Re: vacuumdb --freeze

Zeugswetter Andreas OSB sIT wrote:
> 
> > > > I would like to add a --freeze parameter to vacuumdb for use by the
> > > > binary upgrade utility, and for symmetry with the existing VACUUM
> > > > options;  patch attached.
> > > 
> > > Exactly what do you think the upgrade utility is going to do with it?
> > > Surely not a database-wide VACUUM FREEZE, if we are hoping that upgrade
> > > is going to be fast.
> > > 
> > > As far as I can see this is a solution looking for a problem.
> > 
> > I didn't go into the use-case.  The way pg_migrator works is to copy the
> > _schema_ from the old database and load it into the new database.  We
> > then need to run vacuum freeze on the schema-only databases because we
> > then move pg_clog from the old database to the new one; so, it is
> > needed, and it will not take long to run.
> 
> My first impulse was the same as Tom's, thanks for the explanation.
> 
> To the filled database case:
> 
> Would it make sense to enhance --table to allow wildcards and remove the
> "cannot vacuum a specific table in all databases" check ?
> 
> One more question I have though is: 
> How do you make sure noone (e.g. autovacuum analyze)
> unfreezes tuples after the vacuum freeze ?

I will start a new thread to answer this question, but the short answer
is that the freeze only needs to happen in a fresh initdb database, and
once clog is copied over, new transactions can be created normally.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
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