Enterprise Manager
Lists the Handler Activity metrics and provides a brief description of each.
Table 6.8 Handler Activity Metrics
| Name | Description |
|---|---|
| Commit (Delta) | The number of internal COMMIT statements. |
| Delete (Delta) | The number of times that rows have been deleted from tables. |
| Discover (Delta) | A counter for the prepare phase of two-phase commit operations. |
| External Lock (Delta) | The server increments this variable for each call to its external_lock() function, which generally occurs at the beginning and end of access to a table instance. |
| Mrr Init (Delta) | The number of times the server uses a storage engine's own Multi-Range Read implementation for table access. |
| Prepare (Delta) | The number of times the first entry in an index was read. |
| Read First (Delta) | The number of requests to read a row based on a index key value. If this value is high, it suggests that the server is doing a lot of full index scans. |
| Read Key (Delta) | The number of requests to read the last key in an index. If this value is high, it is a good indication that your tables are properly indexed for your queries. |
| Read Last (Delta) | The number of requests to read the last key in an index. |
| Read Next (Delta) | The number of requests to read the next row in key order. This value is incremented if you are querying an index column with a range constraint or if you are doing an index scan. |
| Read Prev (Delta) | The number of requests to read the previous row in key order. This read method is mainly used to optimize ORDER BY ... DESC. |
| Read Rnd (Delta) | The number of requests to read a row based on a fixed position. This value is high if you are doing a lot of queries that require sorting of the result. |
| Read Rnd Next (Delta) | The number of requests to read the next row in the data file. This value is high if you are doing a lot of table scans. |
| Rollback (Delta) | The number of requests for a storage engine to perform a rollback operation. |
| Savepoint (Delta) | The number of requests for a storage engine to place a savepoint. |
| Savepoint Rollback (Delta) | The number of requests for a storage engine to rollback to a savepoint. |
| Update (Delta) | The number of requests to update a row in a table. |
| Write (Delta) | The number of requests to insert a row in a table. |
| Indexes Not Being Used Efficiently (Rate) | The target server does not appear to be using indexes efficiently. The values of Handler_read_rnd_next and Handler_read_rnd together - which reflect the number of rows read via full table scans - are high compared to the Handler variables which denote index accesses - such as Handler_read_key, Handler_read_next etc. Examine your tables and queries for proper use of indexes. |
| Rows Read Via Indexes (Delta) | Rows read via the storage engine handler layer that used indexes in the last interval. |
| Rows Read Via Indexes (Per Sec Avg) | Average of rows read per second via the storage engine handler layer that used indexes in the last interval. |
| Rows Read Via Scan (Delta) | Rows read via the storage engine handler layer that used a table scan in the last interval. |
| Rows Read Via Scan (Per Sec Avg) | Average of rows read per second via the storage engine handler layer that used a table scan. |
| Index Usage Ratio (Delta) | The ratio of rows read via indexes vs rows read via table scan in the last interval. |