Horton

Re: WIP: [[Parallel] Shared] Hash

Thomas Munro <thomas.munro@enterprisedb.com>

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From: Thomas Munro <thomas.munro@enterprisedb.com>
To: Peter Geoghegan <pg@bowt.ie>
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>, Robert Haas <robertmhaas@gmail.com>
Date: 2017-03-27T06:50:00Z
Lists: pgsql-hackers 
On Sun, Mar 26, 2017 at 3:56 PM, Thomas Munro
<thomas.munro@enterprisedb.com> wrote:
> But... what you said above must be a problem for Windows.  I believe
> it doesn't allow files to be unlinked if they are open, and I see that
> DSM segments are cleaned up in resowner's phase ==
> RESOURCE_RELEASE_BEFORE_LOCKS and files are closed in phase ==
> RESOURCE_RELEASE_AFTER_LOCKS.

I thought this last point about Windows might be fatal to my design,
but it seems that Windows since at least version 2000 has support for
Unixoid unlinkability via the special flag FILE_SHARE_DELETE.

-- 
Thomas Munro
http://www.enterprisedb.com

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