degradation performances

[TOMAS BERNABEU]

I been updated from 10.20 to 11.00 32 bits. and oracle7.3.4 to oracle8.1.6.
The preformances has been degraded 10-15 %

???? ?????

[A. Clay Stephenson]

Hi Tomas:

I have upgraded from Oracle 7.3.4 to 8.0.6 on 10.20 and actually saw a performance increase.

I have then upgraded from 10.20 8.0.6 to both 11.0 and 11.11 in both 32-bit and 64-bit versions. I saw no real hits there either though in a few cases the 32-bit version was slightly faster than the 64-bit version.

I then upgraded the 8.0.6 11x to 8.1.7 and again saw no significant performance hits.

My best guess is that you have some performance tuning to do in your new environment. You didn't provide any data so it's not possible to offer much definitive advice. The very first place I would look is in dynamic buffer cache - if it is set to the default max_dbc_pct of 50 - that is probably your worst problem. On Oracle boxes I prefer to disable dbc and set bufpages to no more than about ~ 300 MB. In any event, you should set it max_dbc_pct to no more than about 15%.

[TOMAS BERNABEU]

max_dbc_pct is fixed to minimal = 2% and buffers oracle incresed

[A. Clay Stephenson]

Okay Tomas, so much for the easy stuff. I have noticed that both 11x and Oracle 8x require a bit more memory to perform well. If your memory was marginal in the old environment that could account for your performance hit. It's time to do some good old performance analysis. You need to use Glance (or sar -b, sar -d, sar -q, sar -s, top, and vmstat to look at memory usage, pageouts, etc.) In addition you need to gather some Oracle performance data as well. Is the performance ok for local users but bad for network users?
Was your old system using raw/io; new system not? HFS vs. VXFS? It is even possible that you may need to decrease the size of your SGA.

[Sanjay_6]

Hi Tomas,

The degradation in performance could be due to the RAM on your system. If you don't have sufficient RAM, you'll see degradation in performance if you migrate from 10.20 to 11.0. What is your present RAM on the box. Also it could be due to the kernel parameters. tune your kernel parameters for the "General OLTP / Database server system" tuned parameter set.

Here is a link to another performance related question. You may benefit from the replies over there.

http://forums.itrc.hp.com/cm/QuestionAnswer/1,1150,0x1e77abe92dabd5118ff10090279cd0f9,00.html

hope this helps.

thanks