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Snapshot Level Database Application |
Logical Data Grouping dbase appl |
Monitor Switch Basic Basic |
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Resettable |
Yes |
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Event Type Database Connection |
Logical Data Grouping db_event conn_event |
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Element Name Element Type |
cat_cache_overflows counter |
Description: The number of times that an insert into the catalog cache failed due the catalog cache being full.
Usage: The catalog cache space is filled with table descriptor information.
The cache entries for transactions that compile SQL statements, either by issuing dynamic SQL statements or by binding a package, will not be eligible to be removed from the cache until that transaction has either been committed or rolled back. Catalog cache space is reclaimed by evicting table descriptor information for tables, views, or aliases that are not currently in use by any transaction. Once a transaction has experienced a catalog cache overflow, all subsequent attempts by the same transaction to insert table descriptor information into the catalog cache will also result in an overflow.
| Note: | A transaction involved in an overflow will proceed, but its descriptor information is not inserted into the cache. |
If catalog cache overflows is large, the catalog cache may be too small for the workload. Enlarging the catalog cache may improve its performance. If the workload includes transactions which compile a large number of SQL statements referencing many tables, views, and aliases in a single unit of work, then compiling fewer SQL statements in a single transaction may improve the performance of the catalog cache. Or if it includes binding of packages containing many SQL statements referencing many tables, views or aliases, you can try splitting packages so that they include fewer SQL statements to improve performance.