Hannu Krosing wrote:

>Hi
>
>When I have three nodes with a set from A being replicated so
>
>A --> B --> C
>
>When are log records deleted from sl_log_1 on node A ?
>
>Is it when they are copied to B or when they are copied to C ?
>
>I have had times when node C is slow, and it seems the the records are
>not deleted from sl_log_1 on A in this case. I this true ?
>  
>
The log records are not purged until they have been received by *ALL*
subscribers.

Otherwise, you would run into the problem that a subscriber could be
left orphaned/stranded in the case where one of the nodes in the chain
fell over.

Suppose the log records were purged on A because they had made it to B,
but they had NOT made it to C...

If B falls over, losing all its data, then there is no way for the data
to get to C, and thus the loss of one subscriber actually leads to the
loss of TWO subscribers.

Slony-I don't do that...