On 2018/08/01 22:21, Robert Haas wrote:
> On Thu, Jul 26, 2018 at 4:47 AM, Amit Langote
> <[email protected]> wrote:
>> Alright, I have replaced pg_partition_tree_tables with
>> pg_partition_children with an 'include_all' argument, as you suggested,
>> but I implemented it as an optional argument. So, one would use that
>> argument only if need to get *all* partitions. I have also added a
>> pg_partition_leaf_children() that returns just the leaf partitions, which
>> wasn't there in the previous versions.
>>
>> Further, I've added a pg_partition_level that returns the level of a
>> partition in the partition tree wrt to the root of the *whole* partition
>> tree. But maybe we want this function to accept one more argument,
>> 'rootoid', the OID of the root table against which to measure the level?
>
> I have another idea. Suppose we just have one function, and that
> function a set of records, and each record contains (1) the OID of a
> table, (2) the OID of the immediate parent or NULL for the root, and
> (3) the level (0 = root, 1 = child, 2 = grandchild, etc.).
>
> So then to get the immediate children you would say:
>
> SELECT * FROM pg_whatever() WHERE level = 1
>
> And to get everything you would just say:
>
> SELECT * FROM pg_whatever();
>
> And if you wanted grandchildren or everything but the root or whatever
> you could just adjust the WHERE clause.
>
> By including the OID of the immediate parent, there's enough
> information for application code to draw an actual graph if it wants,
> which doesn't work so well if you just know the levels.
That's a good idea, thanks.
Actually, by the time I sent the last version of the patch or maybe few
versions before that, I too had started thinking if we shouldn't just have
a SETOF RECORD function like you've outlined here, but wasn't sure of the
fields it should have. (relid, parentid, level) seems like a good start,
or maybe that's just what we need.
I tried to implement such a function. Example usage:
create table q (a int, b int, c int) partition by list (a);
create table q1 partition of q for values in (1) partition by hash (b);
create table q11 partition of q1 for values with (modulus 1, remainder 0)
partition by hash (c);
create table q111 partition of q11 for values with (modulus 1, remainder 0);
create table q2 partition of q for values in (2);
insert into q select i%2+1, i, i from generate_series(1, 1000) i;
select * from pg_partition_children('q');
relid │ parentid │ level
───────┼──────────┼───────
q │ │ 0
q1 │ q │ 1
q2 │ q │ 1
q11 │ q1 │ 2
q111 │ q11 │ 3
(5 rows)
select * from pg_partition_children('q') where level > 0;
relid │ parentid │ level
───────┼──────────┼───────
q1 │ q │ 1
q2 │ q │ 1
q11 │ q1 │ 2
q111 │ q11 │ 3
(4 rows)
select * from pg_partition_children('q') where level = 1;
relid │ parentid │ level
───────┼──────────┼───────
q1 │ q │ 1
q2 │ q │ 1
(2 rows)
select *, pg_relation_size(relid) as size from pg_partition_children('q');
relid │ parentid │ level │ size
───────┼──────────┼───────┼───────
q │ │ 0 │ 0
q1 │ q │ 1 │ 0
q2 │ q │ 1 │ 24576
q11 │ q1 │ 2 │ 0
q111 │ q11 │ 3 │ 24576
(5 rows)
select sum(pg_relation_size(relid)) as size from pg_partition_children('q');
size
───────
49152
(1 row)
select *, pg_relation_size(relid) as size from pg_partition_children('q1');
relid │ parentid │ level │ size
───────┼──────────┼───────┼───────
q1 │ q │ 0 │ 0
q11 │ q1 │ 1 │ 0
q111 │ q11 │ 2 │ 24576
(3 rows)
select *, pg_relation_size(relid) as size from pg_partition_children('q11');
relid │ parentid │ level │ size
───────┼──────────┼───────┼───────
q11 │ q1 │ 0 │ 0
q111 │ q11 │ 1 │ 24576
(2 rows)
select *, pg_relation_size(relid) as size from pg_partition_children('q111');
relid │ parentid │ level │ size
───────┼──────────┼───────┼───────
q111 │ q11 │ 0 │ 24576
(1 row)
Note that the level that's returned for each table is computed wrt the
root table passed to the function and not the actual root partition.
I have updated the patch to include just this one function, its
documentation, and tests.
