The number of digest instances that could not be instrumented in the events_statements_summary_by_digest  table. This can be nonzero if the value of performance_schema_digests_size  is too small. 

• Performance_schema_file_classes_lost 

How many file instruments could not be loaded. 

• Performance_schema_file_handles_lost 

How many file instrument instances could not be opened. 

• Performance_schema_file_instances_lost 

How many file instrument instances could not be created. 

• Performance_schema_hosts_lost 

The number of times a row could not be added to the hosts  table because it was full. 

• Performance_schema_index_stat_lost 

The number of indexes for which statistics were lost. This can be nonzero if the value of performance_schema_max_index_stat  is too small. 

• Performance_schema_locker_lost 

How many events are “lost”  or not recorded, due to the following conditions: 

•Events are recursive (for example, waiting for A caused a wait on B, which caused a wait on C). 

•The depth of the nested events stack is greater than the limit imposed by the implementation. 

Events recorded by the Performance Schema are not recursive, so this variable should always be 0. 

• Performance_schema_memory_classes_lost 

The number of times a memory instrument could not be loaded. 

• Performance_schema_metadata_lock_lost 

The number of metadata locks that could not be instrumented in the metadata_locks  table. This can be nonzero if the value of performance_schema_max_metadata_locks  is too small. 

• Performance_schema_mutex_classes_lost 

How many mutex instruments could not be loaded. 

• Performance_schema_mutex_instances_lost 

How many mutex instrument instances could not be created. 

• Performance_schema_nested_statement_lost 

The number of stored program statements for which statistics were lost. This can be nonzero if the value of performance_schema_max_statement_stack  is too small. 

• Performance_schema_prepared_statements_lost 

