Horton

Re: Hash Functions

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: David Fetter <david@fetter.org>
Cc: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, Tom Lane <tgl@sss.pgh.pa.us>, Andres Freund <andres@anarazel.de>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>, Jeff Davis <pgsql@j-davis.com>, Yugo Nagata <nagata@sraoss.co.jp>, amul sul <sulamul@gmail.com>
Date: 2017-05-13T01:56:30Z
Lists: pgsql-hackers 
On Fri, May 12, 2017 at 7:36 PM, David Fetter <david@fetter.org> wrote:
> On Fri, May 12, 2017 at 06:38:55PM -0400, Peter Eisentraut wrote:
>> On 5/12/17 18:13, Alvaro Herrera wrote:
>> > I think for logical replication the tuple should appear as being in the
>> > parent table, not the partition.  No?
>>
>> Logical replication replicates base table to base table.  How those
>> tables are tied together into a partitioned table or an inheritance tree
>> is up to the system catalogs on each side.
>
> This seems like a totally reasonable approach to pg_dump, especially
> in light of the fact that logical replication already (and quite
> reasonably) does it this way.  Hard work has been done to make
> tuple-routing cheap, and this is one of the payoffs.

Cheap isn't free, though.  It's got a double-digit percentage overhead
rather than a large-multiple-of-the-runtime overhead as triggers do,
but people still won't want to pay it unnecessarily, I think.

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

Commits

  1. Introduce 64-bit hash functions with a 64-bit seed.

  2. Create a "sort support" interface API for faster sorting.

  3. Add seven kanji characters defined in the Windows 950 codepage to our