Horton

Re: WIP: [[Parallel] Shared] Hash

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Thomas Munro <thomas.munro@enterprisedb.com>
Cc: Rafia Sabih <rafia.sabih@enterprisedb.com>, Andres Freund <andres@anarazel.de>, Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>, Haribabu Kommi <kommi.haribabu@gmail.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2017-03-22T02:28:09Z
Lists: pgsql-hackers 
On Tue, Mar 21, 2017 at 7:18 PM, Peter Geoghegan <pg@bowt.ie> wrote:
>> As shown in 0008-hj-shared-buf-file-v8.patch.  Thoughts?
>
> A less serious issue I've also noticed is that you add palloc() calls,
> implicitly using the current memory context, within buffile.c.
> BufFileOpenTagged() has some, for example. However, there is a note
> that we don't need to save the memory context when we open a BufFile
> because we always repalloc(). That is no longer the case here.

Similarly, I think that your new type of BufFile has no need to save
CurrentResourceOwner, because it won't ever actually be used. I
suppose that you should at least note this in comments.


-- 
Peter Geoghegan

Commits

  1. Add shared tuplestores.

  2. Remove BufFile's isTemp flag.

  3. Provide DSM segment to ExecXXXInitializeWorker functions.

  4. Optimize joins when the inner relation can be proven unique.

  5. Fix failure to use clamp_row_est() for parallel joins.

  6. Document lack of validation when attaching foreign partitions.

  7. Fix inclusions of c.h from .h files.

  8. Fix inclusions of postgres_fe.h from .h files.

  9. Bring plpgsql into line with header inclusion policy.

  10. Document intentional violations of header inclusion policy.

  11. Shut down Gather's children before shutting down Gather itself.

  12. btree: Support parallel index scans.

  13. Add explicit ORDER BY to a few tests that exercise hash-join code.

  14. Revise hash join code so that we can increase the number of batches

  15. Rewrite hash join to use simple linked lists instead of a