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This article mainly explains "how to collect statistical information in MySQL5.5". Interested friends may wish to have a look at it. The method introduced in this paper is simple, fast and practical. Now let the editor take you to learn "how to collect statistics in MySQL5.5"!

For large tables, you need to manually add a scheduled collection task for the ANALYZE TABLE table name.

In MySQL, the query optimizer selects the appropriate execution plan based on statistics.

The main parts of the statistics are as follows:

① cardinality, entries for non-repeating rows in the table

Total number of rows in the ② table

③ index

The data of the table is represented by the primary key index

For the entry of the index, it is represented by the second index

The following action causes InnoDB to randomly sample data pages for each index in the table:

① ANALYZE TABLE statement

② SHOW TABLE STATUS statement

The first access to the table after the ③ database restart

If the innodb_stats_on_metadata parameter is set to ON, the database stores the statistics in the system table

> show global variables like 'innodb_stats_on_metadata'

+-+ +

| | Variable_name | Value |

+-+ +

| | innodb_stats_on_metadata | ON |

+-+ +

1 row in set (0.00 sec)

For null value handling, you can configure it through the innodb_stats_method parameter

> show global variables like 'innodb_stats_method'

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| | Variable_name | Value |

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| | innodb_stats_method | nulls_equal |

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1 row in set (0.00 sec)

Other statistical information can be obtained from the tables under INFORMATION_SCHEMA and PERFORMANCE_SCHEMA libraries.

In order to provide sampling accuracy when collecting statistics, you can adjust the innodb_stats_sample_pages parameter

The default value of this parameter is 8, which is not enough for large tables and needs to be increased.

> show global variables like 'innodb_stats_sample_pages'

+-+ +

| | Variable_name | Value |

+-+ +

| | innodb_stats_sample_pages | 8 |

+-+ +

1 row in set (0.00 sec)

At this point, I believe you have a deeper understanding of "how to collect statistical information in MySQL5.5". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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