Re: Logging parallel worker draught

Benoit Lobréau <benoit.lobreau@dalibo.com>

From: Benoit Lobréau <benoit.lobreau@dalibo.com>
To: Tomas Vondra <tomas.vondra@enterprisedb.com>, "Imseih (AWS), Sami" <simseih@amazon.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Robert Haas <robertmhaas@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Melanie Plageman <melanieplageman@gmail.com>
Date: 2024-02-29T08:24:20Z
Lists: pgsql-hackers
On 2/27/24 15:09, Tomas Vondra wrote> That is certainly true, but it's 
not a new thing, I believe. IIRC we may
 > not report statistics until the end of the transaction, so no progress
 > updates, I'm not sure what happens if the doesn't end correctly (e.g.
 > backend dies, ...). Similarly for the temporary files, we don't report
 > those until the temporary file gets closed, so I'm not sure you'd get a
 > lot of info about the progress either.
 >
 > I admit I haven't tried and maybe I don't remember the details wrong.
 > Might be useful to experiment with this first a little bit ...

Ah, yes, Tempfile usage is reported on tempfile closure or deletion
for shared file sets.

 > I certainly understand that, and I realize it may feel daunting and even
 > discouraging. What I can promise is that I'm willing to help, either by
 > suggesting ways to approach the problems, doing reviews, and so on.
 > Would that be sufficient for you to continue working on this patch?

Yes, thanks for the proposal, I'll work on it on report here. I am otherwise
booked on company projects so I cannot promise a quick progress.

 > Some random thoughts/ideas about how to approach this:
 >
 > - For parallel workers I think this might be as simple as adding some
 > counters into QueryDesc, and update those during query exec (instead of
 > just logging stuff directly). I'm not sure if it should be added to
 > "Instrumentation" or separately.

I will start here to see how it works.

-- 
Benoit Lobréau
Consultant
http://dalibo.com