Babu
When building an index, there are 3 (at least) tablespaces that matter:
1. Table tablespace
2. Temp tablespace for sorting
3. Index tablespace (could be the same as the table tablespace)
Ideally you will have all 3 on separate devices. I suspect for your test
cases that sometimes only two devices were involved, which would mean slower
performance.
Also, increase the SORT_AREA_SIZE parameter either in your session or in
init.ora. Then Oracle will need fewer passes to disk during the index build.
Dennis Williams
DBA, 40%OCP, 100% DBA
Lifetouch, Inc.
[EMAIL PROTECTED]
-----Original Message-----
Sent: Thursday, February 20, 2003 1:41 PM
To: Multiple recipients of list ORACLE-L
All
We are doing some performance testing while moving from one server to
another. I was trying to time some index rebuilds and noticed something
that I cant explain.
I am rebuilding an index on a 1 million row table. Lets say its on
tablespace A and when I rebuild it to tablespace B it does in 33 seconds. I
put it back on A and then rebuild it on tablespace C it takes 1 min 40
seconds. The only change here is the target tablespace.
When I set 10046 level 12 and counted time waited (ela column)
>From A - B (33 seconds)
sum of elapsed in "DIRECT PATH READ" = 394 ( i think this is cs)
>From A - C (1 min 40 sec)
sum of elapsed in "DIRECT PATH READ" = 6251
The P1 of all of these waits point to the same file (#4 part of TEMP
tablespace)
Why should the change in the target tablespace affect the time taken to
read from the TEMP tablespace?
TIA
Babu
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