SQL/MX 2.x Reference Manual (H06.10+, J06.03+)

Metadata Tables
HP NonStop SQL/MX Reference Manual—544517-008
10-64
Query Plan Caching
For more information about query optimization, see the SQL/MX Query Guide.
Query Plan Caching
These attributes enable NonStop SQL/MX to cache query plans:
Note. The CHECK_CONSTRAINT_PRUNING, MULTIUNION, and
UNION_TRANSITIVE_PREDICATES CQDs are available only on systems running J06.08 and
later J-series RVUs and H06.19 and later H-series RVUs.
Attribute Setting
QUERY_CACHE Set to a value between 0 to 4194303. Indicates the size
in kilobytes to which the cache is allowed to grow.
The default setting is 1024, which activates a query
cache that can grow to 1024 KB in the current session.
To deactivate the query cache in the current session,
set QUERY_CACHE to 0. If a query cache was
allocated, this setting frees it.
For additional information about this setting, see the
SQL/MX Query Guide.
QUERY_CACHE_MAX_VICTIMS Set to a value between 0 and 4194303. Indicates the
maximum number of cache entries that can be
displaced to accommodate a new entry and stay within
the size limit of the cache. Setting this attribute to a very
large value means that all the cache entries could be
displaced to accommodate one very large query.
Setting this attribute to 0 means that, when the cache
becomes full, no cache entries (pinned or unpinned)
can be displaced, and no new entries can be entered
into the cache.
For additional information about this setting, see the
SQL/MX Query Guide.
The default setting is 10 cache entries.