Sorry for the late reply,
thx a lot all of u for the help
Regards
Sameer
--- "Godlewski, Melissa"
<Melissa.Godlewski_at_hq.doe.gov> 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:sam_orafan_at_yahoo.com]
> 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
>
>
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Author: sam d
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Received on Mon Jun 24 2002 - 23:53:25 CDT
