node.js - Socket descriptors keep on increasing when callback is called from error block

Question

I am executing following code

var pg = require('pg').native;

async.waterfall([
      function (callback) {
          //some code
      },
      function (result,callback) {
          logger.debug('Async waterfall 2: Querying events.');
          try {
              callingFirstEvent(queryMode, request, foundEvents, callback);
          } catch(ex) {
              logger.error('callingFirstEvent::Error occurred in async waterfall 2: ' + ex.message);
          }
      },
      function (result, callback) {
          //some code
      },
      ], 
      function (err, res) {
      //some code
  }
  );


var callingFirstEvent = function (queryMode, request, foundEvents, callback) {
    var conStringList = queryMode.conStringList;
    var executeQuery = function (conString, limit, next) {
    pg.connect(conString, function(err, client, done) {
      //below error code is reason of increased socket descriptors
      if (err) {  
        logger.error('callingFirstEvent : Cannot fetch a client from pool', err);
        next(null, limit); 
        return;
      }

      client.query(sql, function (err, result) {
        done();
        if (err) {
          logger.error('callingFirstEvent', err);
          logger.error('sql:' + sql);
          next(err, limit);
          return;
        }
        //some code
      }); // client.query
    }); // pg.connect
  }; // executeQuery

  var schedule = [];
  conStringList.forEach(function (conString, index) {
    if (index == 0) {
      schedule.push(async.apply(executeQuery, conString, request.query.max));
    } 
  });
};

When callingFirstEvent function is called from waterfall model and if it stuck in error block of callingFirstEvent

 if (err) {
        logger.error('callingFirstEvent : Cannot fetch a client from pool', err);
        next(null, limit);
        return;
      }

socket descriptors increased.

Here is how I am checking for total number of socket descriptors

ls -ltr /proc/cat /path of pid/fd/ | grep socket | wc -l

How to close socket descriptors after they are opened? or is there any way not to open these sockets?

Answer 1

You are leaking sockets. Most errors, in fact all errors except read timeouts, are fatal to the socket and should cause you to close the socket.