open index spinlock ratio specifies the number of index metadata descriptors that are protected by one spinlock.
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Summary Information |
|
|---|---|
|
Default value |
100 |
|
Range of values |
1–214748364 |
|
Status |
Dynamic |
|
Display level |
Comprehensive |
|
Required role |
System administrator |
|
Configuration groups |
Memory Use, Meta-Data Cache |
SAP ASE uses a spinlock to protect an index descriptor, since more than one process can access the contents of the index descriptor. open index spinlock ratio is used only in multiprocessing systems.
The value specified for this parameter defines the ratio of index descriptors per spinlock.
If one spinlock is shared by too many index descriptors, it can cause spinlock contention. Use sp_sysmon to get a report on spinlock contention. See the Performance and Tuning Series: Monitoring SAP Adaptive Server with sp_sysmon.
If sp_sysmon output indicates an index descriptor spinlock contention of more than 3 percent, try decreasing the value of open index spinlock ratio.
See System Administration Guide: Volume 2 > Managing Mulitprocessor Servers.