their partitions, and so on.
</entry>
</row>
+ <row>
+ <entry>
+ <indexterm><primary>pg_partition_root</primary></indexterm>
+ <literal><function>pg_partition_root(<type>regclass</type>)</function></literal>
+ </entry>
+ <entry><type>regclass</type></entry>
+ <entry>
+ Return the top-most parent of a partition tree to which the given
+ relation belongs.
+ </entry>
+ </row>
</tbody>
</tgroup>
</table>
#include "utils/lsyscache.h"
#include "utils/syscache.h"
+/*
+ * Checks if a given relation can be part of a partition tree. Returns
+ * false if the relation cannot be processed, in which case it is up to
+ * the caller to decide what to do, by either raising an error or doing
+ * something else.
+ */
+static bool
+check_rel_can_be_partition(Oid relid)
+{
+ char relkind;
+
+ /* Check if relation exists */
+ if (!SearchSysCacheExists1(RELOID, ObjectIdGetDatum(relid)))
+ return false;
+
+ relkind = get_rel_relkind(relid);
+
+ /* Only allow relation types that can appear in partition trees. */
+ if (relkind != RELKIND_RELATION &&
+ relkind != RELKIND_FOREIGN_TABLE &&
+ relkind != RELKIND_INDEX &&
+ relkind != RELKIND_PARTITIONED_TABLE &&
+ relkind != RELKIND_PARTITIONED_INDEX)
+ return false;
+
+ return true;
+}
/*
* pg_partition_tree
{
#define PG_PARTITION_TREE_COLS 4
Oid rootrelid = PG_GETARG_OID(0);
- char relkind = get_rel_relkind(rootrelid);
FuncCallContext *funcctx;
ListCell **next;
- if (!SearchSysCacheExists1(RELOID, ObjectIdGetDatum(rootrelid)))
- PG_RETURN_NULL();
-
- /* Return NULL for relation types that cannot appear in partition trees */
- if (relkind != RELKIND_RELATION &&
- relkind != RELKIND_FOREIGN_TABLE &&
- relkind != RELKIND_INDEX &&
- relkind != RELKIND_PARTITIONED_TABLE &&
- relkind != RELKIND_PARTITIONED_INDEX)
+ if (!check_rel_can_be_partition(rootrelid))
PG_RETURN_NULL();
/* stuff done only on the first call of the function */
/* done when there are no more elements left */
SRF_RETURN_DONE(funcctx);
}
+
+/*
+ * pg_partition_root
+ *
+ * Returns the top-most parent of the partition tree to which a given
+ * relation belongs, or NULL if it's not (or cannot be) part of any
+ * partition tree.
+ */
+Datum
+pg_partition_root(PG_FUNCTION_ARGS)
+{
+ Oid relid = PG_GETARG_OID(0);
+ Oid rootrelid;
+ List *ancestors;
+
+ if (!check_rel_can_be_partition(relid))
+ PG_RETURN_NULL();
+
+ /*
+ * If the relation is not a partition (it may be the partition parent),
+ * return itself as a result.
+ */
+ if (!get_rel_relispartition(relid))
+ PG_RETURN_OID(relid);
+
+ /* Fetch the top-most parent */
+ ancestors = get_partition_ancestors(relid);
+ rootrelid = llast_oid(ancestors);
+ list_free(ancestors);
+
+ /*
+ * "rootrelid" must contain a valid OID, given that the input relation is
+ * a valid partition tree member as checked above.
