pentaho/pentaho-kettle · error · KettleException

Trans.Exception.UnableToWriteLogChannelInformationToLogTable

Error message

Trans.Exception.UnableToWriteLogChannelInformationToLogTable

What it means

Thrown by Trans.writeLogChannelInformation() when persisting the channel logging hierarchy (channels for the transformation and its steps) to the configured channel log table fails. The method connects, writes channel records, and calls cleanupLogRecords() to time out stale entries; any Exception in that flow is wrapped in this message.

Solutions

Inspect the cause to find the failing statement (write vs cleanupLogRecords DELETE) and fix that database issue.
Recreate the channel log table from the Log tab DDL so its schema matches the current PDI version.
Grant the log user INSERT and DELETE privileges on the channel log table.
Test the channel log table connection; if the write is transient, retry the transformation.

Example fix

// before: cleanup fails due to missing DELETE privilege
GRANT DELETE ON channel_log TO etl_user;
// after: writeLogChannelInformation() completes including cleanup of timed-out records

Defensive patterns

Strategy: try-catch

Validate before calling

// Ensure channel log table exists and is writable before the transformation runs
Database db = new Database(trans, channelLogTable.getDatabaseMeta());
db.connect();
if (!db.checkTableExists("CHANNEL_LOG")) throw new IllegalStateException("CHANNEL_LOG missing");

Try / catch

try {
  trans.execute(null);
} catch (KettleException e) {
  if (e.getMessage().contains("UnableToWriteLogChannelInformation")) {
    log.warn("Channel metadata logging failed; run continues", e.getCause());
  }
}

Prevention

Keep channel log table schema current with the installed PDI version.
Ensure cleanupLogRecords DELETE privileges for the log user.
Watch for lock contention on channel_log in high-concurrency schedulers.

When it happens

Trigger: writeLogChannelInformation() is invoked (from beginProcessing/endProcessing paths); the DB connect, writeLogRecord, or db.cleanupLogRecords(channelLogTable, getName()) throws; wrapped as KettleException(UnableToWriteLogChannelInformationToLogTable).

Common situations: Channel log table missing or its primary-key columns altered; database credentials invalid; cleanup DELETE blocked by privileges or locks; DB connection dropped before the write.

Related errors

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/a912397b1228a65b. Report an issue: GitHub.

Appendix: source

Thrown at engine/src/main/java/org/pentaho/di/trans/Trans.java:2656

    }
    // end PDI-7070

    try {
      db = new Database( this, channelLogTable.getDatabaseMeta() );
      db.shareVariablesWith( this );
      db.connect();
      db.setCommit( logCommitSize );

      List<LoggingHierarchy> loggingHierarchyList = getLoggingHierarchy();
      for ( LoggingHierarchy loggingHierarchy : loggingHierarchyList ) {
        db.writeLogRecord( channelLogTable, LogStatus.START, loggingHierarchy, null );
      }

      // Also time-out the log records in here...
      //
      db.cleanupLogRecords( channelLogTable, getName() );
    } catch ( Exception e ) {
      throw new KettleException( BaseMessages.getString( PKG,
        "Trans.Exception.UnableToWriteLogChannelInformationToLogTable" ), e );
    } finally {
      disconnectDb( db );
    }
  }

  /**
   * Writes step information to a step logging table (if one has been configured).
   *
   * @throws KettleException if any errors occur during logging
   */
  protected void writeStepLogInformation() throws KettleException {
    Database db = null;
    StepLogTable stepLogTable = getTransMeta().getStepLogTable();
    try {
      db = createDataBase( stepLogTable.getDatabaseMeta() );
      db.shareVariablesWith( this );
      db.connect();

View on GitHub (pinned to f3058517a1)