diff --git a/lib/config.cc b/lib/config.cc
index 0b760dbc..c079d752 100644
--- a/lib/config.cc
+++ b/lib/config.cc
@@ -50,6 +50,11 @@ notmuch_database_set_config (notmuch_database_t *notmuch,
     if (status)
 	return status;
 
+    if (! notmuch->config) {
+	if ((status = _notmuch_config_load_from_database (notmuch)))
+	    return status;
+    }
+
     try {
 	notmuch->writable_xapian_db->set_metadata (CONFIG_PREFIX + key, value);
     } catch (const Xapian::Error &error) {
@@ -58,7 +63,13 @@ notmuch_database_set_config (notmuch_database_t *notmuch,
 	_notmuch_database_log (notmuch, "Error: A Xapian exception occurred setting metadata: %s\n",
 			       error.get_msg ().c_str ());
     }
-    return status;
+
+    if (status)
+	return status;
+
+    _notmuch_string_map_set (notmuch->config, key, value);
+
+    return NOTMUCH_STATUS_SUCCESS;
 }
 
 static notmuch_status_t
@@ -84,17 +95,25 @@ notmuch_database_get_config (notmuch_database_t *notmuch,
 			     const char *key,
 			     char **value)
 {
-    std::string strval;
+    const char* stored_val;
     notmuch_status_t status;
 
+    if (! notmuch->config) {
+	if ((status = _notmuch_config_load_from_database (notmuch)))
+	    return status;
+    }
+
     if (! value)
 	return NOTMUCH_STATUS_NULL_POINTER;
 
-    status = _metadata_value (notmuch, key, strval);
-    if (status)
-	return status;
-
-    *value = strdup (strval.c_str ());
+    stored_val = _notmuch_string_map_get (notmuch->config, key);
+    if (! stored_val) {
+	/* XXX in principle this API should be fixed so empty string
+	 * is distinguished from not found */
+	*value = strdup("");
+    } else {
+	*value = strdup (stored_val);
+    }
 
     return NOTMUCH_STATUS_SUCCESS;
 }
@@ -201,3 +220,28 @@ notmuch_config_list_destroy (notmuch_config_list_t *list)
 {
     talloc_free (list);
 }
+
+notmuch_status_t
+_notmuch_config_load_from_database (notmuch_database_t *notmuch)
+{
+    notmuch_status_t status = NOTMUCH_STATUS_SUCCESS;
+    notmuch_config_list_t *list;
+
+    if (notmuch->config == NULL)
+	notmuch->config = _notmuch_string_map_create (notmuch);
+
+    if (unlikely(notmuch->config == NULL))
+	return NOTMUCH_STATUS_OUT_OF_MEMORY;
+
+    status = notmuch_database_get_config_list (notmuch, "", &list);
+    if (status)
+	return status;
+
+    for (; notmuch_config_list_valid (list); notmuch_config_list_move_to_next (list)) {
+	_notmuch_string_map_append (notmuch->config,
+				    notmuch_config_list_key (list),
+				    notmuch_config_list_value (list));
+    }
+
+    return status;
+}
diff --git a/lib/database-private.h b/lib/database-private.h
index c9bc712b..d83cf0d0 100644
--- a/lib/database-private.h
+++ b/lib/database-private.h
@@ -228,6 +228,9 @@ struct _notmuch_database {
      * here, but at least they are small */
     notmuch_string_map_t *user_prefix;
     notmuch_string_map_t *user_header;
+
+    /* Cached and possibly overridden configuration */
+    notmuch_string_map_t *config;
 };
 
 /* Prior to database version 3, features were implied by the database
diff --git a/lib/notmuch-private.h b/lib/notmuch-private.h
index 51016b0b..969caac0 100644
--- a/lib/notmuch-private.h
+++ b/lib/notmuch-private.h
@@ -704,6 +704,9 @@ struct _notmuch_indexopts {
 
 #define EMPTY_STRING(s) ((s)[0] == '\0')
 
+/* config.cc */
+notmuch_status_t
+_notmuch_config_load_from_database (notmuch_database_t * db);
 NOTMUCH_END_DECLS
 
 #ifdef __cplusplus
diff --git a/lib/open.cc b/lib/open.cc
index 1b17e63a..0001794a 100644
--- a/lib/open.cc
+++ b/lib/open.cc
@@ -90,7 +90,7 @@ notmuch_database_open_verbose (const char *path,
     notmuch->exception_reported = false;
     notmuch->status_string = NULL;
     notmuch->path = talloc_strdup (notmuch, path);
-
+    notmuch->config = NULL;
     strip_trailing (notmuch->path, '/');
 
     notmuch->writable_xapian_db = NULL;
@@ -180,6 +180,11 @@ notmuch_database_open_verbose (const char *path,
 	notmuch->query_parser->add_rangeprocessor (notmuch->date_range_processor);
 	notmuch->query_parser->add_rangeprocessor (notmuch->last_mod_range_processor);
 
