Performance Schema rwlock_instances Table
The rwlock_instances table lists all read write lock (rwlock) instances that the Performance Schema sees while the server is executing. A read write is a mechanism for ensuring threads can either share access to common resources, or have exclusive access.
The performance_schema_max_rwlock_instances system variable specifies the maximum number of instrumented rwlock objects.
The rwlock_instances table contains the following columns:
| Column | Description |
|---|---|
NAME | Instrument name associated with the read write lock |
OBJECT_INSTANCE_BEGIN | Address in memory of the instrumented lock |
WRITE_LOCKED_BY_THREAD_ID | THREAD_ID of the locking thread if locked in write (exclusive) mode, otherwise NULL. |
READ_LOCKED_BY_COUNT | Count of current read locks held |
Content reproduced on this site is the property of its respective owners,
and this content is not reviewed in advance by MariaDB. The views, information and opinions
expressed by this content do not necessarily represent those of MariaDB or any other party.
