Why Does My MySQL Autoincrement Column Skip Numbers and Jump by 10?

Why Does MySQL Autoincrement Column Jump by 10?

In MySQL, an autoincrement column is a column whose value is automatically incremented by a specified interval with each new insertion. Typically, this interval is 1. However, under certain circumstances, you may notice that the autoincrement value skips increments of 9, resulting in a jump by 10.

The Reason:

This behavior is a result of a configuration used by ClearDB, a managed MySQL service. To ensure that multiple master databases do not generate duplicate autoincrement values, ClearDB uses circular replication and configures MySQL to skip certain keys. Specifically, autoincrement values are incremented by 10 to avoid any potential key conflicts.

Is It a Problem?

While the autoincrement value jumping by 10 is unexpected, it is not generally considered a problem. Most applications do not rely heavily on the precise autoincrement value itself, but rather on the unique and increasing nature of the value. Skipping increments will not affect the uniqueness or integrity of the autogenerated keys.

Additional Information:

It's important to note that this behavior is specific to ClearDB, and other MySQL environments may not exhibit it. Additionally, the autoincrement_increment value should not be modified to correct this behavior, as this can lead to serious issues. ClearDB's configuration is specifically designed to prevent conflicts, and any changes could compromise the system's reliability.

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