Version 5
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Version 5
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The aim of the Global SQL Cache is to minimize the amount of catalog access
required for sections of static SQL statements and to maximize the sharing of
sections for dynamic DML statements by eliminating many of the previous
restrictions. This is done by establishing a global cache shared by all
agents connected to the same database or partition of a database (in the case
of DB2 Universal Database Extended Enterprise Edition), in which sections for
both static and dynamic SQL statements will be placed. This global
cache acts as a public repository, or library, for different sections being
used on the database at any given time.
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Version 5.2
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The DB2_NO_PKG_LOCK registry variable allows the Global SQL Cache to operate without the use of package locks to protect cached package entries. In Version 5 package entries in the cache (while in use) were protected from being dropped or modified by cache-level locks. Since acquiring a lock is expensive in terms of performance, users now have the option of working in a no package lock mode. In this mode certain database operations will not be allowed in order to protect cached package entries (for example: DROP TABLE). See the Administration Guide for details.