On August 30, 2007 07:38 am, Jan Wieck wrote:
> On 8/22/2007 8:32 PM, Radim Kolar SF.NET wrote:
> > small changes to slony can improve
> > performance a lot during replicating over wan high-latency link.
> >
> > 1. fetch more than 100 lines at once becase fetching over WAN is slow
> >   its easy to compute average line size and then fetch for example +- 1MB
> >   of log lines.
> >
> > 2. Can pgsql use gzip compression for data transfers?
>
> I made good experiences with compressed ssh port forwarding.
>
> > not related to wan but
> > 3. consider to use prepared statements for updating subscribed tables
>
> The problem with prepared statements is that any given log entry might
> touch different columns in the table. So for a table with 8 columns
> there are 255 different possible prepared statements to keep around. In
> reality, an application might show a certain pattern of 4-10 different
> updates per table, but keeping a cache and detecting which statement to
> use when isn't as easy to implement as it is to say "use prepared
> statements".
>
> An idea I had for a future "thing" is to feed the replication log via
> COPY into the replica and have a trigger on that log table interpret it
> and do all the table modifications.

With the ability to do COPY from a query output, this should be fairly trivial 
to implement.


>
>
> Jan

-- 
Darcy Buskermolen
Command Prompt, Inc.
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