Re: Streaming replica hangs periodically for ~ 1 second - how to diagnose/debug

On Fri, Aug 22, 2025 at 05:07:09PM +0200, Pavel Stehule wrote:
> > Any idea on what could it be?
> Few years ago I had a similar experience - some sec mystic lags - the
> problem was in virtualization.

While I can't discount this idea, after all it is aws ec2, so virtual
boxes, what makes me wonder is:

in case of this slow situation there is futex call, which takes
a second. But there are no futex calls in any other query processing
logs.

So, while it is obvious that futex "wasted" this time, the question is:
why would pg run futex() for this one query at all?

Best regards,

depesz