derby.locks.escalationThreshold

Function

Used by the Derby system at runtime in determining when to attempt to escalate locking for at least one of the tables involved in a transaction from row-level locking to table-level locking.

A large number of row locks use a lot of resources. If nearly all the rows are locked, it might be worth the slight decrease in concurrency to lock the entire table to avoid the large number of row locks.

For more information, see "Locking and performance" in Tuning Derby.

It is useful to increase this value for large systems (such as enterprise-level servers, where there is more than 64 MB of memory), and to decrease it for very small systems (such as palmtops).

Syntax

derby.locks.escalationThreshold=numberOfLocks

Default

5000.

Minimum value

100.

Maximum value

2,147,483,647.

Example

-- system-wide property
derby.locks.escalationThreshold=1000
-- database-wide property
CALL SYSCS_UTIL.SYSCS_SET_DATABASE_PROPERTY(
    'derby.locks.escalationThreshold',
    '1000')

Dynamic or static

Dynamic; the change takes effect immediately. For information about dynamic changes to properties, see Dynamic and static properties.