Regards,
Amit
From 5dee35a24ea96b8bc62578f533dec00dcdc56476 Mon Sep 17 00:00:00 2001
From: amit <[email protected]>
Date: Fri, 3 Aug 2018 17:06:05 +0900
Subject: [PATCH v9] Add pg_partition_children to report partitions
It returns set of records one for each partition containing the
partition name, parent name, and level in the partition tree with
given table as root
---
doc/src/sgml/func.sgml | 33 +++++++++++
src/backend/catalog/partition.c | 83 ++++++++++++++++++++++++++++
src/include/catalog/pg_proc.dat | 7 +++
src/test/regress/expected/partition_info.out | 75 +++++++++++++++++++++++++
src/test/regress/parallel_schedule | 2 +-
src/test/regress/serial_schedule | 1 +
src/test/regress/sql/partition_info.sql | 32 +++++++++++
7 files changed, 232 insertions(+), 1 deletion(-)
create mode 100644 src/test/regress/expected/partition_info.out
create mode 100644 src/test/regress/sql/partition_info.sql
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index edc9be92a6..a6e52837ac 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -19995,6 +19995,39 @@ postgres=# SELECT * FROM
pg_walfile_name_offset(pg_stop_backup());
The function returns the number of new collation objects it created.
</para>
+ <table id="functions-info-partition">
+ <title>Partitioning Information Functions</title>
+ <tgroup cols="3">
+ <thead>
+ <row><entry>Name</entry> <entry>Return Type</entry>
<entry>Description</entry></row>
+ </thead>
+
+ <tbody>
+ <row>
+
<entry><literal><function>pg_partition_children(<type>regclass</type>)</function></literal></entry>
+ <entry><type>setof record</type></entry>
+ <entry>List name, parent name, and level of each partition contained in
the partition tree with given root table, including the root table
itself</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ To check the total size of the data contained in
+ <structname>measurement</structname> table described in
+ <xref linkend="ddl-partitioning-declarative-example"/>, one could use the
+ following query:
+ </para>
+
+<programlisting>
+select pg_size_pretty(sum(pg_relation_size(relid))) as total_size from
pg_partition_children('measurement');
+ total_size
+------------
+ 24 kB
+(1 row)
+</programlisting>
+
+
</sect2>
<sect2 id="functions-admin-index">
diff --git a/src/backend/catalog/partition.c b/src/backend/catalog/partition.c
index 558022647c..98a9fb3fd8 100644
--- a/src/backend/catalog/partition.c
+++ b/src/backend/catalog/partition.c
@@ -23,12 +23,15 @@
#include "catalog/partition.h"
#include "catalog/pg_inherits.h"
#include "catalog/pg_partitioned_table.h"
+#include "catalog/pg_type.h"
+#include "funcapi.h"
#include "nodes/makefuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/prep.h"
#include "optimizer/var.h"
#include "partitioning/partbounds.h"
#include "rewrite/rewriteManip.h"
+#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/partcache.h"
#include "utils/rel.h"
@@ -357,3 +360,83 @@ get_proposed_default_constraint(List *new_part_constraints)
return make_ands_implicit(defPartConstraint);
}
+
+Datum
+pg_partition_children(PG_FUNCTION_ARGS)
+{
+ Oid rootrelid = PG_GETARG_OID(0);
+ FuncCallContext *funccxt;
+ ListCell **next;
+
+ if (SRF_IS_FIRSTCALL())
+ {
+ MemoryContext oldcxt;
+ TupleDesc tupdesc;
+ List *partitions;
+
+ funccxt = SRF_FIRSTCALL_INIT();
+ oldcxt = MemoryContextSwitchTo(funccxt->multi_call_memory_ctx);
+
+ partitions = find_all_inheritors(rootrelid, NoLock, NULL);
+
+ tupdesc = CreateTemplateTupleDesc(3, false);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 1, "relid",
+ REGCLASSOID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 2, "parentid",
+ REGCLASSOID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 3, "level",
+ INT4OID, -1, 0);
+
+ next = (ListCell **) palloc(sizeof(ListCell *));
+ *next = list_head(partitions);
+
