diff --git a/java/com/metabase/macaw/ASTWalker.java b/java/com/metabase/macaw/ASTWalker.java
index 0e7991c..68d3dc8 100644
--- a/java/com/metabase/macaw/ASTWalker.java
+++ b/java/com/metabase/macaw/ASTWalker.java
@@ -173,12 +173,12 @@
 import net.sf.jsqlparser.statement.upsert.Upsert;
 
 /**
- * Walks the AST, using JSqlParser's `visit()` methods. Each `visit()` method additionally calls an applicable callback method provided in the `callbacks` map.
- * Supported callbacks have a corresponding key string (see below).
+ * Walks the AST, using JSqlParser's `visit()` methods. Each `visit()` method additionally calls an applicable callback
+ * method provided in the `callbacks` map. Supported callbacks have a corresponding key string (see below).
  *
  * Why this class? Why the callbacks?
  *
- * Clojure is not good at working with Java Visitors. They require over<em>riding</em> various over<em>loaded</em>
+ * Clojure is not good at working with Java visitors. They require over<em>riding</em> various over<em>loaded</em>
  * methods and, in the case of walking a tree (exactly what we want to do here) we of course need to call `visit()`
  * recursively.
  *
diff --git a/src/macaw/core.clj b/src/macaw/core.clj
index 6479cc3..89037b1 100644
--- a/src/macaw/core.clj
+++ b/src/macaw/core.clj
@@ -15,17 +15,17 @@
 (defn query->components
   "Given a parsed query (i.e., a [subclass of] `Statement`) return a map with the `:tables` and `:columns` found within it.
 
-  (Specifically, it returns their fully-qualified names as strings, where 'fully-qualified' means 'as found in the query'.)"
+  (Specifically, it returns their fully-qualified names as strings, where 'fully-qualified' means 'as referred to in the query'; this function doesn't do additional inference work to find out a table's schema.)"
   [^Statement parsed-query]
-  (let [column-names (transient #{})
-        table-names  (transient #{})
+  (let [column-names (atom #{})
+        table-names  (atom #{})
         ast-walker (ASTWalker. {:column (fn [^Column column]
-                                          (conj! column-names (.getColumnName column)))
+                                          (swap! column-names conj (.getColumnName column)))
                                 :table  (fn [^Table table]
-                                          (conj! table-names (.getFullyQualifiedName table)))})]
+                                          (swap! table-names conj (.getFullyQualifiedName table)))})]
     (.walk ast-walker parsed-query)
-    {:columns (persistent! column-names)
-     :tables  (persistent! table-names)}))
+    {:columns @column-names
+     :tables  @table-names}))
 
 (defn parsed-query
   "Main entry point: takes a string query and returns a `Statement` object that can be handled by the other functions."