Horton

Re: Parallel bitmap heap scan

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Dilip Kumar <dilipbalaut@gmail.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>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2017-02-07T21:45:18Z
Lists: pgsql-hackers 
On 2017-02-07 16:36:55 -0500, Robert Haas wrote:
> On Tue, Feb 7, 2017 at 4:15 PM, Andres Freund <andres@anarazel.de> wrote:
> > FWIW, I think it'd have been better to not add the new callbacks as
> > parameters to *_create(), but rather have them be "templatized" like the
> > rest of simplehash.  That'd require that callback to check the context,
> > to know whether it should use shared memory or not, but that seems fine
> > to me.  Right now this pushes the head of simplehash above a
> > cacheline...
> 
> Something like the attached?

Yes.

> +#ifndef SH_USE_NONDEFAULT_ALLOCATOR
> +

That should probably be documented in the file header.


Thanks!

Andres

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.