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Today, I will talk to you about what are the relevant state parameters of MySQL handler, which may not be well understood by many people. in order to make you understand better, the editor has summarized the following for you. I hope you can get something according to this article.

The list of Handler parameters is as follows:

Mysql > show global status like 'Handle%'

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| | Variable_name | Value |

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| | Handler_commit | 292547310 | |

| | Handler_delete | 20004688 | |

| | Handler_discover | 0 | |

| | Handler_external_lock | 298778503 | |

| | Handler_mrr_init | 0 | |

| | Handler_prepare | 89764296 | |

| | Handler_read_first | 84936796 | |

| | Handler_read_key | 197690980 | |

| | Handler_read_last | 25 | |

| | Handler_read_next | 449603395282 |

| | Handler_read_prev | 488140 | |

| | Handler_read_rnd | 17904308 | |

| | Handler_read_rnd_next | 2234678057572 | |

| | Handler_rollback | 3965287 | |

| | Handler_savepoint | 2 | |

| | Handler_savepoint_rollback | 566 |

| | Handler_update | 150669454 | |

| | Handler_write | 1392716731 | |

+-+ +

18 rows in set (0.00 sec)

| | Handler_commit | number of statements submitted internally |

| Handler_delete | number of times rows are requested to be deleted from the table.

| Handler_discover | MySQL server can ask NDB CLUSTER storage engine whether it knows a table with a certain name. It's called discovery. Handler_discover indicates the number of times it has been discovered by this method.

| Handler_external_lock | this variable is related to the number of locking operations, mainly at the beginning and end of table access.

| Handler_mrr_init | the number of multiple-range reads implemented by the server using the storage engine itself.

| Handler_prepare | counter used in the preparation phase of the two-phase commit operation.

| Handler_read_first | the number of times the first item in the index is read. If high, it recommends that the server is performing a large number of full index scans; for example, SELECT col1 FROM foo, assume that col1 has an index.

| Handler_read_key | number of requests to read a line according to the key. If high, the query and table are indexed correctly.

| Handler_read_last | number of requests to read the last line according to the key.

| Handler_read_next | number of requests to read the next line in key order. If you use a range constraint or if you perform an index scan to query the index column, this value is increased.

| Handler_read_prev | number of requests to read the previous line in key order. This reading method is mainly used to optimize ORDER BY. DESC .

| Handler_read_rnd | number of requests to read a line according to a fixed position. This value is higher if you are executing a large number of queries and need to sort the results. You may use a large number of queries that require MySQL to scan the entire table or your join does not use the index correctly.

| Handler_read_rnd_next | number of requests to read the next line in the data file. If you are doing a lot of table scans, the value is higher. It usually indicates that your table index is incorrect or that the query you write does not make use of the index.

| | Handler_rollback | number of internal ROLLBACK statements |

| Handler_savepoint | number of requests to place a SavePoint in a storage engine.

| Handler_savepoint_rollback | the number of save points required by a storage engine to be rolled back to.

| Handler_update | number of times a row in the table is requested to be updated.

| Handler_write | number of requests to insert a row into the table.

A high value of Handler_read_rnd_next means that the query runs inefficiently and should be indexed for remediation or optimization. This value means the number of requests to read the next line in the data file. If a large number of table scans are being performed, a high value of Handler_read_rnd_next usually indicates that the table index is incorrect or that the query written does not make effective use of the index.

After reading the above, do you have any further understanding of the relevant state parameters of MySQL handler? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

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