On 5/23/21 12:04 AM, Soumya Prasad Ukil wrote:
postgres=> execute parallel_execute1('a', 'b');
postgres=> execute parallel_execute2(1, 2);
I have enabled pg_stats_statement chrome extension. I have enabled
postgres log inside post_parse_analyze_hook
and also debugging through gdb using break point. I see it is always
going through parse callback. But when I use the same sql statement
using Java program through JDBC prepare statement, it does not go to
parse callback all the time. It stops after 6th iteration onwards. What
I have read in JDBC is that, postgres has a default threshold for
prepare statement to 5
https://jdbc.postgresql.org/documentation/head/server-prepare.html
<https://jdbc.postgresql.org/documentation/head/server-prepare.html>.
But after 6th statement onwards, what I see parse callback is not
triggered. However the same does not happen in psql command line. If I
execute the same statement 10 times, all the times it goes through
parsing. Not sure what JDBC does extra.
Take a look at the Notes section here:
https://www.postgresql.org/docs/current/sql-prepare.html
It goes into detail on how a PREPARE statement is handled as regards
parsing. See if the conditions mentioned there cover your psql case or not.
On Sunday, 23 May, 2021, 03:53:55 am IST, Adrian Klaver
<adrian.klaver@xxxxxxxxxxx> wrote:
On 5/22/21 1:25 PM, Soumya Prasad Ukil wrote:
> I have been using postgres prepare statement feature through JDBC. I
> could see the same prepare statement multiple times, parsing is not
> happening in postgres backend, which is expected. However I do the same
> in psql command line, that does not happen. It goes to parsing every
> time I execute
>
> Using the following query:
>
> postgres=> PREPARE parallel_execute1(text, text) AS insert into actor
> (first_name, last_name) values ($1, $2);
> postgres=> PREPARE parallel_execute2(int, int) AS insert into film_actor
> (actor_id, film_id) values($1, $2);
> postgres=> execute parallel_execute1;
> postgres=> execute parallel_execute2;
Where are the arguments for the parameters?
>
>
> I have executed both prepared statements 10 times. I could see every
> time both queries went through parsing. How do I make sure that they do
> not need parsing in command line? JDBC it works in expected manner. Same
> code does not go for parsing each time. How can I have same behaviour in
> pgsql command line?
>
How are you determining the above?
--
Adrian Klaver
adrian.klaver@xxxxxxxxxxx <mailto:adrian.klaver@xxxxxxxxxxx>
--
Adrian Klaver
adrian.klaver@xxxxxxxxxxx
