Re: Logical IO
From: Yong Huang <yong321_at_yahoo.com>
Date: Thu, 19 Nov 2009 09:50:13 -0800 (PST)
Message-ID: <833802.97473.qm_at_web80602.mail.mud.yahoo.com>
> that the only way to find the current mode read is either use
> event 10046 (when the blocks are not already cached) or check
> x$bh for increase in touch count (class 4 for segment header,
> verify with file and block number). There's no event to trace
> CU read.
Date: Thu, 19 Nov 2009 09:50:13 -0800 (PST)
Message-ID: <833802.97473.qm_at_web80602.mail.mud.yahoo.com>
> that the only way to find the current mode read is either use
> event 10046 (when the blocks are not already cached) or check
> x$bh for increase in touch count (class 4 for segment header,
> verify with file and block number). There's no event to trace
> CU read.
I posted that before I read Fuyuncat's posting at
http://www.hellodba.com/Doc/logic_io_secret_FTS_1.html
It looks like setting _trace_pin_time to non-zero unambiguously pinpoints the buffers read in current mode. Excellent!
BTW, for the benefit of others, the meanings of some of the logical I/O functions Fuyuncat used are explained at http://www.jlcomp.demon.co.uk/buffer_usage.html
Yong Huang
-- http://www.freelists.org/webpage/oracle-lReceived on Thu Nov 19 2009 - 11:50:13 CST