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:

• Database name: If specified, it must be the current database. In Eon Mode databases, the database name is valid only if the object is in the default namespace.
• Namespace name (Eon Mode only): You must specify the namespace of objects in non-default namespaces. If no namespace is provided, Vertica assumes the object is in the default namespace.

You cannot specify both a database and namespace name.

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.