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Increase the size of the data page cache
You can increase the size of a database's data page cache, which consists
of the data pages kept in memory. When Derby can access a database page
from the cache instead of reading it from disk, it can return data much more
quickly.
The default size of the data page cache is 1000 pages. In a multi-user
environment, or in an environment where the user accesses a lot of data, increase
the size of the cache. You configure its size with the derby.storage.pageCacheSize property. For more information about
how to set this property and how to estimate memory use, see the
"Derby properties" section of
the Derby Reference Manual.
Note: Derby can
run even with a small amount of memory and even with a small data page cache,
although it might perform poorly. Increasing the amount of memory available
to Derby and increasing the size of the data page cache improve performance.
In addition, you might want to prime all the caches
in the background to make queries run faster when the user gets around to
running them.
These caches include:
- The page (user data) cache (described above)
Prime this cache by selecting
from much-used tables that are expected to fit into the data page cache.
- The data dictionary cache
The cache that holds information stored
in the system tables. You can prime this cache with a query that selects from
commonly used user tables.
- The statement cache
The cache that holds database-specific Statements (including PreparedStatements). You
can prime this cache by preparing common queries ahead of time in a separate
thread.
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