MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6

28.3.1 The Locking Service

MySQL distributions provide a locking interface that is available at two levels:

For general information about plugin services, see Section 28.3, “MySQL Services for Plugins”. For general information about user-defined functions, see Section 28.4.2, “Adding a User-Defined Function”.

The locking interface has these characteristics:

The interface provided by the locking service is distinct from that provided by GET_LOCK() and related SQL functions (see Section 12.14, “Locking Functions”). For example, GET_LOCK() does not implement namespaces and provides only exclusive locks, not distinct read and write locks.