where table_schema='performance_schema' and table_name='metadata_locks';
column_name column_comment
OBJECT_TYPE Object type. One of BACKUP, COMMIT, EVENT, FUNCTION, GLOBAL, LOCKING SERVICE, PROCEDURE, SCHEMA, TABLE, TABLESPACE, TRIGGER (unused) or USER LEVEL LOCK.
OBJECT_SCHEMA Object schema.
OBJECT_NAME Object name.
OBJECT_INSTANCE_BEGIN Address in memory of the instrumented object.
LOCK_TYPE Lock type. One of BACKUP_FTWRL1, BACKUP_START, BACKUP_TRANS_DML, EXCLUSIVE, INTENTION_EXCLUSIVE, SHARED, SHARED_HIGH_PRIO, SHARED_NO_READ_WRITE, SHARED_NO_WRITE, SHARED_READ, SHARED_UPGRADABLE or SHARED_WRITE.
LOCK_DURATION Lock duration. One of EXPLICIT (locks released by explicit action, for example a global lock acquired with FLUSH TABLES WITH READ LOCK) , STATEMENT (locks implicitly released at statement end) or TRANSACTION (locks implicitly released at transaction end).
LOCK_STATUS Lock status. One of GRANTED, KILLED, PENDING, POST_RELEASE_NOTIFY, PRE_ACQUIRE_NOTIFY, TIMEOUT or VICTIM.
SOURCE Source file containing the instrumented code that produced the event, as well as the line number where the instrumentation occurred. This allows one to examine the source code involved.