+	/* Configuration information is needed to set up query parser */
+	status = _notmuch_config_load_from_database (notmuch);
+	if (status)
+	    goto DONE;
+
 	status = _notmuch_database_setup_standard_query_fields (notmuch);
 	if (status)
 	    goto DONE;
diff --git a/lib/prefix.cc b/lib/prefix.cc
index dd7b193d..71a76991 100644
--- a/lib/prefix.cc
+++ b/lib/prefix.cc
@@ -166,8 +166,7 @@ _notmuch_database_setup_standard_query_fields (notmuch_database_t *notmuch)
 notmuch_status_t
 _notmuch_database_setup_user_query_fields (notmuch_database_t *notmuch)
 {
-    notmuch_config_list_t *list;
-    notmuch_status_t status;
+    notmuch_string_map_iterator_t *list;
 
     notmuch->user_prefix = _notmuch_string_map_create (notmuch);
     if (notmuch->user_prefix == NULL)
@@ -177,15 +176,16 @@ _notmuch_database_setup_user_query_fields (notmuch_database_t *notmuch)
     if (notmuch->user_header == NULL)
 	return NOTMUCH_STATUS_OUT_OF_MEMORY;
 
-    status = notmuch_database_get_config_list (notmuch, CONFIG_HEADER_PREFIX, &list);
-    if (status)
-	return status;
+    list = _notmuch_string_map_iterator_create (notmuch->config, CONFIG_HEADER_PREFIX, FALSE);
+    if (! list)
+	INTERNAL_ERROR ("unable to read headers from configuration");
 
-    for (; notmuch_config_list_valid (list); notmuch_config_list_move_to_next (list)) {
+    for (; _notmuch_string_map_iterator_valid (list);
+	 _notmuch_string_map_iterator_move_to_next (list)) {
 
 	prefix_t query_field;
 
-	const char *key = notmuch_config_list_key (list)
+	const char *key = _notmuch_string_map_iterator_key (list)
 			  + sizeof (CONFIG_HEADER_PREFIX) - 1;
 
 	_notmuch_string_map_append (notmuch->user_prefix,
@@ -194,7 +194,7 @@ _notmuch_database_setup_user_query_fields (notmuch_database_t *notmuch)
 
 	_notmuch_string_map_append (notmuch->user_header,
 				    key,
-				    notmuch_config_list_value (list));
+				    _notmuch_string_map_iterator_value (list));
 
 	query_field.name = talloc_strdup (notmuch, key);
 	query_field.prefix = _user_prefix (notmuch, key);
@@ -204,7 +204,7 @@ _notmuch_database_setup_user_query_fields (notmuch_database_t *notmuch)
 	_setup_query_field_default (&query_field, notmuch);
     }
 
-    notmuch_config_list_destroy (list);
+    _notmuch_string_map_iterator_destroy (list);
 
     return NOTMUCH_STATUS_SUCCESS;
 }
diff --git a/test/T562-lib-database.sh b/test/T562-lib-database.sh
index dd4f2566..887851dd 100755
--- a/test/T562-lib-database.sh
+++ b/test/T562-lib-database.sh
@@ -340,7 +340,7 @@ test_expect_equal_file EXPECTED OUTPUT
 test_begin_subtest "get config from closed database"
 cat c_head - c_tail <<'EOF' | test_C ${MAIL_DIR}
     {
-        const char *result;
+        char *result;
         EXPECT0(notmuch_database_close (db));
         stat = notmuch_database_get_config (db, "foo", &result);
         printf("%d\n",  stat == NOTMUCH_STATUS_XAPIAN_EXCEPTION);
@@ -348,9 +348,8 @@ cat c_head - c_tail <<'EOF' | test_C ${MAIL_DIR}
 EOF
 cat <<EOF > EXPECTED
 == stdout ==
-1
+0
 == stderr ==
-Error: A Xapian exception occurred getting metadata: Database has been closed
 EOF
 test_expect_equal_file EXPECTED OUTPUT
 
@@ -376,7 +375,7 @@ cat c_head - c_tail <<'EOF' | test_C ${MAIL_DIR}
         notmuch_indexopts_t *result;
         EXPECT0(notmuch_database_close (db));
         result = notmuch_database_get_default_indexopts (db);
-        printf("%d\n",  result == NULL);
+        printf("%d\n", result != NULL);
     }
 EOF
 cat <<EOF > EXPECTED