Robert Treat <[EMAIL PROTECTED]> wrote: > On Friday 13 June 2008 12:58:22 Josh Berkus wrote: > > I can see how this would be useful, but I can also see that it could be a > > huge performance burden when activated. So it couldn't be part of the > > standard statistics collection. > > A lower overhead way to get at this type of information is to quantize dtrace > results over a specific period of time. Much nicer than doing the whole > logging/analyze piece.
DTrace is disabled in most installation as default, and cannot be used in some platforms (especially I want to use the feature in Linux). I think DTrace is known as a tool for developers, but not for DBAs. However, statement logging is required by DBAs who used to use STATSPACK in Oracle. I will try to measure overheads of logging in some implementation: 1. Log statements and dump them into server logs. 2. Log statements and filter them before to be written. 3. Store statements in shared memory. I know 1 is slow, but I don't know what part of it is really slow; If the reason is to write statements into disks, 2 would be a solution. 3 will be needed if sending statements to loggger itself is the reason of the overhead. Regards, --- ITAGAKI Takahiro NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
