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This article introduces the relevant knowledge of "what are the characteristics of the InnoDB engine in mysql". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

1. Insert cache to improve insert performance.

Insertbuffer is an enhanced version of insertbuffer, insertbuffer is only valid for inserts, and changebuffer is valid for insert/update/delete. The insert cache is valid only for non-unique and secondary indexes. Each insert is not written on the index page, but first determines whether the inserted nonclustered index page is in the cache. If so, insert it directly. If it does not exist, insert insertbuffer, merge at a certain frequency, and write back to disk.

2. Write twice to ensure the reliability of data pages operated by InnoDB storage engine.

The Double write is divided into two parts, one is the in-memory double write buffer with the size of 2MB, and the other is the continuous 128data pages in the shared table space on the physical disk, that is, the size of the two regions (also 2MB).

3. Adaptive hash index, hash is equivalent query.

The InnoDB storage engine monitors queries for each index page on the table. If it is observed that building an hash index will lead to a speed increase, then building the corresponding index is called an adaptive hash index.

4. Asynchronous IO to improve disk operation performance.

The current database system generally uses asynchronous IO to handle disk operations, and so is the InnoDB storage engine. The advantage of AIO is that it reduces the time required for SQL query.

5. Refresh adjacency pages

When a dirty page is refreshed, the InnoDB storage engine detects whether there are other dirty pages in the area, and if so, refreshes it together.

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