Sorry for the late reply, thx a lot all of u for the help Regards Sameer --- "Godlewski, Melissa" <[EMAIL PROTECTED]> wrote: > Sam, > > Que1: > If you have statistics on the table then the cost > based optimizer is used. > If you have out of data statistics you could be > sending bad information to > the optimizer for join conditions. Using the > explain plan and plan table > (utlplan.sql in $oracle_home/rdbms/admin) will show > you cost information and > access paths to the data. > > Que2: > The trace file should have a date time stamp that is > near the time you ran > yours. Additionally if you look at the trace file > it will have the osuer > information in it. > > Que3: > It's hard to say the cause. You will need to look > at v$session and > v$session_wait to identify what the session in > waiting for. Is it possible > there was other jobs executing on the system which > slowed down your query > the second time? On NT the perfmon on UNIX top will > give you some > information. You need to know what the waits are. > Additionally you can > trace or dump the session. > > Que4: > Run an explain plan and tk_prof on the session to > find out what objects the > application is using. Verify all the indexes are > there and not dropped > accidentally. You need to find the objects and > verify the access paths the > optimizer is using for the application are the best > ones. Hints or sql > rewrite may be in order. > > Que5: > I'm not sure what you mean by logical backup. Maybe > below suggestions may > work. > Are you using RMAN for backups. If so look into > tablespace recover. If not > restore your backups to a development/test server > recover the tablespace and > associated data. Export/Import to your other > machine. > > > -----Original Message----- > From: sam d [mailto:[EMAIL PROTECTED]] > Sent: Tuesday, June 11, 2002 9:24 AM > To: Multiple recipients of list ORACLE-L > Subject: Performance Tuning and Backup & Recovery > > > Hi, > > I don't have much onhand experience, I thought > list is the appropriate place to get information. > These are related to Oracle Performance Tuning and > Backup & Recovery. > > I have a system of Oracle 8i under HP-Unix and with > ARCHIVELOG on. It has been running and stable since > last 2-3 years. This was a brief overview. > > Que 1: Assuming that I am using Cost based Optimizer > (CBO); I have a query which is a join of three > tables > out of which only one table have been analyzed and > in > first case rest two were analyzed but long time back > and after that I have changed the structure of the > table and in second case the other two tables have > not > been analyzed. Will Oracle use CBO ? I know it will > but then what will be the behavior of optimizer ? > Will > it take the best guess for the other two tables in > both the cases and if yes then those best guesses > will > be depending upon on what ? > > Que 2: Suppose u have ran EXPLAIN PLAN for a > particular query at sqlplus prompt and there are > around 50 more users running EXPLAIN PLAN at the > same > time from the UNIX bos itself. In this case the > OSUSER, TERMINAL, PROGRAM will be same (u know it > better). Now suppose I want to run TKPROF against > the > trace file how will I identify which will be my > trace > file in USER_DUMP_DEST directory ? > > Que 3: Supposing if I have Oracle Report running on > Oracle. I passed 3 parameters first time it took me > around 3 seconds to execute and 4 parameters second > time its hogging the system taking almost 25 minutes > to run. There are no concatenated indexs on the > underlying tables. What might be the cause and how > would u go about identifying it ? > > Que 4: A user starts complaining about a particular > part of an appln. What will be my first steps to > optimize it ? > > Que 5: Let's say we have a situation where at point > "A" I took a complete db backup. Somewhere after > point > "B" I lost an online redo log file. I recovered the > db > using the bck taken at point "A" and archived redo > log > files and started the new incarnation at point "B". > I > took a complete logical backup at point "B" and > taking > incremental backup after that. Now again at point > "C" > I took the complete bck. If I have dropped a > tablespace somewhere in between point B and C which > are the possible ways to recover it and which one > will > be the fastest ? (Of course if possible). > > A---------------B---------------C---------------D > > If I am not clear on any of the part please let me > know and I'll do the needful. > > Thanks > > > __________________________________________________ > Do You Yahoo!? > Yahoo! - Official partner of 2002 FIFA World Cup > http://fifaworldcup.yahoo.com > -- > Please see the official ORACLE-L FAQ: > http://www.orafaq.com > -- > Author: sam d > INET: [EMAIL PROTECTED] > > Fat City Network Services -- (858) 538-5051 FAX: > (858) 538-5051 > San Diego, California -- Public Internet > access / Mailing Lists > -------------------------------------------------------------------- > 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). >
__________________________________________________ Do You Yahoo!? Yahoo! - Official partner of 2002 FIFA World Cup http://fifaworldcup.yahoo.com -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: sam d INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- 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).
