Re: autovacuum: 50% iowait for hours

Joao Ferreira <joao(dot)miguel(dot)c(dot)ferreira(at)gmail(dot)com> writes:
> I have a hard situation in hands. my autovacuum does not seem to be able
> to get his job done;

> database is under active INSERTs/UPDATEs;
> CPU is in aprox 50% iowait for the past 5 hours;

> I've tried turning off autovacuum and the effect goes away; I turn it back
> on and it goes back to 50% iowait; my IO system is nothing special at all;

Indeed, it sounds like you don't have enough I/O capacity for the size
of database you are running.

Turning off autovacuum is extremely unlikely to be a good solution;
it might reduce the bandwidth demand but it will just hasten the
database's bloating into unusability.

> 2010-05-13 21:44:59 WEST ERROR: failed to re-find parent key in
> "timeslots_strs_var_ts_key"

You seem to have some worse problems than disk bandwidth, though :-(.
The above is not good at all. What PG version is this? If not recent,
update, then reindex that index.

regards, tom lane