code: @Override
  	public void onTxCommit(Transaction tx) {
  		if (!tx.isReadOnly() && enableLogging) {
  			LogSeqNum lsn = new CommitRecord(txNum).writeToLog();
  			VanillaDb.logMgr().flush(lsn);
  		}
  	}
docs: Writes a commit record to the log, and then flushes the log record to
  disk.
  
  @param tx
  the context of committing transaction