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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Autoextend WAIT statistic?
Dennis,
I did some quick & dirty testing by creating a very small(10M) datafile with a large(2000m) autoextend clause. On the insert, the session was waiting on 'file open' for most of the time. When I did a rollback and reinserted the data, there were no waits (that I saw) on file open.
Interestingly, this wait event does not appear to be accurately tracked in v$session_event. In v$session_wait the seconds in wait (last trapped) was 132. In v$session_event, it shows 0. Okay, gurus, why? Am I missing something in this?
select * from v$session_wait where sid = 14
SID SEQ# EVENT
---------- ----------
P1TEXT P1P1RAW
P2TEXT P2P2RAW
P3TEXT P3 P3RAW WAIT_TIME SECONDS_IN_WAITSTATE
---------------------------------------------------------------- ----------
---------------- ---------- ---------------
14 322 file open
fib 4327126592
0000000101EAB640
iov 4327069760
0000000101E9D840
0 0
00 -1 132
WAITED SHORT TIME
select * from v$session_event where sid = 14
SID EVENT TOTAL_WAITS TOTAL_TIMEOUTS
TIME_WAITED AVERAGE_WAIT MAX_WAIT
---------- ------------------------------ ----------- --------------
----------- ------------ ----------
14 rdbms ipc reply 4 1
210 52.5 205
14 control file sequential read 18 0
16 .888888889 15
14 local write wait 1 0
0 0 0
14 log buffer space 72 0
1242 17.25 82
14 log file switch completion 6 0
250 41.6666667 72
14 log file sync 4 0
61 15.25 28
14 db file sequential read 7 0
1 .142857143 1
14 db file scattered read 164 0
152 .926829268 5
14 db file single write 2 0
1 .5 1
14 file identify 4 0
0 0 0
14 file open 6 0
0 0 0
14 SQL*Net message to client 41 0
0 0 0
14 SQL*Net message from client 40 0
67829 1695.725 19952
Dan Fink
-----Original Message-----
Sent: Tuesday, November 26, 2002 2:30 PM
To: Multiple recipients of list ORACLE-L
Oracle says that when a file autoextends, there is a slight delay. Does anyone know which Oracle WAIT statistic that would appear under? We have been using autoextend on OLTP production tables for awhile now, and the results have been satisfactory. This is an ERP system, so the critical performance time is at month-end. Some of the developers are concerned that table autoextending may slow batch programs, and suggesting that I should determine which tables are likely to autoextend during month-end and add storage beforehand. I would like to ensure that I am fixing a real problem (short on time, like most of you), so I am wondering if autoextend was causing a delay, what wait statistic would it show up under. Any ideas?
Dennis Williams
DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com
-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: DENNIS WILLIAMS INET: DWILLIAMS_at_LIFETOUCH.COM Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting servicesReceived on Tue Nov 26 2002 - 17:25:40 CST
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