How can I speed up MySQL delete?

How can I speed up MySQL delete?

3 Answers

1. do the same as SELECT – found rows.
2. log operation (write into redo-log files)
3. mark rows as deleted.
4. lock deleted rows – wait if any other operations use them.
5. update indexes.

How long does SQL delete take?

A regular delete was by far and away the slowest operation. When deleting 90% of the data it took 11 seconds on average. It only bested any DDL methods when removing as little as 10% of the rows.

Are delete queries slow?

Right now deletion speed is between 1-10k per minute, it is very slow for us.

How does delete work in MySQL?

Explanation:

1. The DELETE statement deletes rows from table_name and returns the number of deleted rows.
2. The conditions in the WHERE clause (optional) identify which rows to delete.
3. Without WHERE clause, all rows are deleted.
4. If you specify the ORDER BY clause, the rows are deleted in specified order.

Why delete is slow?

Things that can cause a delete to be slow: cascade delete (those ten parent records you are deleting could mean millions of child records getting deleted) Transaction log needing to grow. Many Foreign keys to check.

What is delete query in MySQL?

What is the DELETE Query? MySQL Delete command is used to delete rows that are no longer required from the database tables. It deletes the whole row from the table and returns count of deleted rows. The Delete query in MySQL can delete more than one row from a table in a single query.

What MySQL delete return?

Single-Table Syntax. The DELETE statement deletes rows from tbl_name and returns the number of deleted rows.

How long does it take to delete a mySQL table?

MySQL delete is very slow and takes long time! I recently had an issue with mysql database and the database has grown too large about 200k records and i was needing to delete all junk and needless data of approx 50k rows in my table.

When to delete rows in MySQL with InnoDB?

With InnoDB, deleted rows must be held in case there is a crash or other reason to rollback the action. This is costly, and may get more costly with larger counts, as you are seeing. Plan A: Delete in smaller chunks and COMMIT after each chunk. (Similarly, chunking should be applied to Updates.)

What’s the best way to delete a table in PHP?

You can write a php script running as cron which execute delete when the server is idle. Keep in mind that running DELETE will LOCK your tables. So perform this operation only when the server is idle. So whats the solution? The only way you can clean up your table is using the following methods. 1.