Horton

Re: tableam vs. TOAST

Prabhat Sahu <prabhat.sahu@enterprisedb.com>

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From: Prabhat Sahu <prabhat.sahu@enterprisedb.com>
To: Robert Haas <robertmhaas@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2019-07-09T04:40:11Z
Lists: pgsql-hackers 
On Mon, Jul 8, 2019 at 9:06 PM Robert Haas <robertmhaas@gmail.com> wrote:

> On Tue, Jun 25, 2019 at 2:19 AM Prabhat Sahu
> <prabhat.sahu@enterprisedb.com> wrote:
> > I have tested the TOAST patches(v3) with different storage options
> like(MAIN, EXTERNAL, EXTENDED, etc.), and
> > combinations of compression and out-of-line storage options.
> > I have used a few dummy tables with various tuple count say 10k, 20k,
> 40k, etc. with different column lengths.
> > Used manual CHECKPOINT option with (checkpoint_timeout = 1d,
> max_wal_size = 10GB) before the test to avoid performance fluctuations,
> > and calculated the results as a median value of a few consecutive test
> executions.
>
> Thanks for testing.
>
> > All the observation looks good to me,
> > except for the "Test1" for SCC UPDATE with tuple count(10K/20K), for SCC
> INSERT with tuple count(40K)  there was a slightly increse in time taken
> > incase of "with patch" result. For a better observation, I also have ran
> the same "Test 1" for higher tuple count(i.e. 80K), and it also looks fine.
>
> Did you run each test just once?  How stable are the results?
>
No, I have executed the test multiple times(7times each) and calculated the
result as the median among those,
and the result looks stable(with v3 patches).

-- 

With Regards,

Prabhat Kumar Sahu
Skype ID: prabhat.sahu1984
EnterpriseDB Software India Pvt. Ltd.

The Postgres Database Company

Commits

  1. tableam: New callback relation_fetch_toast_slice.

  2. tableam: Allow choice of toast AM.

  3. Move heap-specific detoasting logic into a separate function.

  4. Code cleanup for toast_fetch_datum and toast_fetch_datum_slice.

  5. Rename some toasting functions based on whether they are heap-specific.

  6. Create an API for inserting and deleting rows in TOAST tables.

  7. Split tuptoaster.c into three separate files.

  8. tableam: Move heap-specific logic from needs_toast_table below tableam.