Thread: [OT] Slony (initial) Replication - Slow

[OT] Slony (initial) Replication - Slow

From
Ow Mun Heng
Date:
{resend as don't see it on the list after 4 hours}

I'm just wetting my hands with slony and during the setup of the slave,
I did and dump and restore of the master DB to the Slave DB.

However during the startup of slony, I noticed that it issues a truncate
command to the (to be) replicated table. Hence, this means that there's
no such need for me to do a dump/restore in the 1st place.

can someone confirm this? It _is_ taking long time (for slony) to do the
\copy (~60GB in multiple tables being replicated, including (on the fly)
index creation)

Re: [OT] Slony (initial) Replication - Slow

From
Bill Moran
Date:
In response to Ow Mun Heng <Ow.Mun.Heng@wdc.com>:
>
> I'm just wetting my hands with slony and during the setup of the slave,
> I did and dump and restore of the master DB to the Slave DB.
>
> However during the startup of slony, I noticed that it issues a truncate
> command to the (to be) replicated table. Hence, this means that there's
> no such need for me to do a dump/restore in the 1st place.
>
> can someone confirm this?

Confirmed.  It's how Slony is designed to work.

> It _is_ taking long time (for slony) to do the
> \copy (~60GB in multiple tables being replicated, including (on the fly)
> index creation)

1) It only needs to be done once
2) You can remove the indexes from the replica and add them back in after
   the initial sync is complete.

--
Bill Moran
http://www.potentialtech.com

Re: [OT] Slony (initial) Replication - Slow

From
Geoffrey
Date:
Ow Mun Heng wrote:
> {resend as don't see it on the list after 4 hours}
>
> I'm just wetting my hands with slony and during the setup of the slave,
> I did and dump and restore of the master DB to the Slave DB.

You don't need to do this.

> However during the startup of slony, I noticed that it issues a truncate
> command to the (to be) replicated table. Hence, this means that there's
> no such need for me to do a dump/restore in the 1st place.
>
> can someone confirm this? It _is_ taking long time (for slony) to do the
> \copy (~60GB in multiple tables being replicated, including (on the fly)
> index creation)

This is correct.  You want an empty replication database.  When you
start replication slony will bring the master and slave into sync.

--
Until later, Geoffrey

Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety.
  - Benjamin Franklin

Re: [OT] Slony (initial) Replication - Slow

From
Ow Mun Heng
Date:
On Thu, 2008-01-03 at 19:17 -0500, Geoffrey wrote:
> Ow Mun Heng wrote:
> > However during the startup of slony, I noticed that it issues a truncate
> > command to the (to be) replicated table. Hence, this means that there's
> > no such need for me to do a dump/restore in the 1st place.
> >
> This is correct.  You want an empty replication database.  When you
> start replication slony will bring the master and slave into sync.
>

Thanks to you and others who has responded for confirmation.
I would additionally like to know if there was any way for me to use the
dump/restore method and have slony pick up where it was left off?

BTW, it's working right now after some unsuccessful attempts.