Re: Question about (lazy) vacuum

Ühel kenal päeval, K, 2006-08-23 kell 08:11, kirjutas Greg Stark:
> Hannu Krosing <hannu@skype.net> writes:

> > BTW, I think that CONCURRENT CREATE INDEX should be modified to use long
> > transactions which actually build the index and are ignored by vacuum
> > and short ones which write data to system tables and are not ignored.
> > That way we have one less obstacle for keeping high-update tables in
> > shape.
> 
> Hm, that might be worth thinking about. Note that it locks out vacuum from
> running on the table it's running on so it would only help in allowing other
> tables to be vacuumed effectively. 

Exactly. The whole point of one vacuum not blocking others is to make
sure, that a vacuum on a huge table would not disable vacuuming and
thereby reusing rows of much much smaller tables.

Locking out vacuum on the table itself is ok, as the runtimes of vacuum
and concurrent create index on a same table are in the same order.

-- 
----------------
Hannu Krosing
Database Architect
Skype Technologies OÜ
Akadeemia tee 21 F, Tallinn, 12618, Estonia

Skype me:  callto:hkrosing
Get Skype for free:  http://www.skype.com