How to enable WAL journaling?

[johanneswk]

I have found the following code in class-wp-sqlite-translator:

$valid_journal_modes = array( 'DELETE', 'TRUNCATE', 'PERSIST', 'MEMORY', 'WAL', 'OFF' ); if ( defined( 'SQLITE_JOURNAL_MODE' ) && in_array( SQLITE_JOURNAL_MODE, $valid_journal_modes, true ) ) { $this->pdo->query( 'PRAGMA journal_mode = ' . SQLITE_JOURNAL_MODE ); }

Where can I set this variable to SQLITE_JOURNAL_MODE = WAL? Is there a file for these variables?