While running some tests, I encountered a situation where pgbench gets
stuck in an infinite loop, consuming 100% cpu. The setup was:
- Start postgres server from the master branch
- Initialise pgbench
- Run pgbench -c 10 -T 100
- Stop postgres with -m immediate
That is a strange test to run, but it would be better if the behavior was
not that one.
Now it seems that pgbench gets stuck and it's state machine does not
advance. Attaching it to debugger, I saw that one of the clients remain
stuck in this loop forever.
if (!sendCommand(st, command))
{
/*
* Failed. Stay in CSTATE_START_COMMAND state, to
* retry. ??? What the point or retrying? Should
* rather abort?
*/
As the comments indicate and your situation shows, probably stopping the
client would be a better much option when send fails, instead of
retrying... indefinitely.
The commit that introduced this code is 12788ae49e1933f463bc. So I amn
copying Heikki.
AFAICR the commit was mostly a heavy restructuring of previous
unmaintainable spaghetti code. I'm not sure the problem was not there
before under one form or another.
I agree that it should error out & stop the client in this case at least.
--
Fabien.
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