JS7 - Troubleshooting - Database - Connection to MySQL or MariaDB reports connection reset by peer: socket write error

Observations

When using MySQL or MariaDB databases with JS7, the History Service can report errors similar to the following in the JOC log files:

2026-05-07T12:01:29,266 WARN  history-9-1 c.z.h.p.ProxyConnection
- HikariPool-3 - Connection org.mariadb.jdbc.Connection@117d5f0c
marked as broken because of SQLSTATE(08000), ErrorCode(-1)

java.sql.SQLNonTransientConnectionException: (conn=6729) Socket error

Caused by: java.net.SocketException: Connection reset by peer

The History Service stops processing events and no further history information is written to the database.

Explanations

The root cause of this problem is an excessively large log file created by a job.

The JS7 History Service sends job log data to the MySQL or MariaDB database. If the transmitted data exceeds the database setting `max_allowed_packet`, then the database can close the connection initiated by the History Service.

The error message: Connection reset by peer: socket write error indicates that the database connection was closed while processing oversized job log data. Unlike other database systems that return a regular SQL error, MySQL and MariaDB can close the database connection if transmitted blob/clob data exceeds the configured packet size.

JS7 default settings currently use:

These defaults are suitable for Oracle and SQL Server databases, but they can exceed the practical defaults commonly used by MySQL and MariaDB databases.

A frequent reason for oversized logs is unintended debug logging enabled in jobs.

Resolution

Step 1 — Skip the Offending Event (Immediate Workaround)

The immediate workaround is to increase the “last event id” stored in the database table JOC_VARIABLES.

Updating the stored Event ID allows the History Service to skip the offending events that resulted in oversized packets being sent to the MySQL or MariaDB server.

The corresponding row uses a NAME value similar to: history_<controller_id>

Example: history_controller_b2b


Update the TEXT_VALUE column with a later Event ID and restart the History Service from the JOC Cockpit Dashboard.
It is recommended to start with a small increment, for example by 50 events.

Example:

UPDATE JOC_VARIABLES
SET TEXT_VALUE = '<new_event_id>'
WHERE NAME = 'history_<controller_id>';

If the error persists, then increase the Event ID again by another 50 events and restart the History Service again.
Care should be taken not to skip too many events because this can result in missing history entries and missing job logs.

Step 2 — Increase Database Packet Size

Increase the MySQL or MariaDB setting: max_allowed_packet

Example configuration:

[mysqld]
max_allowed_packet=50M

Depending on the environment and expected log volume, larger values can be used.

After changing the setting, restart the MySQL or MariaDB service.

Step 3 — Reduce JS7 Log Size Limits

Future JS7 releases will reduce the default values for acceptable job log sizes processed by the History Service to 50 MB 

Feature Status:

FEATURE AVAILABILITY STARTING FROM RELEASE 2.8.4

JOC-2225 - Getting issue details... STATUS

Current defaults:

Recommended values for MySQL/MariaDB environments:

This recommendation matches the practical defaults commonly used by MySQL and MariaDB databases and provides safer cross-database compatibility. Jobs that legitimately require larger logs will require these settings to be adjusted accordingly.