Snapshot Information Level Database Application |
API Structure(s) sqlm_dbase sqlm_appl |
Monitor Group Basic Basic |
Resettable |
Yes |
|
Event Information Level Database |
API Structure(s) sqlm_db_event |
|
API Element Name Element Type |
cat_cache_lookups counter |
Description: The number of times that the catalog cache was referenced to obtain table descriptor information.
Usage: This element includes both successful and unsuccessful accesses to the catalog cache. The catalog cache is referenced whenever a table, view, or alias name is processed during the compilation of an SQL statement.
The ratio of catalog cache inserts to catalog cache lookups indicates how successful the catalog cache is at avoiding catalog accesses. If the ratio is small (less than 0.2) then the catalog cache is performing well. A larger ratio may indicate that the catalog cache size should be increased.
You should expect a large ratio immediately following the first connection to the database.
The execution of Data Definition Language (DDL) SQL statements involving a table, view, or alias will evict the table descriptor information for that object from the catalog cache causing it to be re-inserted on the next reference. Therefore, the heavy use of DDLs may also increase the ratio.
See the Administration Guide for more information on the Catalog Cache Size configuration parameter.
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