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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Performance Tuning and Backup & Recovery
Sam
Que 3 - I have no idea how the parameters you are passing affect the execution time. That one probably needs more explanation.
Que 5 - You don't say what you are performing backups with. RMAN? System? Hot? I am going to assume that you are doing hot backups (archivelogging) with the O.S. (not RMAN) and logical backups with exports.
The correct answer is that once you change the incarnation that you immediately do a full backup because the prior backups won't be of much use. If you have done a partial (hot) backup that includes the tablespace that was dropped and the needed archive logs, and probably the system tablespace and control file, you should be able to recover the tablespace. You would probably be doing a TSPITR.
Whether the logical backup (export) would be better probably depends on issues like whether that is your only option (depending on what your partial backup backed up), the size of the tablespace, the level of activity, the importance of data loss, etc.
Dennis Williams
DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com
-----Original Message-----
Sent: Tuesday, June 11, 2002 8:24 AM
To: Multiple recipients of list ORACLE-L
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
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-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).
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-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). Received on Tue Jun 11 2002 - 12:43:45 CDT
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