+ funccxt->attinmeta = TupleDescGetAttInMetadata(tupdesc);
+ funccxt->user_fctx = (void *) next;
+
+ MemoryContextSwitchTo(oldcxt);
+ }
+
+ funccxt = SRF_PERCALL_SETUP();
+ next = (ListCell **) funccxt->user_fctx;
+
+ if (*next != NULL)
+ {
+ HeapTuple tuple;
+ char *values[3];
+ Oid relid = lfirst_oid(*next);
+ List *ancestors =
get_partition_ancestors(lfirst_oid(*next));
+ Oid parent = InvalidOid;
+ int level = 0;
+ ListCell *lc;
+
+ /* relid */
+ values[0] = psprintf("%u", relid);
+
+ /* parentid */
+ if (ancestors != NIL)
+ parent = linitial_oid(ancestors);
+ if (OidIsValid(parent))
+ values[1] = psprintf("%u", parent);
+ else
+ values[1] = NULL;
+
+ /* level */
+ if (relid != rootrelid)
+ {
+ foreach(lc, ancestors)
+ {
+ level++;
+ if (lfirst_oid(lc) == rootrelid)
+ break;
+ }
+ }
+ values[2] = psprintf("%u", level);
+
+ tuple = BuildTupleFromCStrings(funccxt->attinmeta, values);
+
+ *next = lnext(*next);
+ SRF_RETURN_NEXT(funccxt, HeapTupleGetDatum(tuple));
+ }
+
+ SRF_RETURN_DONE(funccxt);
+}
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index a14651010f..c1df79508e 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -10206,4 +10206,11 @@
proisstrict => 'f', prorettype => 'bool', proargtypes => 'oid int4 int4 any',
proargmodes => '{i,i,i,v}', prosrc => 'satisfies_hash_partition' },
+# function to get tables in partition tree of a given root table
+{ oid => '3423', descr => 'view partition tree tables',
+ proname => 'pg_partition_children', prorows => '1000', proretset => 't',
+ provolatile => 'v', prorettype => 'record', proargtypes => 'regclass',
+ proallargtypes => '{regclass,regclass,regclass,int4}', proargmodes =>
'{i,o,o,o}',
+ proargnames => '{rootrelid,relid,parentid,level}', prosrc =>
'pg_partition_children' }
+
]
diff --git a/src/test/regress/expected/partition_info.out
b/src/test/regress/expected/partition_info.out
new file mode 100644
index 0000000000..4908cbc796
--- /dev/null
+++ b/src/test/regress/expected/partition_info.out
@@ -0,0 +1,75 @@
+--
+-- Tests for pg_partition_children
+--
+create table ptif_test (a int, b int) partition by range (a);
+create table ptif_test0 partition of ptif_test for values from (minvalue) to
(0) partition by list (b);
+create table ptif_test01 partition of ptif_test0 for values in (1);
+create table ptif_test1 partition of ptif_test for values from (0) to (100)
partition by list (b);
+create table ptif_test11 partition of ptif_test1 for values in (1);
+create table ptif_test2 partition of ptif_test for values from (100) to
(maxvalue);
+insert into ptif_test select i, 1 from generate_series(-500, 500) i;
+-- all tables in the tree
+select *, pg_relation_size(relid) as size from
pg_partition_children('ptif_test');
+ relid | parentid | level | size
+-------------+------------+-------+-------
+ ptif_test | | 0 | 0
+ ptif_test0 | ptif_test | 1 | 0
+ ptif_test1 | ptif_test | 1 | 0
+ ptif_test2 | ptif_test | 1 | 16384
+ ptif_test01 | ptif_test0 | 2 | 24576
+ ptif_test11 | ptif_test1 | 2 | 8192
+(6 rows)
+
+-- all table excluding the root
+select *, pg_relation_size(relid) as size from
pg_partition_children('ptif_test') where level > 0;
+ relid | parentid | level | size
+-------------+------------+-------+-------
+ ptif_test0 | ptif_test | 1 | 0
+ ptif_test1 | ptif_test | 1 | 0
+ ptif_test2 | ptif_test | 1 | 16384
+ ptif_test01 | ptif_test0 | 2 | 24576
+ ptif_test11 | ptif_test1 | 2 | 8192
+(5 rows)
+
+-- total size of all partitions
+select sum(pg_relation_size(relid)) as total_size from
pg_partition_children('ptif_test');
+ total_size
+------------
+ 49152
+(1 row)
+
+-- total size of first level partitions
+select sum(pg_relation_size(relid)) as total_size from
pg_partition_children('ptif_test') where level = 1;
+ total_size
+------------
+ 16384
+(1 row)
+
+-- check that passing a lower-level table to pg_partition_children works
