| Oracle FAQ | Your Portal to the Oracle Knowledge Grid | |
 |
 | |||
| Oracle FAQ | Your Portal to the Oracle Knowledge Grid | |
|
| |||
Home -> Community -> Mailing Lists -> Oracle-L -> 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
-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: sam d INET: sam_orafan_at_yahoo.com 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: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-LReceived on Tue Jun 11 2002 - 08:23:38 CDT
(or the name of mailing list you want to be removed from). You may
also send the HELP command for other information (like subscribing).
 |
 |