Set application_name to 'pgloader' by default.

It's always been possible to set application_name to anything really,
making it easier to follow the PostgreSQL queries made by pgloader.
Force that setting to 'pgloader' by default.

Fix #387.

src/pgsql/queries.lisp

@@ -324,15 +324,25 @@ select i.relname,
 
 (defun sanitize-user-gucs (gucs)
   "Forbid certain actions such as setting a client_encoding different from utf8."
-  (append
-   (list (cons "client_encoding" "utf8"))
-   (loop :for (name . value) :in gucs
-      :when    (and (string-equal name "client_encoding")
-                    (not (member value '("utf-8" "utf8") :test #'string-equal)))
-      :do      (log-message :warning
-                            "pgloader always talk to PostgreSQL in utf-8, client_encoding has been forced to 'utf8'.")
-      :else
-      :collect (cons name value))))
+  (let ((gucs
+         (append
+          (list (cons "client_encoding" "utf8"))
+          (loop :for (name . value) :in gucs
+             :when    (and (string-equal name "client_encoding")
+                           (not (member value '("utf-8" "utf8") :test #'string-equal)))
+             :do      (log-message :warning
+                                   "pgloader always talk to PostgreSQL in utf-8, client_encoding has been forced to 'utf8'.")
+             :else
+             :collect (cons name value)))))
+    ;;
+    ;; Now see about the application_name, provide "pgloader" if it's not
+    ;; been overloaded already.
+    ;;
+    (cond ((not (assoc "application_name" gucs :test #'string-equal))
+           (append gucs (list (cons "application_name" "pgloader"))))
+
+          (t
+           gucs))))
 
 (defun list-reserved-keywords (pgconn)
   "Connect to PostgreSQL DBNAME and fetch reserved keywords."

test/csv-hstore.load

@@ -8,7 +8,8 @@ LOAD CSV
           fields escaped by backslash-quote
 
       SET work_mem to '128MB',
-          standard_conforming_strings to 'on'
+          standard_conforming_strings to 'on',
+          application_name to 'my app name'
 
    BEFORE LOAD DO
     $$ create extension if not exists hstore; $$,