Horton

Re: [POC] hash partitioning

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>
Cc: amul sul <sulamul@gmail.com>, Yugo Nagata <nagata@sraoss.co.jp>, David Steele <david@pgmasters.net>, Greg Stark <stark@mit.edu>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2017-05-10T16:43:20Z
Lists: pgsql-hackers 
On Wed, May 10, 2017 at 8:34 AM, Ashutosh Bapat
<ashutosh.bapat@enterprisedb.com> wrote:
> Hash partitioning will partition the data based on the hash value of the
> partition key. Does that require collation? Should we throw an error/warning if
> collation is specified in PARTITION BY clause?

Collation is only relevant for ordering, not equality.  Since hash
opclasses provide only equality, not ordering, it's not relevant here.
I'm not sure whether we should error out if it's specified or just
silently ignore it.  Maybe an ERROR is a good idea?  But not sure.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

  1. Refactor get_partition_for_tuple a bit.

  2. Adopt Bob Jenkins' improved hash function for hash_any(). This changes the

  3. Improve hash_any() to use word-wide fetches when hashing suitably aligned