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This article mainly introduces the logical analysis of the statistical data collection of data volume change in Mysql 5.7, which has a certain reference value, and interested friends can refer to it. I hope you will gain a lot after reading this article.

1. Persistence (PERSISTENT) and non-persistence statistics (TRANSIENT)

Mysql statistics are divided into persistence and non-persistence.

Persistent statistics are stored in mysql.innodb_index_stats and mysql.innodb_table_stats

Non-persistent statistics are stored in information_schema.indexes and information_schema.tables

The former is the innodb table and the latter is the memory table. They are controlled by the parameter innodb_stats_persistent, which defaults to ON.

Second, the way to change the persistent statistics.

When I look at the change logic, I find that non-persistent statistics are updated directly or synchronously. But persistent statistics should be updated asynchronously and appear to be a typical producer-consumer model. There is a special background thread in Mysql to collect statistics as follows:

Mysql > select name,thread_id from performance_schema.threads where NAME like'% dict_stats_thread%'\ gateway * 1. Row * * name: thread/innodb/dict_stats_threadthread_id: 25 Thank you for reading this article carefully I hope the article "logical Analysis of Statistical data Collection of data Volume change in Mysql 5.7" shared by the editor will be helpful to everyone. At the same time, I also hope that you will support and pay attention to the industry information channel, and more related knowledge is waiting for you to learn!

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