Re: Partitionining perfortmance degraded drastically after upgrading the database from Oracle 102.0.4 to Oracle 11.2.0.3

  • From: Lothar Flatz <l.flatz@xxxxxxxxxx>
  • To: oracle-l@xxxxxxxxxxxxx
  • Date: Fri, 09 Jan 2015 15:13:12 +0100

Hi Ashoke,
your memory issue look kind of wierd and certainly not correct. It looks like the amount of memory used to be 12 GB in 1o and is now 6 GB. That is certainly not the idea. I usually advise people to set PGA and SGA manually. (Not use memory target.) There are better people than me to answer the memory stuff however. I am no DBA. 
I am performance specialist.
If you have an issue with the PGA your temp waits will have increased.
However it is very difficult to advise if we have no evidence at all. Ideally I would have a sql monitor from one of your slow queries and that would tell me everything. 
Or as a minum send the top 5 wait events from AWR.

Thanks

Lothar


Am 09.01.15 um 14:58 schrieb Mandal, Ashoke:

Greetings All,

I have upgraded one of my 2TB databases with partitioned tables & indexes from 
Oracle 10.2.0.4 to Oracle 11.2.0.3 recently and experiencing severe poor query 
performance. The response time of the queries have increased by 20-25 times.

Before the upgrade to 11g
PGA_AGGREGATE_TARGET=6GB
SGA_TARGET=4GB
SGA_MAX_SIZE=6GB

After the upgrade to 11g
MEMORY_TARGET=6GB
PGA_AGGREGATE_TARGET=0
SGA_TARGET=0
SGA_MAX_SIZE=1GB

My understanding is that if I set SGA_TARGET and PGA_AGGREGATE_TARGET 
parameters to 0 then Oracle manages theses as per the MEMORY_TARGET parameter 
in 11g.
Q. Is it true that the SGA can't grow more than 1GB since SGA_MAX_SIZE is still 
set to 1GB?
Q2. Will the performance improve by setting  SGA_TARGET to 4GB by default?
Q3. Should I also set the PGA_AGGREGATE_TARGET to GB as it was prior the 
upgrade?
Q4. Any known issue of partitioning performance impact after you upgrade a 10g 
database to 11g?

Please let me know if you any suggestions to resolve this issue

Appreciate your help in advance,
Ashoke


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