mirror/postgresql
2
0
Fork 0
mirror of https://git.postgresql.org/git/postgresql.git synced 2024-12-09 08:10:09 +08:00
Code Issues Packages Projects Releases Wiki Activity

Add an optional missing_ok argument to SQL function current_setting().

Browse Source 
This allows convenient checking for existence of a GUC from SQL, which is
particularly useful when dealing with custom variables.

David Christensen, reviewed by Jeevan Chalke
This commit is contained in:
Tom Lane 2015-07-02 16:40:55 -04:00
parent 7261172430
commit 10fb48d66d
9 changed files with 101 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
contrib/tsearch2/tsearch2.c
View File

@ -363,7 +363,7 @@ tsa_tsearch2(PG_FUNCTION_ARGS)
tgargs[i + 1] = trigger->tgargs[i];
tgargs[1] = pstrdup(GetConfigOptionByName("default_text_search_config",
NULL));
NULL, false));
tgargs_old = trigger->tgargs;
trigger->tgargs = tgargs;
trigger->tgnargs++;

7
doc/src/sgml/func.sgml
View File

@ -16444,7 +16444,7 @@ SELECT collation for ('foo' COLLATE "de_DE");
<indexterm>
<primary>current_setting</primary>
</indexterm>
<literal><function>current_setting(<parameter>setting_name</parameter>)</function></literal>
<literal><function>current_setting(<parameter>setting_name</parameter> [, <parameter>missing_ok</parameter> ])</function></literal>
</entry>
<entry><type>text</type></entry>
<entry>get current value of setting</entry>
@ -16492,6 +16492,11 @@ SELECT current_setting('datestyle');
ISO, MDY
(1 row)
</programlisting>
If there is no setting named <parameter>setting_name</parameter>,
<function>current_setting</function> throws an error
unless <parameter>missing_ok</parameter> is supplied and is
<literal>true</literal>.
</para>
<para>

53
src/backend/utils/misc/guc.c
View File

@ -7131,7 +7131,7 @@ ExtractSetVariableArgs(VariableSetStmt *stmt)
case VAR_SET_VALUE:
return flatten_set_variable_args(stmt->name, stmt->args);
case VAR_SET_CURRENT:
return GetConfigOptionByName(stmt->name, NULL);
return GetConfigOptionByName(stmt->name, NULL, false);
default:
return NULL;
}
@ -7200,7 +7200,7 @@ set_config_by_name(PG_FUNCTION_ARGS)
true, 0, false);
/* get the new current value */
new_value = GetConfigOptionByName(name, NULL);
new_value = GetConfigOptionByName(name, NULL, false);
/* Convert return string to text */
PG_RETURN_TEXT_P(cstring_to_text(new_value));
@ -7627,7 +7627,7 @@ GetPGVariableResultDesc(const char *name)
const char *varname;
/* Get the canonical spelling of name */
(void) GetConfigOptionByName(name, &varname);
(void) GetConfigOptionByName(name, &varname, false);
/* need a tuple descriptor representing a single TEXT column */
tupdesc = CreateTemplateTupleDesc(1, false);
@ -7650,7 +7650,7 @@ ShowGUCConfigOption(const char *name, DestReceiver *dest)
char *value;
/* Get the value and canonical spelling of name */
value = GetConfigOptionByName(name, &varname);
value = GetConfigOptionByName(name, &varname, false);
/* need a tuple descriptor representing a single TEXT column */
tupdesc = CreateTemplateTupleDesc(1, false);
@ -7734,19 +7734,30 @@ ShowAllGUCConfig(DestReceiver *dest)
}
/*
* Return GUC variable value by name; optionally return canonical
* form of name. Return value is palloc'd.
* Return GUC variable value by name; optionally return canonical form of
* name. If the GUC is unset, then throw an error unless missing_ok is true,
* in which case return NULL. Return value is palloc'd (but *varname isn't).
*/
char *
GetConfigOptionByName(const char *name, const char **varname)
GetConfigOptionByName(const char *name, const char **varname, bool missing_ok)
{
struct config_generic *record;
record = find_option(name, false, ERROR);
if (record == NULL)
{
if (missing_ok)
{
if (varname)
*varname = NULL;
return NULL;
}
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("unrecognized configuration parameter \"%s\"", name)));
}
if ((record->flags & GUC_SUPERUSER_ONLY) && !superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
@ -8033,14 +8044,34 @@ GetNumConfigOptions(void)
Datum
show_config_by_name(PG_FUNCTION_ARGS)
{
char *varname;
char *varname = TextDatumGetCString(PG_GETARG_DATUM(0));
char *varval;
/* Get the GUC variable name */
varname = TextDatumGetCString(PG_GETARG_DATUM(0));
/* Get the value */
varval = GetConfigOptionByName(varname, NULL, false);
/* Convert to text */
PG_RETURN_TEXT_P(cstring_to_text(varval));
}
/*
* show_config_by_name_missing_ok - equiv to SHOW X command but implemented as
* a function. If X does not exist, suppress the error and just return NULL
* if missing_ok is TRUE.
*/
Datum
show_config_by_name_missing_ok(PG_FUNCTION_ARGS)
{
char *varname = TextDatumGetCString(PG_GETARG_DATUM(0));
bool missing_ok = PG_GETARG_BOOL(1);
char *varval;
/* Get the value */
varval = GetConfigOptionByName(varname, NULL);
varval = GetConfigOptionByName(varname, NULL, missing_ok);
/* return NULL if no such variable */
if (varval == NULL)
PG_RETURN_NULL();
/* Convert to text */
PG_RETURN_TEXT_P(cstring_to_text(varval));

