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Drill down on the Reads line to see the detail I/O activity for each device in the SYBM_DiskIODetail graph view. |
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Drill down on the Reads lines to see the SYBM_DiskIOSemaphores graph view to check if any semaphore contention exists on that device. |
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Open the SYBM_LockSummary graph view to display the number of locks requested on the system, locks that had to wait to be granted, locks that timed out, and the number of deadlocks on the system. |
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Drill down on the locks time out to view the SYBM_LockWaitTime graph view to display the average wait time for locks. Use this chart to discover any specific period of time where the performance noticeably degrades. Investigate respective user and application activity during this time frame using one of the SYBM_ResourcesInUse or one of the SYBM_Top Foglight views. |
System administrators can use sp_configure to change this limit. For example:
You may also need to adjust the sp_configure parameter total memory, since each lock uses memory.
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IMPORTANT: The Adaptive Server uses the metadata cache: When the Adaptive Server opens a database or accesses an index or an object, it needs to read information in the respective system tables: sysdatabases, sysindexes, and sysobjects. The metadata caches for databases, indexes, or objects let the Adaptive Server access the information that describes it in the sysdatabases, sysindexes, or sysobjects row that are directly in its in-memory structure. This improves performance by allowing the Adaptive Server to bypass expensive calls that require disk access. Synchronization and spin lock contention are also reduced when the Adaptive Server has to retrieve database, index, or object information during runtime. |
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