Re: Performance Improvement by reducing WAL for Update Operation

On 06 December 2013 12:29 Amit Kapila wrote:
> On Fri, Dec 6, 2013 at 12:10 PM, Haribabu kommi
> <haribabu(dot)kommi(at)huawei(dot)com> wrote:
> > On 05 December 2013 21:16 Amit Kapila wrote:
> >> Note -
> >> a. Performance is data is taken on my laptop, needs to be tested on
> >> some better m/c b. Attached Patch is just a prototype of chunkwise
> >> concept, code needs to be improved and decode
> >> handling/test is pending.
> >
> > I ran the performance test on linux machine and attached the results
> in the mail.
>
> This test doesn't make much sense for comparison as in chunkwise delta
> encoding, I am not doing compression using new tuple and the reason is
> that I want to check how good/bad it is as compare to LZ approach for
> cases when data is non-compressible.
> So could you please try to take readings by using patch
> pgrb_delta_encoding_v1 attached in my previous mail.
>
> For LZ delta encoding-
> pgrb_delta_encoding_v1 - In heaptuple.c, there is a parameter
> rabin_fingerprint_comp, set it to false, compile the code and take
> readings.
> This will do LZ compression.
>
> For chunk wise delta encoding - In heaptuple.c, there is a parameter
> rabin_fingerprint_comp, set it to true, compile the code and take
> readings
> This will operate chunk
> wise.

I ran the performance test on above patches including another patch which
Does snappy hash instead of normal hash in LZ algorithm. The performance
Readings and patch with snappy hash not including new data in compression
are attached in the mail.

The chunk wise approach is giving good performance in most of the scenarios.

Regards,
Hari babu.