Product Documentation

Database Administrator's Guide

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BLOCKING_LOCK_TIMEOUT_SEC avoids excessively long blocking lock waits. When used, this feature returns error UTIM_OUT (827) to the caller of the lock request. The function ctLOKTIMOUT() is used to set, change and clear this timeout feature.

  • timeoutSEC is specified in seconds, and determines the amount of time to wait before returning the UTIM_OUT error.

This configuration entry is equivalent to a member of the ADMIN group making the call ctLOKTIMOUT(-1, ctLTOallusers | ctLTOdiagnostic, timeoutSEC).

Note: The effect of the configuration entry can be turned off by a call of the form ctLOKTIMOUT(-1, ctLTOallusers, 0).

If a user calls ctLOKTIMOUT() with a datno equal to -1 in order to set a timeout value on all data files for the user, the user can selectively change or turn off the timeout by making additional calls to ctLOKTIMOUT() specifying the data file number.

Lock Statistics

Locking statistics have an inconsistency when a lock request is removed from a list of waiting lock requests. When a lock request times out with this new feature, it is removed from the wait list. For instance, if a thread is waiting for a lock and it is killed by ctadmn, the lock is removed from the waiting list, however, the lock statistics do not reflect this. In fact, the count of currently blocked locks will be off (too high) by one for each lock request removed from a wait list. A new lock statistic has been added to account explicitly for lock requests that have been removed from the wait list: “killed.” It is treated in the same manner as the deadlock category.