Analyze and Solaris

[brhynold]

I found this in another post about analyzing stats and its something I have never heard of before. Has anyone else ever experienced this. We are in the middle of optimizing a bunch of queries on Solaris and we are finding that by adding the RULE hint instead of FIRST_ROWS we can reduce the execution time by almost 75%

Originally posted by gandolf989
I might add that having stats and optimizer mode set to choose can cause different results on different platforms. I have never had good results generating stats on Solaris Platforms. IMHO Oracle on Solaris needs to run using RBO.

[gandolf989]

If your improvement is really 75% why don't you just set optimizer mode to rule and eliminate the use of the cbo. Someone told me that the Disk IO on Solaris is slower than on other platforms. I don't have any proof of this, just an observation that stats do not work on Solaris. It seems that you agree with that statement.

[brhynold]

After the last couple of days I agree totally with the statement. If we keep getting queries from development, changing the optimizer to RULE will definitely have to be looked at.

[marist89]

Originally posted by gandolf989
If your improvement is really 75% why don't you just set optimizer mode to rule and eliminate the use of the cbo. Someone told me that the Disk IO on Solaris is slower than on other platforms.

I/O performance is more a factor of the hardware involved, not the OS that's driving it.

I don't have any proof of this, just an observation that stats do not work on Solaris.

I have not found this to be the case.

[gandolf989]

I have noticed the stats issue on a Solaris E450 as well as an Ultra Sparc 1. IMHO I think the issue deals with how solaris handles IO not the hardware.

Jeff if you are getting good performance running choose or cbo on Solaris then maybe you are computing stats differently. Or maybe you are dealing with cleaner DML than I am dealing with.