Preparations

1. go to Admin Console
2. go to Configuration → Website → Advanced section
3. if "Track database changes to change log" setting is disabled, then enable it and logout

Part 1

• in IDE:
  1. open "core/kernel/db/db_event_handler.php" file for editing
  2. locate "\kDBEventHandler::_update" method
  3. change "if ( $object->Update($id) ) {" line into "if ( $object->Update($id, array('l1_Translation', 'LastChanged', 'LastChangeIP')) ) {"
  4. save changes
• in Admin Console:
  1. go to Website & Content → Labels & Phrases section
  2. open any record for editing
  3. change "Label" and "Phrase" fields
  4. save changes
  5. go to Logs & Reports → Changes Log section
  6. open record, that was just added
  7. confirm, that only changes to l1_Translation' and 'LastChanged' (optionally 'LastChangeIP') fields are shown there, because only they were saved into the database (only lines having "=>" represent a changed field value)

Part 2

• in IDE:
  1. open "core/kernel/db/db_event_handler.php" file for editing
  2. rollback any changes to "\kDBEventHandler::_update" method made before
  3. save changes
• in Admin Console:
  1. go to Website & Content → Labels & Phrases section
  2. open any record for editing
  3. change "Label" and "Phrase" fields
  4. save changes
  5. go to Logs & Reports → Changes Log section
  6. open record, that was just added
  7. confirm, that only changes to 'Phrase', 'PhraseKey', l1_Translation' and 'LastChanged' (optionally 'LastChangeIP') fields are shown there, because they were saved into the database

Part 3

• in Admin Console:
  1. go to Website & Content → Labels & Phrases section
  2. add new record
  3. confirm, that record was added correctly and that action present in Changes Log
  4. delete added record
  5. confirm, that record was deleted correctly and that action present in Changes Log