Horton

Re: POC: Sharing record typmods between backends

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Andres Freund <andres@anarazel.de>
Cc: Thomas Munro <thomas.munro@enterprisedb.com>, Dilip Kumar <dilipbalaut@gmail.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2017-08-23T13:45:38Z
Lists: pgsql-hackers 
On Wed, Aug 23, 2017 at 1:46 AM, Andres Freund <andres@anarazel.de> wrote:
> For later commits in the series:
> - Afaict the whole shared tupledesc stuff, as tqueue.c before, is
>   entirely untested. This baffles me. See also [1]. I can force the code
>   to be reached with force_parallel_mode=regress/1, but this absolutely
>   really totally needs to be reached by the default tests. Robert?

force_parallel_mode=regress is a good way of testing this because it
keeps the leader from doing the work, which would likely dodge any
bugs that happened to exist.  If you want to test something in the
regular regression tests, using force_parallel_mode=on is probably a
good way to do it.

Also note that there are 3 buildfarm members that test with
force_parallel_mode=regress on a regular basis, so it's not like there
is no automated coverage of this area.

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

Commits

  1. Remove TupleDesc remapping logic from tqueue.c.

  2. Add support for coordinating record typmods among parallel workers.

  3. Improve division of labor between execParallel.c and nodeGather[Merge].c.

  4. Add minimal regression test for blessed record type transfer.

  5. Consolidate the function pointer types used by dshash.c.

  6. Fix unlikely shared memory leak after failure in dshash_create().

  7. Refactor typcache.c's record typmod hash table.

  8. Add a hash_combine function for mixing hash values.

  9. Backpatch introduction of TupleDescAttr(tupdesc, i).

  10. Partially flatten struct tupleDesc so that it can be used in DSM.

  11. Change tupledesc->attrs[n] to TupleDescAttr(tupledesc, n).