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How to delete a large number of rows in MySQL?
Convert the list to an sql delete command. This results in a single delete command with a list of 100000 rows. Run each file through MySQL and rename the file. This allows to stop the script and continue where we left of.
How does an InnoDB row delete work in MySQL?
An InnoDB row delete first goes into the “Change buffer”; this actually delays the work to do the delete. When the delete happens, removes the one row from the one block it is in, then considers merging the block with its neighbor.
When to use delete instead of update in MySQL?
When you create a fixed width column and update that instead of deleting, there’s no need for physical reordering across your huge table because the space consumed by a row and table itself is constant. During off hours, a single DELETE can be used to remove the unnecessary rows.
How can I improve MySQL delete from large performance?
If that’s not enough states, you could use TINYINT with 256 possible values. Adding this new column will probably take a long time, but once it’s over, your updates should be much faster as long as you do it off the PRIMARY as you do with your deletes and don’t index this new column.
Is there way to prevent delete s in MySQL?
Preventing DELETE s is something you want in such cases. Or, even better, change the foreign key once, so it does the deletion automatically (cascading): To expand on the accepted answer, you have to specify the constraint name after DROP FOREIGN KEY
Why does MySQL pause after deleting a file?
Run each file through MySQL and rename the file. This allows to stop the script and continue where we left of. To let the server breath and allow other queries to perform without too much interference, we pause 30s after each delete, and pause 15 minutes every 20 command.
Is it possible to delete millions of rows in RDS?
Running on RDS, SELECT INTO OUTFILE is not an option. The easiest would be to run a single delete query, but with several millions of rows concerned and the lack of index on created_at, this would put the server on fire. Adding an index on created_at and status is too time consuming and would lock the table for too long.