Home/ Questions/Q 7668563
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-31T15:23:43+00:00

I have a table in my database with around 5m records, and I’m noticing

  • 0

I have a table in my database with around 5m records, and I’m noticing the IDs of the each records are not incrementing by one any every insert.

For example, I have the following schema setup:

my_table
activity_id INT(11) PRIMARY (AUTO_INCREMENT), created_at DATETIME

If I look at the table and sort by the DATE TIME, the numbers are not sequential. It actually seems like MySQL is looking for when there is a deletion and then add the new record in there.

Edit    Delete  5000089     2012-03-17 04:31:46
Edit    Delete  5000087     2012-03-17 04:31:44
Edit    Delete  5000086     2012-03-17 04:31:43
Edit    Delete  5000085     2012-03-17 04:31:43
Edit    Delete  5000084     2012-03-17 04:31:31
**Edit  Delete  5000088     2012-03-17 04:31:30**
**Edit  Delete  5000076     2012-03-17 04:31:30**
Edit    Delete  5000082     2012-03-17 04:31:29

As you can see by the info about, at 4:31:30 GMT, we had 2 inserts, where it should have 83, and 84 but its incrementing weirdly. The database insert from the application does not specify the ID and the field of activity_id is set to Auto_increment.

Any help would be greatly appertained why this happening.

Has anyone see anything like this before?

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    The auto-increment documentation has this paragraph:

    In this case (when the AUTO_INCREMENT column is part of a
    multiple-column index), AUTO_INCREMENT values are reused if you delete
    the row with the biggest AUTO_INCREMENT value in any group. This
    happens even for MyISAM tables, for which AUTO_INCREMENT values
    normally are not reused.

    It seems to imply that index values are reused with InnoDB tables, and in certain cases in MyISAM tables. So, if you delete a row, there’s a chance MySQL will create a new row with the old row’s ID.

    • 0