Horton

Re: Parallel bitmap heap scan

Dilip Kumar <dilipbalaut@gmail.com>

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From: Dilip Kumar <dilipbalaut@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, 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: 2017-02-08T10:21:02Z
Lists: pgsql-hackers

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On Wed, Feb 8, 2017 at 3:44 AM, Robert Haas <robertmhaas@gmail.com> wrote:
>>> +#ifndef SH_USE_NONDEFAULT_ALLOCATOR
>>> +
>>
>> That should probably be documented in the file header.
>
> Right.  OK, did that and a few other cleanups, and committed.

I think we need to have prototype for the default allocator outside of
#ifndef SH_USE_NONDEFAULT_ALLOCATOR. Because the file e.g. tidbitmap.c
who wants to use SH_USE_NONDEFAULT_ALLOCATOR will provide the
allocator function definition but it can not have the declaration of
those function as that function take SH_TYPE as input and that will be
only defined once we include the simplehash.h.

So basically we can not declare prototype before including
simplehash.h for allocator. And, if we don't declare we will get
"implicit declaration warning" because simplehash itself is using
those functions.

The solution is simplehash.h, should always declare it, and provide
the definitions only if SH_USE_NONDEFAULT_ALLOCATOR is not defined.
Attached patch does that.


-- 
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com

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.