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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_index_writes counter |
Description: The number of times a buffer pool index page was physically written to disk by either an asynchronous page cleaner, or a prefetcher. A prefetcher may have written dirty pages to disk to make space for the pages being prefetched.
Usage: You can use this element with "Buffer Pool Index Writes" to calculate the number of physical index write requests that were performed synchronously. That is, physical index page writes that were performed by database manager agents. Use the following formula:
buffer pool index writes - buffer pool asynchronous index writes
By comparing the ratio of asynchronous to synchronous writes, you can gain insight into how well the buffer pool page cleaners are performing. This ratio can be helpful when you are tuning the num_iocleaners configuration parameter.
For more information about asynchronous page cleaners, see the Administration Guide.