code: protected void updateDataVersion() {
          Connection conn = null;
          try {
              long newVersion = System.currentTimeMillis();
  
              conn = ds.getConnection();
              conn.setAutoCommit(false);
              QueryRunner run = new QueryRunner();
  
              run.update(conn, "DELETE FROM gw_dataversion"); //$NON-NLS-1$
              run.update(conn, "INSERT INTO gw_dataversion (version) VALUES (?)",  //$NON-NLS-1$
                      newVersion);
  
              DbUtils.commitAndClose(conn);
              dataVersion = newVersion;
          } catch (SQLException e) {
              dataVersion = -1;
          }
      }
docs: Stores a "dataversion" record in the ES store.  There is only a single one of these.  The
  return value of the add will include the version number of the entity.  This version
  number is what we use to determine whether our cache is stale.