I understand there must be "some" overhead because we're collecting extra info. I'm curious if there're considerable amount of overhead to the users who don't want such additional trance.
2008/6/16 ITAGAKI Takahiro <[EMAIL PROTECTED]>: > > 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 > -- ------ Koichi Suzuki -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
