Snapshot Information Level Database Table Space Application |
API Structure(s) sqlm_dbase sqlm_tablespace sqlm_bp_info sqlm_appl |
Monitor Group Buffer Pool Buffer Pool Buffer Pool Buffer Pool |
Resettable |
Yes |
|
Event Information Level Database Table Space Connection |
API Structure(s) sqlm_db_event sqlm_tablespace_event sqlm_conn_event |
|
API Element Name Element Type |
pool_data_l_reads counter |
Description: Indicates the number of logical read requests for data pages that have gone through the buffer pool.
Usage: This count includes accesses to data that is:
In conjunction with "Buffer Pool Data Physical Reads", you can calculate the data page hit ratio for the buffer pool using the following formula:
1 - (buffer pool data physical reads / buffer pool data logical reads)
In conjunction with "Buffer Pool Data Physical Reads", "Buffer Pool Index Physical Reads", and "Buffer Pool Index Logical Reads", you can calculate the overall buffer pool hit ratio using the following formula:
1 - ((buffer pool data physical reads + buffer pool index physical reads)
/ (buffer pool data logical reads + buffer pool index logical reads))
If the hit ratio is low (close to zero), increasing the number of buffer pool pages may improve performance. See the Administration Guide for more information about the buffer pool configuration parameter (buffpage).
| Note: | You should use the buffer pool information given at the database level, since the buffer pool size is configured at the database level. However, if the buffer pool hit ratio is low at the application-connection level, it may indicate the reason why that application has poorer performance when compared to other applications connecting to the same database. |
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