Error message: Index columns size too large...

Problem

The message appears in the dashboard for the "Jobs" database table:

Index column size too large. The maximum column size is 767 bytes.

Cause

The database software used (MySQL or MariaDB) is outdated.

Due to the utf8mb4 encoding, the maximum permitted index size of 767 bytes is exceeded. As each character in utf8mb4 requires four bytes and the index should comprise up to 255 characters, this results in a total size of 1,020 bytes (255 characters × 4 bytes = 1,020 bytes).

Solution

Your database software needs to be updated. Please contact your web host or your server administrator. In current versions, the available index size is 3,072 bytes.