From: | Greg Sabino Mullane <htamfids(at)gmail(dot)com> |
---|---|
To: | "Wong, Kam Fook (TR Technology)" <kamfook(dot)wong(at)thomsonreuters(dot)com> |
Cc: | pgsql-general <pgsql-general(at)lists(dot)postgresql(dot)org> |
Subject: | Re: Will hundred of thousands of this type of query cause Parsing issue |
Date: | 2024-09-13 19:04:40 |
Message-ID: | CAKAnmmKbnPSpzJ45N5314=nFDUtsAjwVPkxLCm87v_3qs9z09A@mail.gmail.com |
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On Fri, Sep 13, 2024 at 11:35 AM Wong, Kam Fook (TR Technology) <
kamfook(dot)wong(at)thomsonreuters(dot)com> wrote:
> 1) Where does query parsing occur?
>
>
Always on the server side, although your driver may do something as well.
2) Will this cause extra parsing to the posgress DB?
>
Yes
> Any pg system table to measure parsing?
>
No
You want to send an array of values to the same query, so it can be
prepared once, like so:
SELECT abc, efg
FROM docloc a
JOIN collection b USING (collection_name)
WHERE a.column1 = ANY($1)
AND a.stage_id = (
select max(stage_id) from collection_pit c
where c.collection_name = a.collection_name
and c.pid_id < $2 and c.stage_code = $3
);
Then you can always pass in three arguments, the first being an array of
all the column1 values you want.
You might also want to get familiar with plan_cache_mode:
https://www.postgresql.org/docs/current/sql-prepare.html
Cheers,
Greg
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