On Fri, 29 Apr 2005, Christopher Browne wrote:
> Martha Stewart called it a Good Thing when scrappy@postgresql.org ("Marc G. Fournier") wrote:
>> I know one person was talking about being able to target only those
>> that pages that have changes, instead of the whole table ... but some
>> sort of "load monitoring" that checks # of active connections and
>> tries to find 'lulls'?
>
> I have some "log table purging" processes I'd like to put in place; it
> would be really slick to be able to get some statistics from the
> system as to how busy the DB has been in the last little while.
>
> The nice, adaptive algorithm:
>
> - Loop forever
>
> - Once a minute, evaluate how busy things seem, giving some metric X
>
> -> If X is "high" then purge 10 elderly tuples from table log_table
> -> If X is "moderate" then purge 100 elderly tuples from table
> log_table
> -> If X is "low" then purge 1000 elderly tuples from table
> log_table
>
> The trouble is in measuring some form of "X."
>
> Some reasonable approximations might include:
> - How much disk I/O was recorded in the last 60 seconds?
> - How many application transactions (e.g. - invoices or such) were
> issued in the last 60 seconds (monitoring a sequence could be
> good enough).
Some way of doing a 'partial vacuum' would be nice ... where a VACUUM
could stop after it processed those '10 elderly tuples' and on the next
pass, resume from that point instead of starting from the beginning again
...
----
Marc G. Fournier Hub.Org Networking Services (http://www.hub.org)
Email: scrappy@hub.org Yahoo!: yscrappy ICQ: 7615664