Re: Re: Hot Standby query cancellation and Streaming Replication integration

On 3/10/10 3:38 AM, Greg Stark wrote:
> I think that means that a
> vacuum_defer_cleanup of up to about 100 or so (it depends on the width
> of your counter record) might be reasonable as a general suggestion
> but anything higher will depend on understanding the specific system.

100 wouldn't be useful at all.  It would increase bloat without doing
anything about query cancel except on a very lightly used system.

> With vacuum_defer_cleanup that will no longer be true.
> It will be as if you always have a query lasting n transactions in
> your system at all times.

Yep, but until we get XID-publish-to-master working in 9.1, I think it's
probably the best we can do.  At least it's no *worse* than having a
long-running query on the master at all times.

--Josh Berkus