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Re: Patch: Write Amplification Reduction Method (WARM)

From: Pavan Deolasee <pavan(dot)deolasee(at)gmail(dot)com>
To: Haribabu Kommi <kommi(dot)haribabu(at)gmail(dot)com>
Cc: Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Patch: Write Amplification Reduction Method (WARM)
Date: 2016-11-12 11:12:41
Message-ID: CABOikdPLw=Xer_Oo+vPOtzOKG_7gnH0=rQtL11uEkiUSx5fCSg@mail.gmail.com (view raw, whole thread or download thread mbox)
Thread:
Lists: pgsql-hackers
On Tue, Nov 8, 2016 at 9:13 AM, Haribabu Kommi <kommi(dot)haribabu(at)gmail(dot)com>
wrote:

>
> Thanks for the patch. This shows a very good performance improvement.
>
>
Thank you. Can you please share the benchmark you ran, results and
observations?


> I started reviewing the patch, during this process and I ran the regression
> test on the WARM patch. I observed a failure in create_index test.
> This may be a bug in code or expected that needs to be corrected.
>

Can you please share the diff? I ran regression after applying patch on the
current master and did not find any change? Does it happen consistently?

I'm also attaching fresh set of patches. The first patch hasn't changed at
all (though I changed the name to v5 to keep it consistent with the other
patch). The second patch has the following changes:

1. WARM updates are now tracked separately. We still don't count number of
index inserts separately as suggested by Tomas.
2. We don't do a WARM update if all columns referenced by all indexes have
changed. Ideally, we should check if all indexes will require an update and
avoid WARM. So there is still some room for improvement here
3. I added a very minimal regression test case. But really, it just
contains one test case which I specifically wanted to test.

So not a whole lot of changes since the last version. I'm still waiting for
some serious review of the design/code before I spend a lot more time on
the patch. I hope the patch receives some attention in this CF.

Thanks,
Pavan

-- 
 Pavan Deolasee                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services

Attachment: 0001_track_root_lp_v5.patch
Description: application/octet-stream (27.2 KB)
Attachment: 0002_warm_updates_v5.patch
Description: application/octet-stream (103.5 KB)

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