On 4 October 2018 at 16:22, Harry B <harrysun...@gmail.com> wrote: > I am still having trouble reconciling what happens under the HASH > partitioning!. If I have text column forming the basis of PARTITIONED BY > HASH, the HASH value used in the partitioning setup does not seem to match > to `hashtext()` of that value
It won't match. The hash partition hash is seeded with a special const (HASH_PARTITION_SEED) see [1]. You could likely roll your own hash ops. See [2] for an example. This can then be used to create a hash partitioned table like [3]. [1] https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/backend/partitioning/partbounds.c#l2056 [2] https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/test/regress/sql/insert.sql#l241 [3] https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/test/regress/sql/hash_part.sql#l10 -- David Rowley http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
