improving error event listeners.

lib/connect.js

@@ -20,6 +20,7 @@ function poolConnect(ctx, config) {
                 if (isFresh) {
                     $npm.utils.addReadProp(client, '$used', true, true);
                 }
+                setCtx(client, ctx);
                 var end = lockClientEnd(client);
                 resolve({
                     isFresh: isFresh,
@@ -47,6 +48,7 @@ function directConnect(ctx, config) {
                 });
                 reject(err);
             } else {
+                setCtx(client, ctx);
                 var end = lockClientEnd(client);
                 resolve({
                     isFresh: true,
@@ -70,12 +72,20 @@ function lockClientEnd(client) {
         // 1. the client made the call directly, against the library's documentation (invalid code)
         // 2. connection with the server broke while under heavy communications, and the connection
         //    pool is trying to terminate all clients forcefully.
-        $npm.con.error("Abnormal client.end() call, due to invalid code or failed server connection.\n%s\n", $npm.utils.getLocalStack(3));
+        $npm.con.error("Abnormal client.end() call, due to invalid code or failed server connection.\n%s\n",
+            $npm.utils.getLocalStack(3));
         end.call(client);
     };
     return end;
 }
 
+function setCtx(client, ctx) {
+    Object.defineProperty(client, '$ctx', {
+        value: ctx,
+        writable: true
+    });
+}
+
 module.exports = function (config) {
     return {
         pool: function (ctx) {

lib/database.js

@@ -25,24 +25,13 @@ var $arr = require('./array');
  *
  * For any given connection, you should only create a single {@link Database} object in a separate module,
  * to be shared in your application (see the code example below). If instead you keep creating the {@link Database}
- * object dynamically, your application will suffer from loss in performance and memory leaks because of event
- * handlers that each {@link Database} object needs to set up.
+ * object dynamically, your application will suffer from loss in performance, and will be getting a warning in a
+ * development environment (when `NODE_ENV` = `development`):
  *
- * **Starting with v.4.7.0:**
+ * `WARNING: Creating a duplicate database object for the same connection.`
  *
- * If you create more than one {@link Database} object for the same connection, you will see the following warning
- * in a development environment (when `NODE_ENV` = `development`):
- *
- * `WARNING: Creating a duplicate database object for the same connection`.
- *
- * And since every {@link Database} object needs to set up its own event listeners, you are likely to see the following
- * warning in the console also:
- *
- * `Warning: Possible EventEmitter memory leak detected. 11 error listeners added. Use emitter.setMaxListeners() to increase limit`.
- *
- * If you ever see any of those warnings, do not try increasing the limit, this won't help you.
- * Instead, rectify your {@link Database} object initialization, so there is only one object per connection details.
- * See the example provided below.
+ * If you ever see this warning, rectify your {@link Database} object initialization, so there is only one object
+ * per connection details. See the example provided below.
  *
  * See also: property `noWarnings` in {@link module:pg-promise Initialization Options}.
  *
@@ -105,7 +94,7 @@ var $arr = require('./array');
 function Database(cn, dc, config) {
 
     checkForDuplicates(cn, config);
-    setErrorHandler(cn, dc, config);
+    setErrorHandler(config);
 
     var $p = config.promise;
 
@@ -1209,7 +1198,7 @@ function Database(cn, dc, config) {
 
 }
 
-var dbObjects = {};
+var jsHandled, nativeHandled, dbObjects = {};
 
 function checkForDuplicates(cn, config) {
     var cnKey = JSON.stringify(cn);
@@ -1223,15 +1212,30 @@ function checkForDuplicates(cn, config) {
     }
 }
 
-function setErrorHandler(cn, dc, config) {
-    // this event only happens when the connection is lost physically,
-    // which cannot be tested automatically; removing from coverage:
-    // istanbul ignore next
-    config.pgp.pg.on('error', function (err) {
-        $npm.events.error(config.options, err, {
-            cn: $npm.utils.getSafeConnection(cn),
-            dc: dc
-        });
+function setErrorHandler(config) {
+    // we do not do code coverage specific to Native Bindings:
+    // istanbul ignore if
+    if (config.options.pgNative) {
+        if (!nativeHandled) {
+            config.pgp.pg.on('error', onError);
+            nativeHandled = true;
+        }
+    } else {
+        if (!jsHandled) {
+            config.pgp.pg.on('error', onError);
+            jsHandled = true;
+        }
+    }
+}
+
+// this event only happens when the connection is lost physically,
+// which cannot be tested automatically; removing from coverage:
+// istanbul ignore next
+function onError(err, client) {
+    var ctx = client.$ctx;
+    $npm.events.error(ctx.options, err, {
+        cn: $npm.utils.getSafeConnection(ctx.cn),
+        dc: ctx.dc
     });
 }
 

lib/formatting.js

@@ -638,7 +638,7 @@ var $as = {
      * or property name that's missing within the formatting parameters.
      *
      * It can also be set to a function, to be called with two parameters that depend on the type of formatting being used,
-     * and to return the actual value:
+     * and to return the actual default value:
      *
      * - Named Parameters formatting:
      *   - `name` - name of the property missing in the formatting object

package.json

@@ -1,6 +1,6 @@
 {
   "name": "pg-promise",
-  "version": "5.0.5",
+  "version": "5.1.0",
   "description": "Promises interface for PostgreSQL",
   "main": "lib/index.js",
   "scripts": {