2
src/include/catalog/catversion.h
View File

@ -53,6 +53,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 201506282
#define CATALOG_VERSION_NO 201507021
#endif

6
src/include/catalog/pg_proc.h
View File

@ -3067,6 +3067,8 @@ DESCR("convert bitstring to int8");
DATA(insert OID = 2077 ( current_setting PGNSP PGUID 12 1 0 0 0 f f f f t f s 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ show_config_by_name _null_ _null_ _null_ ));
DESCR("SHOW X as a function");
DATA(insert OID = 3294 ( current_setting PGNSP PGUID 12 1 0 0 0 f f f f t f s 2 0 25 "25 16" _null_ _null_ _null_ _null_ _null_ show_config_by_name_missing_ok _null_ _null_ _null_ ));
DESCR("SHOW X as a function, optionally no error for missing variable");
DATA(insert OID = 2078 ( set_config PGNSP PGUID 12 1 0 0 0 f f f f f f v 3 0 25 "25 25 16" _null_ _null_ _null_ _null_ _null_ set_config_by_name _null_ _null_ _null_ ));
DESCR("SET X as a function");
DATA(insert OID = 2084 ( pg_show_all_settings PGNSP PGUID 12 1 1000 0 0 f f f f t t s 0 0 2249 "" "{25,25,25,25,25,25,25,25,25,25,25,1009,25,25,25,23,16}" "{o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}" "{name,setting,unit,category,short_desc,extra_desc,context,vartype,source,min_val,max_val,enumvals,boot_val,reset_val,sourcefile,sourceline,pending_restart}" _null_ _null_ show_all_settings _null_ _null_ _null_ ));
@ -4866,8 +4868,8 @@ DESCR("GIN support");
DATA(insert OID = 3301 ( jsonb_concat PGNSP PGUID 12 1 0 0 0 f f f f t f i 2 0 3802 "3802 3802" _null_ _null_ _null_ _null_ _null_ jsonb_concat _null_ _null_ _null_ ));
DATA(insert OID = 3302 ( jsonb_delete PGNSP PGUID 12 1 0 0 0 f f f f t f i 2 0 3802 "3802 25" _null_ _null_ _null_ _null_ _null_ jsonb_delete _null_ _null_ _null_ ));
DATA(insert OID = 3303 ( jsonb_delete PGNSP PGUID 12 1 0 0 0 f f f f t f i 2 0 3802 "3802 23" _null_ _null_ _null_ _null_ _null_ jsonb_delete_idx _null_ _null_ _null_ ));
DATA(insert OID = 3304 ( jsonb_delete_path PGNSP PGUID 12 1 0 0 0 f f f f t f i 2 0 3802 "3802 1009" _null_ _null_ _null_ _null_ _null_ jsonb_delete_path _null_ _null_ _null_ ));
DATA(insert OID = 3305 ( jsonb_set PGNSP PGUID 12 1 0 0 0 f f f f t f i 4 0 3802 "3802 1009 3802 16" _null_ _null_ _null_ _null_ _null_ jsonb_set _null_ _null_ _null_ ));
DATA(insert OID = 3304 ( jsonb_delete_path PGNSP PGUID 12 1 0 0 0 f f f f t f i 2 0 3802 "3802 1009" _null_ _null_ _null_ _null_ _null_ jsonb_delete_path _null_ _null_ _null_ ));
DATA(insert OID = 3305 ( jsonb_set PGNSP PGUID 12 1 0 0 0 f f f f t f i 4 0 3802 "3802 1009 3802 16" _null_ _null_ _null_ _null_ _null_ jsonb_set _null_ _null_ _null_ ));
DESCR("Set part of a jsonb");
DATA(insert OID = 3306 ( jsonb_pretty PGNSP PGUID 12 1 0 0 0 f f f f t f i 1 0 25 "3802" _null_ _null_ _null_ _null_ _null_ jsonb_pretty _null_ _null_ _null_ ));
DESCR("Indented text from jsonb");

