Insufficient max_allowed_packet Size

Last updated on Jun 12, 2023
Applies To MySQL Source (all variants) with BinLog Pipeline mode.
Error Message Text(s) Increase max_allowed_packet_size or slave_max_allowed_packet on the master!

Potential Causes

  • If a packet larger than the max_allowed_packet size is received by the MySQL server, it is not written, and the associated Events are stored as Failed Events in the BinLog. When Hevo tries to read these failed Events, it encounters this error.

Suggested Actions

  • In the MySQL server, the max_allowed_packet sets an upper limit on the packet size that can be written to the master database. You must set this system variable to more than the size of the largest packet you anticipate.

    To specify the max_allowed_packet size:

    1. Navigate to your MySQL Server install directory.

    2. Open the config file:
      • my.ini in the case of Windows.
      • my.cnf in the case of Linux.
    3. Search for the max_allowed_packet parameter in the file or add it if it does not exist.

    4. Set the required packet size:

      max_allowed_packet= <required_size>

      For example, to set the value to 1 gigabyte, use one of the following:

      max_allowed_packet = 1073741824
      max_allowed_packet = 1G
    5. Restart your MySQL server for the changes to take effect.

Note: The system variable, slave_max_allowed_packet only determines the largest packet size that a slave can read from a master. Hence, modifying this value does not resolve the error.

See Also

Revision History

Refer to the following table for the list of key updates made to this page:

Date Release Description of Change
Sep-05-2022 NA Brought this page under its respective Source documentation folder.
Sep-09-2021 1.71 New document.

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