Re: First steps with 8.3 and autovacuum launcher

Tom Lane wrote:
> "Guillaume Smet" <guillaume.smet@gmail.com> writes:
>> So a total of: 16 minutes for 8.2 compared to 53 minutes for 8.3 to
>> have the database in the same state.
> 
> Please try that experiment with all three configurations on both
> versions:
>     * autovacuum off
>     * autovacuum on, autovacuum_vacuum_cost_delay = 0
>     * autovacuum on, autovacuum_vacuum_cost_delay = 20
> Comparing apples and oranges isn't real helpful in determining
> what's happening.

for the record I'm seeing similiar dramatic slowdowns(ie takes a few
additional hours) during restoration of a 120GB database here - with the
default autovacuum settings the restore is taking ages to go through the
ALTER TABLE foo ADD PRIMARY KEY bar steps because autovacuum is
analyzing those tables at a very slow rate (ie the box is more or less
idle and the ALTER TABLE is waiting for the lock).

I have not yet experimented with different autovacuum_vacuum_cost_delay
settings but this seems like a step backwards :-(


Stefan