Horton

Re: Parallel bitmap heap scan

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
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: 2017-03-08T18:22:18Z
Lists: pgsql-hackers 
On Wed, Mar 8, 2017 at 1:18 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
>> What I'm using is:
>
>> Configured with:
>> --prefix=/Applications/Xcode.app/Contents/Developer/usr
>> --with-gxx-include-dir=/usr/include/c++/4.2.1
>> Apple LLVM version 7.0.2 (clang-700.1.81)
>> Target: x86_64-apple-darwin14.5.0
>> Thread model: posix
>
> Hm.  I noticed that longfin didn't spit up on it either, despite having
> -Werror turned on.  That's a slightly newer version, but still Apple's
> clang:
>
> $ gcc -v
> Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
> Apple LLVM version 8.0.0 (clang-800.0.42.1)
> Target: x86_64-apple-darwin16.4.0
> Thread model: posix
> InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

Yeah.  I think on my previous MacBook Pro, you could do this without
generating a warning:

int x;
printf("%d\n", x);

The compiler on this one detects that case, but that seems to be about
as far as it goes.

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

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.