It'll be in the book (Optimizing Oracle Response Time: O'Reilly), still due out in about June. I'll be working on it pretty much all day, every day through the end of December. I don't consider myself in the same league as Lewis/Adams/Kolk/Wood/Holt/Hailey et al. in the V$ domain, but I do at least have sense enough to ask for their assistance during research and technical review :).
Cary Millsap Hotsos Enterprises, Ltd. http://www.hotsos.com Upcoming events: - Hotsos Clinic, Dec 9-11 Honolulu - Hotsos Clinic 101, Jan 7-9 Knoxville - Steve Adams's Miracle Master Class, Jan 13-15 Copenhagen - 2003 Hotsos Symposium, Feb 9-12 Dallas -----Original Message----- Sent: Wednesday, November 27, 2002 1:59 PM To: Multiple recipients of list ORACLE-L I have heard from several sources that the v$ views are not as solid as they should be. With all the emphasis on wait and event based tuning, they should be more accurate. Has anyone done in-depth research on the collection methods and accuracy of the x$ and v$ structures? Sounds like a project for some of the gurus on the list... <HINT, HINT> -----Original Message----- Sent: Tuesday, November 26, 2002 8:25 PM To: Multiple recipients of list ORACLE-L As much as the v$"wait" views are touted they do have problems. First, I believe they are only updated every 3 seconds and can miss events. Second, examine enough samplings from the tables and you'll discover bizarre data. Events which managed to wait say 50 seconds in a single sampling period when the sampling rate was 5 Hz. On the other hand, one may see events which are continuous over many samplings, but their wait times are not incremented. If you really want to know what's going on there's no substitute for a 10046 trace. N.B., I am not stating the v$"wait" statistics tables are useless just that they have their shortcomings. Ian MacGregor Stanford Linear Accelerator Center [EMAIL PROTECTED] -----Original Message----- Sent: Tuesday, November 26, 2002 3:26 PM To: Multiple recipients of list ORACLE-L 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 P1 P1RAW ---------------------------------------------------------------- ---------- ---------------- P2TEXT P2 P2RAW ---------------------------------------------------------------- ---------- ---------------- P3TEXT P3 P3RAW WAIT_TIME SECONDS_IN_WAIT ---------------------------------------------------------------- ---------- ---------------- ---------- --------------- STATE ------------------- 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. [EMAIL PROTECTED] -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: DENNIS WILLIAMS INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Fink, Dan INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: MacGregor, Ian A. INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Fink, Dan INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Cary Millsap INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
