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Snapshot Level Database Table Space |
Logical Data Grouping dbase tablespace bp_info |
Monitor Switch Buffer Pool Buffer Pool Buffer Pool |
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Resettable |
Yes |
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Event Type Database Table Space |
Logical Data Grouping db_event tablespace_event |
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Element Name Element Type |
pool_async_data_reads counter |
Description: The number of pages read asynchronously into the buffer pool.
Usage: You can use this element with "Buffer Pool Data Physical Reads" to calculate the number of physical reads that were performed synchronously (that is, physical data page reads that were performed by database manager agents). Use the following formula:
buffer pool data physical reads - buffer pool asynchronous data reads
By comparing the ratio of asynchronous to synchronous reads, you can gain insight into how well the prefetchers are working. This element can be helpful when you are tuning the num_ioservers configuration parameter (see the Administration Guide).
Asynchronous reads are performed by database manager prefetchers. For information about these prefetchers, see the Administration Guide.