Re: Parallel bitmap heap scan

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

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