[Pgpool-general] pgpool-II documentation

[Tatsuo Ishii]

You'd better to understand what plain PostgreSQL behaves
first. PostgreSQL's behavior in this case depends on what transaction
mode (serializable or read committed) and table locking. For example,
if you want to delay reader until writers completes you could use
table locks with writing. But of coure this will lead to performance
degration and/or "reader starvation".
--
Tatsuo Ishii
SRA OSS, Inc. Japan

> Thanks Ishii.
> 
> 
> I'll take a look. 
> 
> One of my other questions is that for example I have replication on. If for example I have a servlet that uses JDBC that talks to the pgpool, when one user attempts to update a table in the database. Will it ensure that another user that selects an entry in the database will get the latest value?
> 
> What if there is a concurrent write and read (ie read comes in while another user is writing)? Will the read be delayed until the write is finished?
> 
> 
> Thanks,
> Harold
> 
> 
> --- On Wed, 4/8/09, Tatsuo Ishii <ishii at sraoss.co.jp> wrote:
> 
> > From: Tatsuo Ishii <ishii at sraoss.co.jp>
> > Subject: Re: [Pgpool-general] pgpool-II documentation
> > To: rold_50 at yahoo.com
> > Cc: pgpool-general at pgfoundry.org
> > Date: Wednesday, April 8, 2009, 9:03 PM
> > > Hi All,
> > > 
> > > Is there a more in-depth documentation of pgpool?
> > 
> > Before stepping into pgpool internal, it' s best to
> > understand how
> > PostgreSQL frontend/backend protocol works. See
> > "Frontend/Backend
> > Protocol".
> > 
> > > I'm mostly interested in how pgpool does the
> > replication process (how it ensures consistency, especially
> > under load_balance_mode).
> > 
> > There are some explanation in the pgpool-II docs(the latest
> > one
> > is:http://pgpool.projects.postgresql.org/pgpool-II/doc/pgpool-en.html).
> > 
> > 
> > Look into around:
> > http://pgpool.projects.postgresql.org/pgpool-II/doc/pgpool-en.html#config
> > -------------------------------------------------------------------
> > replicate_select
> > 
> >     When set to true, pgpool-II replicate SELECTs. If
> > false, pgpool-II
> >     only sends them to Master DB. Default is false.
> > -------------------------------------------------------------------
> > 
> > and:
> > 
> > http://pgpool.projects.postgresql.org/pgpool-II/doc/load_balance.png
> > 
> > Also I'm going to give a talk at PGCon 2009 in Ottawa.
> > I would like to
> > talk about how pgpool-II tries to keep the consistency
> > among databases.
> > --
> > Tatsuo Ishii
> > SRA OSS, Inc. Japan
> 
> 
>