RE: wait events and v$session_event

Right. The "global cache *" timed events indicate time spent maintaining the
coherency of the 2+ participating database buffer caches. One note worth
mentioning here is that even the famous "I'll do TP on one RAC node and
query-only on the other" strategy is prone to lots of "global cache *"
activity.

Why? Because of the undo blocks that are used by both nodes.


Cary Millsap
Hotsos Enterprises, Ltd.
http://www.hotsos.com
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-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
On Behalf Of Jamadagni, Rajendra
Sent: Tuesday, May 11, 2004 10:08 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: RE: wait events and v$session_event

RAC Cache fusion waits are not sue to load balancing ... They are due to
the fact that you are running RAC, you will see these waits even if you
are running single node in the RAC.=20

Raj
------------------------------------------------------------------------
--------=20
Rajendra dot Jamadagni at nospamespn dot com=20
All Views expressed in this email are strictly personal.=20
select standard_disclaimer from company_requirements;=20
QOTD: Any clod can have facts, having an opinion is an art !

-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of ryan.gaffuri@xxxxxxx
Sent: Tuesday, May 11, 2004 10:33 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: wait events and v$session_event

I have one batch process running and there are alot of waits. I thought
waits were caused by concurrency?=20

If this is unreadable, please ignore. Hard to format with web email.
Basically, I have large waits for DB_FILE_SCATTERED_READ,
DB_FILE_SEQUENTIAL_READ, and for RAC Cache Fusion due to the load
balancing.=20

     SID EVENT                          TOTAL_WAITS TOTAL_TIMEOUTS
TIME_WAITED AVERAGE_WAIT   MAX_WAIT TIME_WAITED_MICRO
---------- ------------------------------ ----------- --------------
----------- ------------ ---------- -----------------
        22 rdbms ipc reply                          1              0
0            0          0               165
        22 log file sync                            1              0
0            0          0               996
        22 db file sequential read             491250              0
23237            0        172         232371459
        22 db file scattered read              159243              0
29892            0         37         298924960
        22 global cache open x                     10              0
0            0          0              3380
        22 global cache s to x                  11273              0
648            0         42           6477337
        22 global cache cr request            1453244             16
233740            0         98        2337401155
        22 row cache lock                         210              0
14            0          0            135414
        22 library cache lock                      15              0
1            0          0              5311
        22 SQL*Net message to client               21              0
0            0          0                27
        22 SQL*Net message from client             21              0
1            0          0              9023


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