Horton

Re: Parallel bitmap heap scan

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Jeff Janes <jeff.janes@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, Thomas Munro <thomas.munro@enterprisedb.com>, Haribabu Kommi <kommi.haribabu@gmail.com>, Rafia Sabih <rafia.sabih@enterprisedb.com>, tushar <tushar.ahuja@enterprisedb.com>, Amit Khandekar <amitdkhan.pg@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, Andres Freund <andres@anarazel.de>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2017-03-08T17:53:23Z
Lists: pgsql-hackers 
Robert Haas <robertmhaas@gmail.com> writes:
> On Wed, Mar 8, 2017 at 12:45 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Jeff Janes <jeff.janes@gmail.com> writes:
>>> I'm getting some compiler warnings in gcc version 4.4.7 20120313 (Red Hat
>>> 4.4.7-17) (GCC):

>> Me too.  Fix pushed.

> Thanks.  Sorry for the hassle; my compiler isn't as picky about this
> as I would like, and apparently Dilip's isn't either.

Might be interesting to see whether -O level affects it.  In principle,
whether you get the warning should depend on how much the compiler has
analyzed the logic flow ...

			regards, tom lane

Commits

  1. Pass DSA_ALLOC_HUGE when allocating a shared TIDBitmap.

  2. Support parallel bitmap heap scans.

  3. tidbitmap: Support shared iteration.

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

  5. Revise the way the element allocator for a simplehash is specified.

  6. Refactor bitmap heap scan estimation of heap pages fetched.

  7. Use more efficient hashtable for tidbitmap.c to speed up bitmap scans.