The percentage of number of waits to gain a lock on the MyISAM table versus the number of locks requested. MySQL uses table-level locking for MyISAM, MEMORY, and MERGE tables. The monitor threshold is analyzed against an average of values returned in polls to the agent where the Number of Samples parameter controls the number of samples included in the calculation of the average.
An unhealthy state indicates the percentage of table cache hit rate is low. The table cache might not have enough storage to hold tables open. Additionally, an excessive amount of concurrent connections can cause rapid decrease in table cache storage.
To address low table hit percent increase the table_cache size to allow additional tables to be stored.