diff --git a/lib/database-private.h b/lib/database-private.h
index 1a73dacc..9706c17e 100644
--- a/lib/database-private.h
+++ b/lib/database-private.h
@@ -212,6 +212,11 @@ struct _notmuch_database {
     char thread_id_str[17];
     uint64_t last_thread_id;
 
+    /* How many transactions have successfully completed since we last committed */
+    int transaction_count;
+    /* when to commit and reset the counter */
+    int transaction_threshold;
+
     /* error reporting; this value persists only until the
      * next library call. May be NULL */
     char *status_string;
diff --git a/lib/database.cc b/lib/database.cc
index aed05388..31794900 100644
--- a/lib/database.cc
+++ b/lib/database.cc
@@ -1134,13 +1134,21 @@ notmuch_database_end_atomic (notmuch_database_t *notmuch)
     db = notmuch->writable_xapian_db;
     try {
 	db->commit_transaction ();
+	notmuch->transaction_count++;
 
-	/* This is a hack for testing.  Xapian never flushes on a
-	 * non-flushed commit, even if the flush threshold is 1.
-	 * However, we rely on flushing to test atomicity. */
+	/* Xapian never flushes on a non-flushed commit, even if the
+	 * flush threshold is 1.  However, we rely on flushing to test
+	 * atomicity. On the other hand, we can't straight replace
+	 * XAPIAN_FLUSH_THRESHOLD with our autocommit counter, because
+	 * the former also applies outside notmuch atomic
+	 * commits. Hence the follow complicated  test */
 	const char *thresh = getenv ("XAPIAN_FLUSH_THRESHOLD");
-	if (thresh && atoi (thresh) == 1)
+	if ((notmuch->transaction_threshold > 0 &&
+	     notmuch->transaction_count >= notmuch->transaction_threshold) ||
+	    (thresh && atoi (thresh) == 1)) {
 	    db->commit ();
+	    notmuch->transaction_count = 0;
+	}
     } catch (const Xapian::Error &error) {
 	_notmuch_database_log (notmuch, "A Xapian exception occurred committing transaction: %s.\n",
 			       error.get_msg ().c_str ());
diff --git a/lib/open.cc b/lib/open.cc
index 72f1232c..7b95c5b1 100644
--- a/lib/open.cc
+++ b/lib/open.cc
@@ -256,6 +256,8 @@ _alloc_notmuch ()
     notmuch->writable_xapian_db = NULL;
     notmuch->config_path = NULL;
     notmuch->atomic_nesting = 0;
+    notmuch->transaction_count = 0;
+    notmuch->transaction_threshold = 0;
     notmuch->view = 1;
     return notmuch;
 }
@@ -365,6 +367,8 @@ _finish_open (notmuch_database_t *notmuch,
     notmuch_status_t status = NOTMUCH_STATUS_SUCCESS;
     char *incompat_features;
     char *message = NULL;
+    const char *autocommit_str;
+    char *autocommit_end;
     unsigned int version;
     const char *database_path = notmuch_database_get_path (notmuch);
 
@@ -461,6 +465,14 @@ _finish_open (notmuch_database_t *notmuch,
 	if (status)
 	    goto DONE;
 
+	autocommit_str = notmuch_config_get (notmuch, NOTMUCH_CONFIG_AUTOCOMMIT);
+	if (unlikely (! autocommit_str)) {
+	    INTERNAL_ERROR ("missing configuration for autocommit");
+	}
+	notmuch->transaction_threshold = strtoul (autocommit_str, &autocommit_end, 10);
+	if (*autocommit_end != '\0')
+	    INTERNAL_ERROR ("Malformed database database.autocommit value: %s", autocommit_str);
+
 	status = _notmuch_database_setup_standard_query_fields (notmuch);
 	if (status)
 	    goto DONE;
diff --git a/test/T385-transactions.sh b/test/T385-transactions.sh
index ebfec2ed..d8bb502d 100755
--- a/test/T385-transactions.sh
+++ b/test/T385-transactions.sh
@@ -26,7 +26,6 @@ EOF
 test_expect_equal_file EXPECTED OUTPUT
 
 test_begin_subtest "Some changes saved with open transaction"
-test_subtest_known_broken
 notmuch config set database.autocommit 1000
 rm -r ${MAIL_DIR}/.notmuch
 notmuch_with_shim no-close new