Re: Parallel bitmap heap scan

From: Dilip Kumar <dilipbalaut(at)gmail(dot)com>
To: Andres Freund <andres(at)anarazel(dot)de>
Cc: pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Parallel bitmap heap scan
Date: 2016-11-30 05:38:55
Views: Raw Message | Whole Thread | Download mbox
Lists: pgsql-hackers

On Fri, Nov 25, 2016 at 6:55 PM, Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
> I have changed the design to directly make it based on DSA instead of using DHT.
> In new version we no longer use DHT. Instead, of that I have made some
> change in simplehash[1], so that it can allow external allocator. In
> tidbitmap.c, I have register the allocator to simplehash and those
> allocator functions will allocate memory directly from DSA.
> simplehash is always using one single memory (during expand it copy
> from old memory to new memory). Which makes remaining processing very
> simple for us.
> In tbm_begin_iterate, we need not to scan complete hash table instead
> of that we can just process dsa memory and convert into page array and
> chunk array.
> I have tested the performance in my local machine and I observed that
> it's slightly better than older
> DHT based version (complete performance number will be published soon).
> Dependency on other patches:
> 1. dsa_area (dsa-v7.patch)
> 2. Creating a DSA area to provide work space for parallel execution
> (dsa-area-for-executor-v3.patch)
> patch details
> 1. hash_support_alloc_free_v1.patch [1].
> 2. parallel-bitmap-heap-scan-v3.patch

I just realised that, my latest patch I just sent to Andres, instead
of replying to all.
Forwarding the same mail to Hackers.

Performance reading with new patch..
TPCH-scale factor 10. work_mem 20MB, Power 4 socket machine

Query Head Patch Improvement
Q4 4811 3290 1.5x
Q6 13136 6198 2.1x
Q14 8119 5057 1.6x
Q15 25652 20143 1.2x

Explained analyzed results are attached with the mail..

* I have also applied Andres patch from below link, for taking this
performance (both for head and for patch).

Dilip Kumar

Attachment Content-Type Size
hash_support_alloc_free_v1.patch application/octet-stream 4.4 KB
parallel-bitmap-heap-scan-v3.patch application/octet-stream 58.2 KB
analyze.tar.gz application/x-gzip 3.7 KB

In response to


Browse pgsql-hackers by date

  From Date Subject
Next Message Michael Paquier 2016-11-30 05:52:35 Re: [PATCH] Reload SSL certificates on SIGHUP
Previous Message Pavel Stehule 2016-11-30 05:30:37 Re: patch: function xmltable