Re: [COMMITTERS] pgsql: Provide much better wait information in pg_stat_activity. - Mailing list pgsql-hackers

From Pavel Stehule
Subject Re: [COMMITTERS] pgsql: Provide much better wait information in pg_stat_activity.
Date
Msg-id CAFj8pRAthCZZKRwR-+EGbf_SXJBMTVMGj0qMWt312Yg8AbcHdA@mail.gmail.com
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In response to Re: [COMMITTERS] pgsql: Provide much better wait information in pg_stat_activity.  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers


2016-03-11 0:17 GMT+01:00 Tom Lane <tgl@sss.pgh.pa.us>:
Robert Haas <robertmhaas@gmail.com> writes:
> Or ... maybe this is intentional behavior?  Now that I think about it,
> doesn't each backend cache this info the first time its transaction
> reads the data?

Your view of pg_stat_activity is supposed to hold still within a
transaction, yes.  Otherwise it'd be really painful to do any complicated
joins.  I think there may be a function to explicitly flush the cache,
if you really need to see intratransaction changes.

I understand.

This behave has impact on PL functions that try to repeated check of pg_stat_activity. But this use case is not frequent.

Thank you.

Regards

Pavel



                        regards, tom lane

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