LOCKS configuration parameter

The LOCKS configuration parameter specifies the initial size of the lock table.

The lock table holds an entry for each lock. If the number of locks allocated exceeds the value of the LOCKS configuration parameter, the database server increases the size of the lock table. The lock table can be increased a maximum of 99 times.

onconfig.std value
LOCKS 20000
values
2,000 through 8,000,000 for 32-bit database servers 2,000 through 500,000,000 for 64-bit database servers
units
Number of locks in the internal lock table
takes effect
After you edit your onconfig file and restart the database server.

Usage

The database server increases the size of the lock table by attempting to double the lock table on each increase. However, the amount added during each increase is limited to a maximum value. For 32-bit platforms, a maximum of 100,000 locks can be added during each increase. Therefore, the total maximum locks allowed for 32-bit platforms is 8,000,000 (maximum number of starting locks) + (99 (maximum number of dynamic lock table extensions) x 100,000 (maximum number of locks added per lock table extension). For 64-bit platforms, a maximum of 1,000,000 locks can be added during each increase. Therefore, the total maximum locks allowed is 500,000,000 (maximum number of starting locks) + (99 (maximum number of dynamic lock table extensions) x 1,000,000 (maximum number of locks added per lock table extension).

With the initial lock table stored in resident memory and each additional lock stored in virtual memory, locks can become a resource drain if you have a limited amount of shared memory. The amount of storage occupied by a single lock depends on the word size and operating system, and is subject to change. Currently, the amount of storage ranges from approximately 100 to 200 bytes. You can see the amount of storage required to support additional locks by restarting the server with a different value of the LOCKS configuration parameter (without making other changes), and observing the increase in memory used as shown by "onstat -g mem" for the resident pool.

Tip: When you drop a database, a lock is acquired and held on each table in the database until the database is dropped.

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