SQL/MX 2.x Installation and Management Guide (H06.10+, J06.03+)

Reviewing and Setting System Defaults
HP NonStop SQL/MX Installation and Management Guide—544536-007
6-9
Alternative Settings For Selected System Defaults
QUERY_CACHE The default
value is 1024.
The value 0 deactivates the query
cache in the current session.
QUERY_CACHE_MAX_
VICTIMS
The default
value is 10.
A very large value means that all the
cache entries could be displaced to
accommodate one very large query.
A value of 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.
QUERY_CACHE_REQUIRED_
PREFIX_KEYS
The default
value is 255.
A value greater than the number of
columns in a composite key
indicates all columns of the key are
required. The value 0 means that
the presence of any one column of a
composite primary or partition key in
an equality key predicate is
sufficient to make that predicate
cacheable. A value greater than
zero but less than the number of
columns in the key indicates that the
first n columns of the key must be
present in a key predicate for that
predicate to be considered
cacheable.
QUERY_CACHE_
STATEMENT_PINNING
The default
value is OFF.
The value CLEAR means that all
subsequent query cache entries are
unpinned, and all pinned entries in
the cache are also unpinned. The
value ON means that all subsequent
query cache entries into the cache
are pinned.
Table 6-4. Alternative Settings for Selected System Defaults (page3of6)
System Default Default Value Alternative Setting