Re: Feature freeze date for 8.1 - Mailing list pgsql-hackers

From Christopher Browne
Subject Re: Feature freeze date for 8.1
Date
Msg-id m3ekctkz61.fsf@knuth.cbbrowne.com
Whole thread Raw
In response to Feature freeze date for 8.1  (Bruce Momjian <pgman@candle.pha.pa.us>)
Responses Re: Feature freeze date for 8.1  ("Marc G. Fournier" <scrappy@postgresql.org>)
List pgsql-hackers
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
tuplesfrom 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
applicationtransactions (e.g. - invoices or such) were   issued in the last 60 seconds (monitoring a sequence could be
goodenough).
 
-- 
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