+select *, pg_relation_size(relid) as size from
pg_partition_children('ptif_test0');
+ relid | parentid | level | size
+-------------+------------+-------+-------
+ ptif_test0 | ptif_test | 0 | 0
+ ptif_test01 | ptif_test0 | 1 | 24576
+(2 rows)
+
+select *, pg_relation_size(relid) as size from
pg_partition_children('ptif_test01');
+ relid | parentid | level | size
+-------------+------------+-------+-------
+ ptif_test01 | ptif_test0 | 0 | 24576
+(1 row)
+
+select sum(pg_relation_size(relid)) as total_size from
pg_partition_children('ptif_test01');
+ total_size
+------------
+ 24576
+(1 row)
+
+-- this one should result in null, as there are no level 1 partitions of a
leaf partition
+select sum(pg_relation_size(relid)) as total_size from
pg_partition_children('ptif_test01') where level = 1;
+ total_size
+------------
+
+(1 row)
+
+drop table ptif_test;
diff --git a/src/test/regress/parallel_schedule
b/src/test/regress/parallel_schedule
index 16f979c8d9..6cb820bbc4 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -116,7 +116,7 @@ test: plancache limit plpgsql copy2 temp domain rangefuncs
prepare without_oid c
# ----------
# Another group of parallel tests
# ----------
-test: identity partition_join partition_prune reloptions hash_part indexing
partition_aggregate
+test: identity partition_join partition_prune reloptions hash_part indexing
partition_aggregate partition_info
# event triggers cannot run concurrently with any test that runs DDL
test: event_trigger
diff --git a/src/test/regress/serial_schedule b/src/test/regress/serial_schedule
index 42632be675..7e374c2daa 100644
--- a/src/test/regress/serial_schedule
+++ b/src/test/regress/serial_schedule
@@ -188,6 +188,7 @@ test: reloptions
test: hash_part
test: indexing
test: partition_aggregate
+test: partition_info
test: event_trigger
test: fast_default
test: stats
diff --git a/src/test/regress/sql/partition_info.sql
b/src/test/regress/sql/partition_info.sql
new file mode 100644
index 0000000000..481d165be0
--- /dev/null
+++ b/src/test/regress/sql/partition_info.sql
@@ -0,0 +1,32 @@
+--
+-- Tests for pg_partition_children
+--
+create table ptif_test (a int, b int) partition by range (a);
+create table ptif_test0 partition of ptif_test for values from (minvalue) to
(0) partition by list (b);
+create table ptif_test01 partition of ptif_test0 for values in (1);
+create table ptif_test1 partition of ptif_test for values from (0) to (100)
partition by list (b);
+create table ptif_test11 partition of ptif_test1 for values in (1);
+create table ptif_test2 partition of ptif_test for values from (100) to
(maxvalue);
+insert into ptif_test select i, 1 from generate_series(-500, 500) i;
+
+-- all tables in the tree
+select *, pg_relation_size(relid) as size from
pg_partition_children('ptif_test');
+
+-- all table excluding the root
+select *, pg_relation_size(relid) as size from
pg_partition_children('ptif_test') where level > 0;
+
+-- total size of all partitions
+select sum(pg_relation_size(relid)) as total_size from
pg_partition_children('ptif_test');
+
+-- total size of first level partitions
+select sum(pg_relation_size(relid)) as total_size from
pg_partition_children('ptif_test') where level = 1;
+
+-- check that passing a lower-level table to pg_partition_children works
+select *, pg_relation_size(relid) as size from
pg_partition_children('ptif_test0');
+select *, pg_relation_size(relid) as size from
pg_partition_children('ptif_test01');
+select sum(pg_relation_size(relid)) as total_size from
pg_partition_children('ptif_test01');
+
+-- this one should result in null, as there are no level 1 partitions of a
leaf partition
+select sum(pg_relation_size(relid)) as total_size from
pg_partition_children('ptif_test01') where level = 1;
+
+drop table ptif_test;
--
2.11.0
