For SAP ASEs running with multiple engines, lock spinlock ratio sets a ratio that determines the number of lock hash buckets that are protected by one spinlock. If you increase the value for lock hashtable size, the number of spinlocks increases, so the number of hash buckets protected by one spinlock remains the same.
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Summary Information |
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|---|---|
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Default value |
85 |
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Range of values |
1–2147483647 |
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Status |
Static |
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Display level |
Comprehensive |
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Required role |
System administrator |
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Configuration groups |
Lock Manager, Memory Use |
SAP ASE manages the acquiring and releasing of locks using an internal hash table with a configurable number of hash buckets. On SMP systems, this hash table can use one or more spinlocks to serialize access between processes running on different engines. Use lock hashtable size to set the number of hash buckets.
The SAP ASE default value for lock spinlock ratio is 85. With lock hashtable size set to the default value of 2048, the default spinlock ratio defines 26 spinlocks for the lock hash table. See System Administration Guide: Volume 2 > Managing Mulitprocessor Servers.
sp_sysmon reports on the average length of the hash chains in the lock hash table. See the Performance and Tuning Series: Monitoring Adaptive Server with sp_sysmon.