LOCK TABLE

Locks a table, giving the caller's session exclusive access to certain operations. Tables are automatically unlocked after the current transaction ends—that is, after COMMIT or ROLLBACK. LOCK TABLE can be useful for preventing deadlocks.

To view existing locks, see LOCKS.

Syntax

LOCK [ TABLE ] [[{namespace. | database. }]schema.]table [,...]
    IN { lock_type } MODE
    [ NOWAIT ]

Parameters

{ namespace. | database. }

Name of the database or namespace that contains table, depending on the mode of the database:

• Eon Mode: name of the namespace to which table belongs. If unspecified, the namespace is assumed to be default_namespace.
• Enterprise Mode: name of the database. If specified, it must be the current database.

schema

Name of the schema, by default public. If you specify the namespace or database name, you must provide the schema name, even if the schema is public.

table

The table to lock.

lock-type

The type of lock, one of the following:

• SHARE

• INSERT

• INSERT VALIDATE

• SHARE INSERT

• EXCLUSIVE

• NOT DELETE

• USAGE

• OWNER

Note

LOCK TABLE does not currently support D (drop partition) locks.

NOWAIT

If specified, LOCK TABLE returns and reports an error immediately if it cannot acquire the lock. Otherwise, LOCK TABLE waits for incompatible locks to be released by their respective sessions, returning an error if the lock is not released after a certain amount of time, as defined by LockTimeout.

Privileges

Required privileges depend on the type of lock requested:

Examples

See Lock examples.