Re: Partition-wise join for join between (declaratively) partitioned tables

Amit Langote <langote_amit_f8@lab.ntt.co.jp>

From: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>

To: Robert Haas <robertmhaas@gmail.com>, Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>

Cc: Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com>, pgsql-hackers <pgsql-hackers@postgresql.org>

Date: 2017-03-14T00:58:28Z

Lists: pgsql-hackers

On 2017/03/14 9:17, Robert Haas wrote:
> On Mon, Mar 13, 2017 at 3:24 PM, Robert Haas <robertmhaas@gmail.com> wrote:
>> Haven't looked at 0007 yet.
> 
> Overall this one looks pretty good and straightforward.

In the following code of find_partition_scheme():

+	/* Did not find matching partition scheme. Create one. */
+	part_scheme = (PartitionScheme) palloc0(sizeof(PartitionSchemeData));
+
+	/* Copy partition bounds/lists. */
+	part_scheme->nparts = part_desc->nparts;
+	part_scheme->strategy = part_key->strategy;
+	part_scheme->boundinfo = part_desc->boundinfo;
+
+	/* Store partition key information. */
+	part_scheme->partnatts = part_key->partnatts;
+
+	part_scheme->partopfamily = (Oid *) palloc(sizeof(Oid) * partnatts);
+	memcpy(part_scheme->partopfamily, part_key->partopfamily,
+		   sizeof(Oid) * partnatts);
+
+	part_scheme->partopcintype = (Oid *) palloc(sizeof(Oid) * partnatts);
+	memcpy(part_scheme->partopcintype, part_key->partopcintype,
+		   sizeof(Oid) * partnatts);
+
+	part_scheme->key_types = (Oid *) palloc(sizeof(Oid) * partnatts);
+	memcpy(part_scheme->key_types, part_key->parttypid,
+		   sizeof(Oid) * partnatts);
+
+	part_scheme->key_typmods = (int32 *) palloc(sizeof(int32) * partnatts);
+	memcpy(part_scheme->key_typmods, part_key->parttypmod,
+		   sizeof(int32) * partnatts);
+
+	part_scheme->key_collations = (Oid *) palloc(sizeof(Oid) * partnatts);
+	memcpy(part_scheme->key_collations, part_key->parttypcoll,
+		   sizeof(Oid) * partnatts);

Couldn't we avoid the memcpy() on individual members of part_key?  After
all, RelationData.rd_partkey is guarded just like rd_partdesc by
relcache.c in face of invalidations (see keep_partkey logic in
RelationClearRelation).

Thanks,
Amit

Commits

Basic partition-wise join functionality.
- f49842d1ee31 11.0 landed
Assorted preparatory refactoring for partition-wise join.
- e139f1953f29 11.0 landed
Teach adjust_appendrel_attrs(_multilevel) to do multiple translations.
- 480f1f4329f1 11.0 landed
Stamp 10beta2.
- 42171e2cd23c 10.0 cited
Eat XIDs more efficiently in recovery TAP test.
- 08aed6604de2 10.0 cited
Abstract logic to allow for multiple kinds of child rels.
- 7a39b5e4d112 10.0 landed
Implement SortSupport for macaddr data type
- f90d23d0c518 10.0 cited
Attempt to stabilize grouping sets regression test plans.
- de4da168d57d 10.0 cited
Teach xlogreader to follow timeline switches
- 1148e22a82ed 10.0 cited
Don't scan partitioned tables.
- d3cc37f1d801 10.0 cited
Fix grammar.
- b4ff8609dbad 10.0 cited
postgres_fdw: Push down FULL JOINs with restriction clauses.
- b30fb56b07a8 10.0 cited
Some preliminary refactoring towards partitionwise join.
- c44c47a773bd 10.0 landed
contrib/amcheck needs RecentGlobalXmin to be PGDLLIMPORT'ified.
- 56018bf26eec 10.0 cited
Print test parameters like "foo: 123", and results like "foo = 123".
- 2a7f4f76434d 10.0 cited