variables[idx];
Assert(gen->group == CUSTOM_OPTIONS);
Assert(gen->vartype == PGC_STRING);
conf = (struct config_string *) gen;
/*
* Here we check whether it is safe to really delete the variable
* or if we have to wait for the end of the transaction. We do
* not remove the physical entry of a custom variable if it has
* been SET to another value in the transaction but has been
* removed from the configuration file.
*/
if (gen->stack)
{
/*
* Make sure this custom variable (which has a definition in
* the configuration file) behaves as any other custom
* variable from now on. We have deleted its former
* definition; that's why "RESET foo.bar" should not fall back
* to this deleted definition from the configuration file.
* The analogy is that any other custom variable that gets
* introduced in a session has no reset value either. And a
* variable that has been SET within a transaction and has
* then been deleted from the configuration file should behave
* as if it had been introduced in the session.
*/
Assert(gen->vartype == PGC_STRING);
gen->reset_source = PGC_S_DEFAULT;
set_string_field(conf, &conf->reset_val, NULL);
}
else
guc_delete_variable(name);
}
/*
* Create and add a placeholder variable. It's presumed to belong
* to a valid custom variable class at this point.
......@@ -2809,39 +2910,39 @@ 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:
......@@ -3296,8 +3397,25 @@ push_old_value(struct config_generic * gconf)
}
}
/*
/*------
* Do GUC processing at transaction or subtransaction commit or abort.
*
* GUC can abort the transaction in exactly one case, namely when you
* delete a custom variable class while a still-open transaction has
* SET a custom variable within this class.
*
* Consider the following example. In the configuration file we could
* have:
*
* custom_variable_classes = "foo"
*
* begin;
* set foo.bar to 1;
* <delete foo.bar from configuration file and send SIGHUP>
* commit;
*
* This will result in an error because foo.bar is no longer available
* but commit would have to guarantee that the value is preserved.
*/
void
AtEOXact_GUC(bool isCommit, bool isSubXact)
......@@ -3335,6 +3453,33 @@ AtEOXact_GUC(bool isCommit, bool isSubXact)
continue;
Assert(stack->nest_level == my_level);
if (!isSubXact && gconf->group == CUSTOM_OPTIONS)
{
char *dot = strchr(gconf->name, GUC_QUALIFIER_SEPARATOR);
Assert(dot != NULL);
if (!is_custom_class(gconf->name, dot - gconf->name))
{
if (!isCommit)
{
/* We do not commit the transaction. Delete the variable. */
guc_delete_variable(gconf->name);
/* Call the loop with the same i again, which is
* the next variable. */
i--;
continue;
}
else
{
/* We commit the transaction. Throw an error that
* the respective custom class does not exist. */
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("no valid custom variable class available for "
"parameter \"%s\"", gconf->name)));
}
}
}
/*
* We will pop the stack entry. Start by restoring outer xact status
* (since we may want to modify it below). Be careful to use
......@@ -3998,19 +4143,26 @@ 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)
{
......@@ -4042,6 +4194,14 @@ 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;
......@@ -4126,6 +4286,14 @@ 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;
......@@ -4210,6 +4378,14 @@ 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;
......@@ -4288,6 +4464,23 @@ 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)
{
/*
......@@ -6304,6 +6497,13 @@ 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)
{
......@@ -6348,7 +6548,7 @@ 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;
......
src/include/utils/guc_tables.h
View file @ f84308f1
......@@ -7,7 +7,7 @@
*
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
*
* $PostgreSQL: pgsql/src/include/utils/guc_tables.h,v 1.30 2007/01/05 22:19:59 momjian Exp $
* $PostgreSQL: pgsql/src/include/utils/guc_tables.h,v 1.31 2007/03/12 22:09:28 petere Exp $
*
*-------------------------------------------------------------------------
*/
......@@ -154,11 +154,12 @@ 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 tentative_val;
bool reset_val;
};
struct config_int
......@@ -167,13 +168,14 @@ 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 tentative_val;
int reset_val;
};
struct config_real
......@@ -182,13 +184,14 @@ 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 tentative_val;
double reset_val;
};
struct config_string
......
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