Re: Parallel bitmap heap scan

On Wed, Nov 30, 2016 at 4:38 PM, Dilip Kumar <dilipbalaut@gmail.com> wrote:

> On Fri, Nov 25, 2016 at 6:55 PM, Dilip Kumar <dilipbalaut@gmail.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)
> > https://www.postgresql.org/message-id/CAEepm%3D024p-
> MeAsDmG%3DR3%2BtR4EGhuGJs_%2BrjFKF0eRoSTmMJnA%40mail.gmail.com
> >
> > 2. Creating a DSA area to provide work space for parallel execution
> > (dsa-area-for-executor-v3.patch)
> > https://www.postgresql.org/message-id/CAEepm%3D0HmRefi1%
> 2BxDJ99Gj5APHr8Qr05KZtAxrMj8b%2Bay3o6sA%40mail.gmail.com
> >
> > 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).
> https://www.postgresql.org/message-id/20161123083351.
> 5vramz52nmdokhzz%40alap3.anarazel.de
>
>
Moved to next CF with "needs review" status.

Regards,
Hari Babu
Fujitsu Australia