diff --git a/CHANGELOG.md b/CHANGELOG.md
index 89cf42b..9ccc729 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,8 @@ The following changes have been committed to the **master** branch since the 1.0
 
 * Add PostgreSQL streaming option information to **Tips & Tricks**.
 * Minor documentation fixes.
+* Improve `Unknown dbtype` exception message (to clarify that `:classname` is also missing).
+* Address #89, #91 by making minor performance tweaks to `next.jdbc.result-set` functions.
 * Planning to move to MAJOR.MINOR.COMMITS versioning scheme (1.0.375).
 
 ## Stable Builds
diff --git a/src/next/jdbc/connection.clj b/src/next/jdbc/connection.clj
index 78d40ed..bda4787 100644
--- a/src/next/jdbc/connection.clj
+++ b/src/next/jdbc/connection.clj
@@ -198,7 +198,9 @@
                                 (recur more)
                                 (throw loaded))
                               loaded)))))))
-          (throw (ex-info (str "Unknown dbtype: " dbtype) db-spec)))
+          (throw (ex-info (str "Unknown dbtype: " dbtype
+                               ", and :classname not provided.")
+                          db-spec)))
         [url etc]))))
 
 (defn ->pool
diff --git a/src/next/jdbc/result_set.clj b/src/next/jdbc/result_set.clj
index 6bf8f39..296d51b 100644
--- a/src/next/jdbc/result_set.clj
+++ b/src/next/jdbc/result_set.clj
@@ -45,14 +45,16 @@
 
   Requires both the `:qualifier-fn` and `:label-fn` options."
   [^ResultSetMetaData rsmeta opts]
-  (assert (:qualifier-fn opts) ":qualifier-fn is required")
-  (assert (:label-fn opts) ":label-fn is required")
-  (mapv (fn [^Integer i] (keyword (some-> (.getTableName rsmeta i)
-                                          (not-empty)
-                                          ((:qualifier-fn opts)))
-                                  (-> (.getColumnLabel rsmeta i)
-                                      ((:label-fn opts)))))
-        (range 1 (inc (.getColumnCount rsmeta)))))
+  (let [qf (:qualifier-fn opts)
+        lf (:label-fn opts)]
+    (assert qf ":qualifier-fn is required")
+    (assert lf ":label-fn is required")
+    (mapv (fn [^Integer i] (keyword (some-> (.getTableName rsmeta i)
+                                            (not-empty)
+                                            (qf))
+                                    (-> (.getColumnLabel rsmeta i)
+                                        (lf))))
+          (range 1 (inc (.getColumnCount rsmeta))))))
 
 (defn get-unqualified-modified-column-names
   "Given `ResultSetMetaData`, return a vector of unqualified modified column
@@ -60,9 +62,10 @@
 
   Requires the `:label-fn` option."
   [^ResultSetMetaData rsmeta opts]
-  (assert (:label-fn opts) ":label-fn is required")
-  (mapv (fn [^Integer i] (keyword ((:label-fn opts) (.getColumnLabel rsmeta i))))
-        (range 1 (inc (.getColumnCount rsmeta)))))
+  (let [lf (:label-fn opts)]
+    (assert lf ":label-fn is required")
+    (mapv (fn [^Integer i] (keyword (lf (.getColumnLabel rsmeta i))))
+          (range 1 (inc (.getColumnCount rsmeta))))))
 
 (defn- lower-case
   "Converts a string to lower case in the US locale to avoid problems in
@@ -173,8 +176,6 @@
 
   Requires both the `:qualifier-fn` and `:label-fn` options."
   [^ResultSet rs opts]
-  (assert (:qualifier-fn opts) ":qualifier-fn is required")
-  (assert (:label-fn opts) ":label-fn is required")
   (let [rsmeta (.getMetaData rs)
         cols   (get-modified-column-names rsmeta opts)]
     (->MapResultSetBuilder rs rsmeta cols)))
@@ -185,7 +186,6 @@
 
   Requires the `:label-fn` option."
   [^ResultSet rs opts]
-  (assert (:label-fn opts) ":label-fn is required")
   (let [rsmeta (.getMetaData rs)
         cols   (get-unqualified-modified-column-names rsmeta opts)]
     (->MapResultSetBuilder rs rsmeta cols)))
@@ -290,8 +290,6 @@
 
   Requires both the `:qualifier-fn` and `:label-fn` options."
   [^ResultSet rs opts]
-  (assert (:qualifier-fn opts) ":qualifier-fn is required")
-  (assert (:label-fn opts) ":label-fn is required")
   (let [rsmeta (.getMetaData rs)
         cols   (get-modified-column-names rsmeta opts)]
     (->ArrayResultSetBuilder rs rsmeta cols)))
@@ -303,7 +301,6 @@
 
   Requires the `:label-fn` option."
   [^ResultSet rs opts]
-  (assert (:label-fn opts) ":label-fn is required")
   (let [rsmeta (.getMetaData rs)
         cols   (get-unqualified-modified-column-names rsmeta opts)]
     (->ArrayResultSetBuilder rs rsmeta cols)))