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help / color / mirror / Atom feedFrom: Alena Rybakina <[email protected]>
To: PostgreSQL-development <[email protected]>
To: Tomas Vondra <[email protected]>
To: Ranier Vilela <[email protected]>
Cc: Marcos Pegoraro <[email protected]>
Cc: Andrey Lepikhov <[email protected]>
Cc: [email protected]
Cc: Peter Geoghegan <[email protected]>
Subject: Re: POC, WIP: OR-clause support for indexes
Date: Wed, 5 Jul 2023 23:06:26 +0300
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
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Sorry, I threw off the wrong charts, I'm sending the right ones.
On 05.07.2023 22:39, Alena Rybakina wrote:
> HI, all!
>
>> On 27.06.2023 16:19, Alena Rybakina wrote:
>>> Thank you for your feedback, your work is also very interesting and
>>> important, and I will be happy to review it. I learned something new
>>> from your letter, thank you very much for that!
>>>
>>> I analyzed the buffer consumption when I ran control regression
>>> tests using my patch. diff shows me that there is no difference
>>> between the number of buffer block scans without and using my patch,
>>> as far as I have seen. (regression.diffs)
>>>
>>>
>>> In addition, I analyzed the scheduling and duration of the execution
>>> time of the source code and with my applied patch. I generated 20
>>> billion data from pgbench and plotted the scheduling and execution
>>> time depending on the number of "or" expressions.
>>> By runtime, I noticed a clear acceleration for queries when using
>>> the index, but I can't say the same when the index is disabled.
>>> At first I turned it off in this way:
>>> 1)enable_seqscan='off'
>>> 2)enable_indexonlyscan='off'
>>> enable_indexscan='off'
>>>
>>> Unfortunately, it is not yet clear which constant needs to be set
>>> when the transformation needs to be done, I will still study in
>>> detail. (the graph for all this is presented in graph1.svg
>
> I finished comparing the performance of queries with converted or
> expressions and the original ones and found that about 500 "OR"
> expressions have significantly noticeable degradation of execution
> time, both using the index and without it (you can look at
> time_comsuption_with_indexes.png and
> time_comsuption_without_indexes.html )
>
> The test was performed on the same benchmark database generated by 2
> billion values.
>
> I corrected this constant in the patch.
>
--
Regards,
Alena Rybakina
Postgres Professional
Attachments:
[image/png] time_comsuption_with_indexes.png (75.6K, ../[email protected]/2-time_comsuption_with_indexes.png)
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[image/png] time_comsuption_without_indexes.png (78.9K, ../[email protected]/3-time_comsuption_without_indexes.png)
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