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Measures reported by MySQLCluLocTest
The locking activity of a database server must be monitored carefully because an application holding a specific lock for a long time could cause a number of other transactions relying on the same lock to fail. The MySQLCluLocTest monitors the locking activity of various transactions supported by each node on the target MySQL Cluster database server.
Outputs of the test : One set of results for each node in the MySQL cluster database server being monitored
The measures made by this test are as follows:
| Measurement |
Description |
Measurement Unit |
Interpretation |
| Pct_lock_waits |
Indicates the percentage of lock requests that could not be satisfied immediately and hence, required the caller to wait before being granted the lock. |
Percent |
A value close to 100 for this measure can have an adverse impact on application performance. Possible reasons for this behavior could be:
inadequate number of locks available in the database, unusually high locking behavior of applications accessing the database, improper database application design, etc. |
| Table_locks_waited |
Indicates the number of times in the last measurement period a table lock could not be acquired immediately and a wait was needed. |
Number |
If the number of waits is high, application performance could suffer. You should first optimize your queries, and then either split your table(s) or use replication. |
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