+ */
+ Assert(OidIsValid(rootrelid));
+ PG_RETURN_OID(rootrelid);
+}
*/
/* yyyymmddN */
-#define CATALOG_VERSION_NO 201902071
+#define CATALOG_VERSION_NO 201902081
#endif
proargnames => '{rootrelid,relid,parentrelid,isleaf,level}',
prosrc => 'pg_partition_tree' },
+# function to get the top-most partition root parent
+{ oid => '3424', descr => 'get top-most partition root parent',
+ proname => 'pg_partition_root', prorettype => 'regclass',
+ proargtypes => 'regclass', prosrc => 'pg_partition_root' },
+
]
| | |
(1 row)
+SELECT pg_partition_root(NULL);
+ pg_partition_root
+-------------------
+
+(1 row)
+
+SELECT pg_partition_root(0);
+ pg_partition_root
+-------------------
+
+(1 row)
+
-- Test table partition trees
CREATE TABLE ptif_test (a int, b int) PARTITION BY range (a);
CREATE TABLE ptif_test0 PARTITION OF ptif_test
ptif_test01 | ptif_test0 | 0 | t
(1 row)
+-- List all members using pg_partition_root with leaf table reference
+SELECT relid, parentrelid, level, isleaf
+ FROM pg_partition_tree(pg_partition_root('ptif_test01')) p
+ JOIN pg_class c ON (p.relid = c.oid);
+ relid | parentrelid | level | isleaf
+-------------+-------------+-------+--------
+ ptif_test | | 0 | f
+ ptif_test0 | ptif_test | 1 | f
+ ptif_test1 | ptif_test | 1 | f
+ ptif_test2 | ptif_test | 1 | t
+ ptif_test01 | ptif_test0 | 2 | t
+ ptif_test11 | ptif_test1 | 2 | t
+(6 rows)
+
-- List all indexes members of the tree
SELECT relid, parentrelid, level, isleaf
FROM pg_partition_tree('ptif_test_index');
ptif_test01_index | ptif_test0_index | 0 | t
(1 row)
+-- List all members using pg_partition_root with leaf index reference
+SELECT relid, parentrelid, level, isleaf
+ FROM pg_partition_tree(pg_partition_root('ptif_test01_index')) p
+ JOIN pg_class c ON (p.relid = c.oid);
+ relid | parentrelid | level | isleaf
+-------------------+------------------+-------+--------
+ ptif_test_index | | 0 | f
+ ptif_test0_index | ptif_test_index | 1 | f
+ ptif_test1_index | ptif_test_index | 1 | f
+ ptif_test2_index | ptif_test_index | 1 | t
+ ptif_test01_index | ptif_test0_index | 2 | t
+ ptif_test11_index | ptif_test1_index | 2 | t
+(6 rows)
+
DROP TABLE ptif_test;
-- Table that is not part of any partition tree is the only member listed.
CREATE TABLE ptif_normal_table(a int);
ptif_normal_table | | 0 | t
(1 row)
+SELECT pg_partition_root('ptif_normal_table');
+ pg_partition_root
+-------------------
+ ptif_normal_table
+(1 row)
+
DROP TABLE ptif_normal_table;
-- Various partitioning-related functions return NULL if passed relations
-- of types that cannot be part of a partition tree; for example, views,
| | |
(1 row)
+SELECT pg_partition_root('ptif_test_view');
+ pg_partition_root
+-------------------
+
+(1 row)
+
+SELECT pg_partition_root('ptif_test_matview');
+ pg_partition_root
+-------------------
+
+(1 row)
+
DROP VIEW ptif_test_view;
DROP MATERIALIZED VIEW ptif_test_matview;
--
SELECT * FROM pg_partition_tree(NULL);
SELECT * FROM pg_partition_tree(0);
+SELECT pg_partition_root(NULL);
+SELECT pg_partition_root(0);
-- Test table partition trees
CREATE TABLE ptif_test (a int, b int) PARTITION BY range (a);
SELECT relid, parentrelid, level, isleaf
FROM pg_partition_tree('ptif_test01') p
JOIN pg_class c ON (p.relid = c.oid);
+-- List all members using pg_partition_root with leaf table reference
+SELECT relid, parentrelid, level, isleaf
+ FROM pg_partition_tree(pg_partition_root('ptif_test01')) p
+ JOIN pg_class c ON (p.relid = c.oid);
-- List all indexes members of the tree
SELECT relid, parentrelid, level, isleaf
SELECT relid, parentrelid, level, isleaf
FROM pg_partition_tree('ptif_test01_index') p
JOIN pg_class c ON (p.relid = c.oid);
+-- List all members using pg_partition_root with leaf index reference
+SELECT relid, parentrelid, level, isleaf
+ FROM pg_partition_tree(pg_partition_root('ptif_test01_index')) p
+ JOIN pg_class c ON (p.relid = c.oid);
DROP TABLE ptif_test;
CREATE TABLE ptif_normal_table(a int);
SELECT relid, parentrelid, level, isleaf
FROM pg_partition_tree('ptif_normal_table');
+SELECT pg_partition_root('ptif_normal_table');
DROP TABLE ptif_normal_table;
-- Various partitioning-related functions return NULL if passed relations
CREATE MATERIALIZED VIEW ptif_test_matview AS SELECT 1;
SELECT * FROM pg_partition_tree('ptif_test_view');
SELECT * FROM pg_partition_tree('ptif_test_matview');
+SELECT pg_partition_root('ptif_test_view');
+SELECT pg_partition_root('ptif_test_matview');
DROP VIEW ptif_test_view;
DROP MATERIALIZED VIEW ptif_test_matview;
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