Re: autovacuum with lots of open file references to deleted files

Tore Halset <halset@pvv.ntnu.no> writes:
> On this box I drop a 80GB database each night followed by a restore of a similar sized database. It is a restore of
ourproduction database to a development server. This box is running 9.2rc1 (sorry). 

> du and df reported quite different numbers and lsof show that autovacuum is holding lots of deleted files. After
killingthe autovacuum daemon, some disk space was restored and the du and df numbers was more equal.  

> autovacuum hold roughly 100GB of deleted files. This running PostgreSQL instance has dumped/restored the 80GB
database~20 times. 

Hm.  I've been able to reproduce some leakage of file descriptors in the
autovac launcher, but it required (a) fairly small shared_buffers and
(b) very heavy update activity on large tables.  So I'm not sure that it
would explain the consistent leakage you seem to be seeing.  Can you
tell us more about your usage pattern on the development server?  What
nondefault settings are you using on it?

            regards, tom lane