On Sat, Mar 26, 2011 at 4:17 AM, Tom Lane <t...@sss.pgh.pa.us> wrote:
> "Maxim Boguk" <maxim.bo...@gmail.com> writes: > > In my case vacuum tried to truncate last 10-15GB from 100Gb relation, and > > each time (3) it was cost 10+ minutes of service downtime (because that > > table was completely locked). > > > Is that correct behaviour? Are here any way to speedup that process or > at > > least allow read-only queries during that time? > > Use autovacuum --- if there's something that wants to access the table, > autovac will get kicked off the lock. (Of course, the table may never > get truncated then, but maybe you don't care.) > > regards, tom lane > Thank you for an idea. Are having lots empty pages at end of the table can have any negative impact on database performance (assuming I have plenty of free disk space)? In my case these 100Gb table going to be reduced to 20Gb size actual data located at start of the table, so I worry about possible negative impact of having extra 80Gb free space at end of the table. Regards, Maxim
