Sybase ASE 16.0 Restart versus Backup Restore Issue

[former_member341741]

I am new to Sybase ASE and trying to resolve a mysterious issue. I run a certain SAP benchmark on Sybase ASE to get good performance. At a certain point I backup the database using 'dump database ...' and do two different things: (a) restart SAP and ASE and then run the benchmark, (b) stop SAP, restore the backup using 'load database ...', start SAP, and run the benchmark again. My assumption is (based on my limited knowledge on ASE) that the benchmark should behave the same way in cases (a) and (b). But in reality the benchmark performance in case (b) is really bad compared with case (a). When I looked at the statistics collected by SAP application server it revealed that the statement cache contents for cases (a) and (b) are quite different. I am really puzzled by this. Is my assumption wrong (in that case I am surprised that I cannot save a the database at a state where the benchmark is performing well), or am I missing something during backup/restore procedure? I really appreciate if somebody can help on this.

Regards,

-Priyalal

[former_member198560]

Hi Priyalal,

ASE restart job will start the ASE server only with the system processes.

The restore job will consume the resources like memory , IO to load the database from backup. You can check the RUN_<SID>_BS file for the -m parameter value (if configured). The –m parameter states maximum amount of shared memory in megabytes that Backup Server can use for all of its dump or load sessions. The default shared memory will be 48 MB . You can check with manually configuring the shared memory as below :

1) stop the backup server

2) backup the RUN-<SID>_BS file

3) Add -m 512 (Start with adding 512 MB) at the end of the RUN_<SID>_BS file.

4) Start the backup server

5) Check with restore process .

Please ensure that the configured shared memory to the Backup Server , free available at operating system.

~Gaurav