Method execute

src/tsd/QueryExecutor.java:224–475

Execute the RPC and serialize the response @param query The HTTP query to parse and and return results to

(final HttpQuery query)

   * @param query The HTTP query to parse and and return results to
   */
  public void execute(final HttpQuery query) {
    http_query = query;
    final QueryStats query_stats = 
        new QueryStats(query.getRemoteAddress(), ts_query, query.getHeaders());
    ts_query.setQueryStats(query_stats);
    
    /**
     * Sends the serialized results to the caller. This should be the very
     * last callback executed.
     */
    class CompleteCB implements Callback<Object, ChannelBuffer> {
      @Override
      public Object call(final ChannelBuffer cb) throws Exception {
        query.sendReply(cb);
        return null;
      }
    }
    
    /**
     * After all of the queries have run and we have data (or not) then we
     * need to compile the iterators.
     * This class could probably be improved:
     * First we iterate over the results AND for each result, iterate over
     * the expressions, giving a time synced iterator to each expression that 
     * needs the result set.
     * THEN we iterate over the expressions again and build a DAG to determine
     * if any of the expressions require the output of an expression. If so
     * then we add the expressions to the proper parent and compile them in
     * order.
     * After all of that we're ready to start serializing and iterating
     * over the results.
     */
    class QueriesCB implements Callback<Object, ArrayList<DataPoints[]>> {
      public Object call(final ArrayList<DataPoints[]> query_results) 
        throws Exception {
        
        for (int i = 0; i < query_results.size(); i++) {
          final TSSubQuery sub = ts_query.getQueries().get(i);
          
          Iterator<Entry<String, TSSubQuery>> it = sub_queries.entrySet().iterator();
          while (it.hasNext()) {
            final Entry<String, TSSubQuery> entry = it.next();
            if (entry.getValue().equals(sub)) {
              sub_query_results.put(entry.getKey(), query_results.get(i));
              if (expressions != null) {
                for (final ExpressionIterator ei : expressions.values()) {
                  if (ei.getVariableNames().contains(entry.getKey())) {
                    final TimeSyncedIterator tsi = new TimeSyncedIterator(
                            entry.getKey(), sub.getFilterTagKs(),
                            query_results.get(i));
                    final NumericFillPolicy fill = fills.get(entry.getKey());
                    if (fill != null) {
                      tsi.setFillPolicy(fill);
                    }
                    ei.addResults(entry.getKey(), tsi);
                    if (LOG.isDebugEnabled()) {
                      LOG.debug("Added results for " + entry.getKey() +
                              " to " + ei.getId());