Re: Vacuum full - Mailing list pgsql-general

Thanks Justin,



I suppose the reason for the question is related to the limit on the number
trans before there is a problem.



Regarding the static type app tables I keep referring to.  These tables are
period based. i.e. At the end of the period these tables are loaded and
vacuumed, then used for reporting purposes only.  In the next/new period a
new table will be created added to/updated, then closed at the end of the
period.  The tables are dynamically accessed using "execute" based on the
period selected in the report criteria requested by the user from the GUI.



The tables in question will never change from the point when the period is
closed.



Thanks for your help and info.



Andrew


----- Original Message -----
From: "Justin Clift" <justin@postgresql.org>
To: "Andrew Bartley" <abartley@evolvosystems.com>
Cc: <pgsql-general@postgresql.org>
Sent: Wednesday, November 06, 2002 1:50 PM
Subject: Re: [GENERAL] Vacuum full


> Andrew Bartley wrote:
> >
> > Thanks Justin,
> >
> > These tables will be used for reporting only, No update or insert
activity
> > at all.
>
> As a thought, do you mean "no update or *delete* activity at all"?  No
> insert activity would generally mean you have empty tables (unless using
> COPY to gather data).
>
> If you're only adding data, then selecting against that, and not
> updating or deleting records, you should be fine to skip the VACUUM of
> those tables.  Unsure as to whether you'd want to skip a seperate
> ANALYZE of the tables though.
>
>
> > Q1.
> >
> > Once a day
> >
> > All application table indexes are dropped.
> >
> > A vacuum full analyse is executed.
> >
> > Then all app table indexes are created.
>
> Well, that should definitely keep things in check and maintainable.  :)
>
>
> > Q2.
> >
> > We are running.  PostgreSQL 7.2.1 on i686-pc-linux-gnu, compiled by GCC
> > 2.95.4
> >
> > I know we are several versions behind.  Is there a known bug list for
this
> > version?
>
> Hmmm.  Don't remember.  There are overview details of the changes in the
> 7.2.2 and 7.2.3 releases though on the PostgreSQL News page:
>
> http://www.ca.postgresql.org/news.html
>
>
> > I am also aware there is an upper limit on the number of transactions
> > postgres can do before the DB needs vacuuming.  Somthing to do with tran
ids
> > wrapping or something.  Do you know anything about this?
>
> Not my area.  One of the more-hard-core developers will be able to tell
> you about this though.  From memory though it happens around the 2 or 4
> billionth transaction mark, and something may have been done about it
> for the upcoming 7.3 release (we're in beta testing of this at present).
>
> Hope that helps.
>
> :-)
>
> Regards and best wishes,
>
> Justin Clift
>
> > Thanks
> >
> > Andrew
> >
> > ----- Original Message -----
> > From: "Justin Clift" <justin@postgresql.org>
> > To: "Andrew Bartley" <abartley@evolvosystems.com>
> > Cc: <pgsql-general@postgresql.org>
> > Sent: Wednesday, November 06, 2002 1:02 PM
> > Subject: Re: [GENERAL] Vacuum full
> >
> > > Hi Andrew,
> > >
> > > How much activity do you have on these archive type of tables?  If you
> > > run SELECT queries on them a lot, and you're often updating or
deleting
> > > rows (am specifically not meaning INSERTing new rows) then it might be
> > > worthwhile VACUUMing them.
> > >
> > > Otherwise, it looks like you might not gain much from doing so.  :)
> > >
> > > As a curiosity question, when you VACUUM, do you use the ANALYZE
option?
> > >
> > > As a second curiosity question, when you mention PostgreSQL 7.2, do
you
> > > mean 7.2 literally or 7.2.3?  7.2.3 is the recommended production
> > > version due to bugs having been found in 7.2.2 and 7.2.1.
> > >
> > > Hope that helps.
> > >
> > > :-)
> > >
> > > Regards and best wishes,
> > >
> > > Justin Clift
> > >
> > >
> > > Andrew Bartley wrote:
> > > >
> > > > We are using postgres 7.2
> > >
> > >
> > >
> > > Can anyone tell me what the ramifications are if I do not vacuum full
> > > the whole DB?
> > >
> > >
> > >
> > > Say if I was to selectively vacuum all of the PG tables, and only some
> > > of the Application tables.
> > >
> > >
> > >
> > > We have a number of tables that are effectively archive type tables.
> > > They are large, but do not change. If
> > >
> > > I was to vacuum these tables on a regular basis, it would add a
> > > significant portion of time to the housekeeping process.
> > >
> > >
> > >
> > > Thanks
> > >
> > > Andrew
> > >
> > > --
> > > "My grandfather once told me that there are two kinds of people: those
> > > who work and those who take the credit. He told me to try to be in the
> > > first group; there was less competition there."
> > >    - Indira Gandhi
> > >
> > >
>
> --
> "My grandfather once told me that there are two kinds of people: those
> who work and those who take the credit. He told me to try to be in the
> first group; there was less competition there."
>    - Indira Gandhi
>
>