Well, I did not know that the message was normal while replication was starting.  When I was having the problem, like 10 hours after replicating, one of the sl_log tables had millions of rows and a slony postgres process was continuously at 80% cpu.  I acknowledge it may have been an overreaction to tear the cluster down but after losing the cluster due to a crash, I don't know, it's not very hard to drop and if we start having problems it kills the site pretty fast.

Anyway after regenerating the cluster with a different schema name, not that that had anything to do with it, and waiting, slony has caught up and is now properly truncating / flipping the sl_log_* tables.

Also while this was going on we tried a switchover, which gave us a config error for node -1 (!), and we tried a failover but it just hung.  Now that things seem to be working better, maybe the switchover will go better during tonight's maintenance window.



On Jun 3, 2010, at 10:04 AM, Jan Wieck wrote:

> On 6/3/2010 9:20 AM, Karl Lehenbauer wrote:
>> It does finish, and least I think it does.  I will look very carefully this time to make sure (takes a few hours).
>> This morning I tore the cluster down and recreated it with a different schema name, thinking that might work.  I saw the sl_log_1-not-truncated messages and figured it was hosed, so seeing your message that the logswitch can't happen while there is data that needs to be replicated was heartening.  (It might be good to make a note in the FAQ that those messages are normal when doing the initial subscribe.)
> 
> I am not sure where that idea, that tearing down the whole cluster, is a good response to this issue.
> 
> The reason, why Slony-I cannot finish the log switch, is because of either
> 
> 1) there are still log rows in the segment that need to be replicated.
> 
> or
> 
> 2) transactions that were in progress when the logswitch started are
>   still in progress.
> 
> In case 2) it is possible that such transaction actually did create new log rows, which once the transaction commits of course will need to be replicated.
> 
> 
> Jan
> 
> -- 
> Anyone who trades liberty for security deserves neither
> liberty nor security. -- Benjamin Franklin