Slony1 PostgreSQL Replication - Slony susceptible to temporary network outages?

Author

Slony susceptible to temporary network outages?

Ujwal S. Setlur

2006-02-03, 3:24 am

Hi,

I have a slony setup going between my laptop and
desktop. The laptop is on a wireless connection which
is sometimes flaky. When the network is restored, I
notice that the slon processes on the origin and
subscriber are out of sync a lot, and don't seem to
get back into sync, as evidenced by a growing
num_lag_events in sl_status.

I have to manually restart the slon processes on the
origin first, then on the subscriber, and then the
slon processes catch up very quickly.

I am running slon 1.1 with a "g" factor of 10000.

Any ideas?

Thanks,

Ujwal

____________________
____________________
__________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com

Darcy Buskermolen

2006-02-03, 3:24 am

On Thursday 02 February 2006 20:55, Ujwal S. Setlur wrote:
> Hi,
>
> I have a slony setup going between my laptop and
> desktop. The laptop is on a wireless connection which
> is sometimes flaky. When the network is restored, I
> notice that the slon processes on the origin and
> subscriber are out of sync a lot, and don't seem to
> get back into sync, as evidenced by a growing
> num_lag_events in sl_status.
>
> I have to manually restart the slon processes on the
> origin first, then on the subscriber, and then the
> slon processes catch up very quickly.
>
> I am running slon 1.1 with a "g" factor of 10000.
>
> Any ideas?

What version of slony ?
>
> Thanks,
>
> Ujwal
>
> ____________________
____________________
__________
> Do You Yahoo!?
> Tired of spam? Yahoo! Mail has the best spam protection around
> http://mail.yahoo.com
> ____________________
____________________
_______
> Slony1-general mailing list
> Slony1-general- AuKwsB3Fm+ugFIWk8tvy
RWD2FQJk+8+b@public.gmane.org
> http://gborg.postgresql.org/mailman.../slony1-general

--
Darcy Buskermolen
Wavefire Technologies Corp.

http://www.wavefire.com
ph: 250.717.0200
fx: 250.763.1759

Ujwal S. Setlur

2006-02-03, 3:24 am

--- Darcy Buskermolen <darcy- QSklyHmfoqpWk0Htik3J
/w@public.gmane.org> wrote:
[color=darkred]
> On Thursday 02 February 2006 20:55, Ujwal S. Setlur
> wrote:
> which
> I
> to
> the
>
>
> What version of slony ?

slony 1.1

Ujwal

____________________
____________________
__________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com

Darcy Buskermolen

2006-02-03, 3:24 am

On Thursday 02 February 2006 21:27, Ujwal S. Setlur wrote:
> --- Darcy Buskermolen <darcy- QSklyHmfoqpWk0Htik3J
/w@public.gmane.org> wrote:
>
> slony 1.1

1.1.what ?

>
> Ujwal
>
> ____________________
____________________
__________
> Do You Yahoo!?
> Tired of spam? Yahoo! Mail has the best spam protection around
> http://mail.yahoo.com
> ____________________
____________________
_______
> Slony1-general mailing list
> Slony1-general- AuKwsB3Fm+ugFIWk8tvy
RWD2FQJk+8+b@public.gmane.org
> http://gborg.postgresql.org/mailman.../slony1-general

--
Darcy Buskermolen
Wavefire Technologies Corp.

http://www.wavefire.com
ph: 250.717.0200
fx: 250.763.1759

Ujwal S. Setlur

2006-02-03, 3:24 am

--- Darcy Buskermolen <darcy- QSklyHmfoqpWk0Htik3J
/w@public.gmane.org> wrote:

> On Thursday 02 February 2006 21:27, Ujwal S. Setlur
> wrote:
> Setlur
> and
> connection
> restored,
> and
> seem
> on
> the
> 10000.
>
> 1.1.what ?

Sorry :-), forgot there is a third digit. I am running
slony 1.1.1

Ujwal

____________________
____________________
__________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com

Michael Crozier

2006-02-03, 3:24 am

> I am running slon 1.1 with a "g" factor of 10000.

As I understand it (somebody please correct me if I'm wrong), a "g" factor
of more than 100 actually impedes "catch up". The code has logic that
resets the sync group to 1 whenever the group size "grows" above 100 (slon
gradually grows to -g size).

If you grep your slony log for "processing", you should see a pattern were
the event being synced gradually increases more from the previous until it
exceeds 100. Once it hits 100, it likely drops back down to zero.

So, try setting '-g 100' and see if the slon eventually makes progress.

-Michael

Darcy Buskermolen

2006-02-03, 3:24 am

On Thursday 02 February 2006 21:44, Ujwal S. Setlur wrote:
> --- Darcy Buskermolen <darcy- QSklyHmfoqpWk0Htik3J
/w@public.gmane.org> wrote:
>
> Sorry :-), forgot there is a third digit. I am running
> slony 1.1.1

1.1.5 has some new network recovery stuff, that should help cope with poor
networks a bit better. Keep in mind that slony was created to operate on
networks where the normal mode of operation is online and available (between
nodes).
>
> Ujwal
>
> ____________________
____________________
__________
> Do You Yahoo!?
> Tired of spam? Yahoo! Mail has the best spam protection around
> http://mail.yahoo.com
> ____________________
____________________
_______
> Slony1-general mailing list
> Slony1-general- AuKwsB3Fm+ugFIWk8tvy
RWD2FQJk+8+b@public.gmane.org
> http://gborg.postgresql.org/mailman.../slony1-general

--
Darcy Buskermolen
Wavefire Technologies Corp.

http://www.wavefire.com
ph: 250.717.0200
fx: 250.763.1759

Sponsored Links