pg_get_partkeydef: return NULL for non-partitions

Our general rule for pg_get_X(oid) functions is to simply return NULL
when passed an invalid or inappropriate OID.  Teach pg_get_partkeydef to
do this also, making it easier for users to use this function when
querying against tables with both partitions and non-partitions (such as
pg_class).

As a concrete example, this makes pg_dump's life a little easier.

Author: Amit Langote
This commit is contained in:
Stephen Frost 2017-04-26 14:59:22 -04:00
parent 49da00677d
commit 0c76c2463e
3 changed files with 21 additions and 6 deletions

View File

@ -320,7 +320,7 @@ static char *pg_get_indexdef_worker(Oid indexrelid, int colno,
int prettyFlags, bool missing_ok);
static char *pg_get_statisticsext_worker(Oid statextid, bool missing_ok);
static char *pg_get_partkeydef_worker(Oid relid, int prettyFlags,
bool attrsOnly);
bool attrsOnly, bool missing_ok);
static char *pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
int prettyFlags, bool missing_ok);
static text *pg_get_expr_worker(text *expr, Oid relid, const char *relname,
@ -1555,10 +1555,14 @@ Datum
pg_get_partkeydef(PG_FUNCTION_ARGS)
{
Oid relid = PG_GETARG_OID(0);
char *res;
PG_RETURN_TEXT_P(string_to_text(pg_get_partkeydef_worker(relid,
PRETTYFLAG_INDENT,
false)));
res = pg_get_partkeydef_worker(relid, PRETTYFLAG_INDENT, false, true);
if (res == NULL)
PG_RETURN_NULL();
PG_RETURN_TEXT_P(string_to_text(res));
}
/* Internal version that just reports the column definitions */
@ -1568,7 +1572,7 @@ pg_get_partkeydef_columns(Oid relid, bool pretty)
int prettyFlags;
prettyFlags = pretty ? PRETTYFLAG_PAREN | PRETTYFLAG_INDENT : PRETTYFLAG_INDENT;
return pg_get_partkeydef_worker(relid, prettyFlags, true);
return pg_get_partkeydef_worker(relid, prettyFlags, true, false);
}
/*
@ -1576,7 +1580,7 @@ pg_get_partkeydef_columns(Oid relid, bool pretty)
*/
static char *
pg_get_partkeydef_worker(Oid relid, int prettyFlags,
bool attrsOnly)
bool attrsOnly, bool missing_ok)
{
Form_pg_partitioned_table form;
HeapTuple tuple;
@ -1594,7 +1598,11 @@ pg_get_partkeydef_worker(Oid relid, int prettyFlags,
tuple = SearchSysCache1(PARTRELID, ObjectIdGetDatum(relid));
if (!HeapTupleIsValid(tuple))
{
if (missing_ok)
return NULL;
elog(ERROR, "cache lookup failed for partition key of %u", relid);
}
form = (Form_pg_partitioned_table) GETSTRUCT(tuple);

View File

@ -3212,6 +3212,12 @@ SELECT pg_get_function_arg_default('pg_class'::regclass, 0);
(1 row)
SELECT pg_get_partkeydef(0);
pg_get_partkeydef
-------------------
(1 row)
-- test rename for a rule defined on a partitioned table
CREATE TABLE parted_table (a int) PARTITION BY LIST (a);
CREATE TABLE parted_table_1 PARTITION OF parted_table FOR VALUES IN (1);

View File

@ -1163,6 +1163,7 @@ SELECT pg_get_function_identity_arguments(0);
SELECT pg_get_function_result(0);
SELECT pg_get_function_arg_default(0, 0);
SELECT pg_get_function_arg_default('pg_class'::regclass, 0);
SELECT pg_get_partkeydef(0);
-- test rename for a rule defined on a partitioned table
CREATE TABLE parted_table (a int) PARTITION BY LIST (a);