1
src/include/utils/builtins.h
View File

@ -1114,6 +1114,7 @@ extern Datum quote_nullable(PG_FUNCTION_ARGS);
/* guc.c */
extern Datum show_config_by_name(PG_FUNCTION_ARGS);
extern Datum show_config_by_name_missing_ok(PG_FUNCTION_ARGS);
extern Datum set_config_by_name(PG_FUNCTION_ARGS);
extern Datum show_all_settings(PG_FUNCTION_ARGS);
extern Datum show_all_file_settings(PG_FUNCTION_ARGS);

3
src/include/utils/guc.h
View File

@ -365,7 +365,8 @@ extern int set_config_option(const char *name, const char *value,
GucAction action, bool changeVal, int elevel,
bool is_reload);
extern void AlterSystemSetConfigFile(AlterSystemStmt *setstmt);
extern char *GetConfigOptionByName(const char *name, const char **varname);
extern char *GetConfigOptionByName(const char *name, const char **varname,
bool missing_ok);
extern void GetConfigOptionByNum(int varnum, const char **values, bool *noshow);
extern int GetNumConfigOptions(void);

31
src/test/regress/expected/guc.out
View File

@ -720,6 +720,37 @@ select myfunc(1), current_setting('work_mem');
2MB | 2MB
(1 row)
-- check current_setting()'s behavior with invalid setting name
select current_setting('nosuch.setting'); -- FAIL
ERROR: unrecognized configuration parameter "nosuch.setting"
select current_setting('nosuch.setting', false); -- FAIL
ERROR: unrecognized configuration parameter "nosuch.setting"
select current_setting('nosuch.setting', true) is null;
?column?
----------
t
(1 row)
-- after this, all three cases should yield 'nada'
set nosuch.setting = 'nada';
select current_setting('nosuch.setting');
current_setting
-----------------
nada
(1 row)
select current_setting('nosuch.setting', false);
current_setting
-----------------
nada
(1 row)
select current_setting('nosuch.setting', true);
current_setting
-----------------
nada
(1 row)
-- Normally, CREATE FUNCTION should complain about invalid values in
-- function SET options; but not if check_function_bodies is off,
-- because that creates ordering hazards for pg_dump

13
src/test/regress/sql/guc.sql
View File

@ -258,6 +258,19 @@ select myfunc(0);
select current_setting('work_mem');
select myfunc(1), current_setting('work_mem');
-- check current_setting()'s behavior with invalid setting name
select current_setting('nosuch.setting'); -- FAIL
select current_setting('nosuch.setting', false); -- FAIL
select current_setting('nosuch.setting', true) is null;
-- after this, all three cases should yield 'nada'
set nosuch.setting = 'nada';
select current_setting('nosuch.setting');
select current_setting('nosuch.setting', false);
select current_setting('nosuch.setting', true);
-- Normally, CREATE FUNCTION should complain about invalid values in
-- function SET options; but not if check_function_bodies is off,
-- because that creates ordering hazards for pg_dump