Re: [HACKERS] Partition-wise join for join between (declaratively)partitioned tables - Mailing list 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