libtracker-sparql/direct: Use TrackerBatch beneath update_array_async

When using update_array_async(), we attempt to process the entire set
of updates as a transaction, that involves dealing with it as a single
SPARQL string (i.e. concatenated in a separate copy in memory).

Since this single huge string may be duplicated for other purposes in
libtracker-data internals (e.g. unescaping \u and \U sequences), the
impact of dealing with it as a single string can get worse.

Use TrackerBatch underneath instead, this means queries are treated
individually for parsing purposes, these possible string duplications
happen over these smaller chunks, and memory does not peak as much
with large sets of updates.

Locally, this reduced the peak heap usage from 95MB to 85MB in
tracker-miner-fs-3 when dealing with document metadata coming from
tracker-extract-3.

1 files changed, 27 insertions, 18 deletions

diff --git a/src/libtracker-sparql/direct/tracker-direct.c b/src/libtracker-sparql/direct/tracker-direct.c
index ff4642a9a..7f5131deb 100644
--- a/src/libtracker-sparql/direct/tracker-direct.c
+++ b/src/libtracker-sparql/direct/tracker-direct.c
@@ -848,6 +848,26 @@ tracker_direct_connection_update_finish (TrackerSparqlConnection  *self,
 }
 
 static void
+on_batch_finished (GObject      *source,
+                   GAsyncResult *result,
+                   gpointer      user_data)
+{
+	TrackerBatch *batch = TRACKER_BATCH (source);
+	GTask *task = user_data;
+	GError *error = NULL;
+	gboolean retval;
+
+	retval = tracker_batch_execute_finish (batch, result, &error);
+
+	if (retval)
+		g_task_return_boolean (task, TRUE);
+	else
+		g_task_return_error (task, error);
+
+	g_object_unref (task);
+}
+
+static void
 tracker_direct_connection_update_array_async (TrackerSparqlConnection  *self,
                                               gchar                   **updates,
                                               gint                      n_updates,
@@ -855,29 +875,18 @@ tracker_direct_connection_update_array_async (TrackerSparqlConnection  *self,
                                               GAsyncReadyCallback       callback,
                                               gpointer                  user_data)
 {
-	TrackerDirectConnectionPrivate *priv;
-	TrackerDirectConnection *conn;
-	TaskData *task_data;
+	TrackerBatch *batch;
 	GTask *task;
-	gchar *concatenated;
-	gchar **array_copy;
-
-	conn = TRACKER_DIRECT_CONNECTION (self);
-	priv = tracker_direct_connection_get_instance_private (conn);
+	gint i;
 
-	/* Make a NULL-terminated array and concatenate it */
-	array_copy = g_new0 (gchar *, n_updates + 1);
-	memcpy (array_copy, updates, n_updates * sizeof (gchar *));
-	concatenated = g_strjoinv ("\n", array_copy);
-	g_free (array_copy);
+	batch = tracker_sparql_connection_create_batch (self);
 
-	task_data = task_data_query_new (TASK_TYPE_UPDATE, concatenated, g_free);
+	for (i = 0; i < n_updates; i++)
+		tracker_batch_add_sparql (batch, updates[i]);
 
 	task = g_task_new (self, cancellable, callback, user_data);
-	g_task_set_task_data (task, task_data,
-	                      (GDestroyNotify) task_data_free);
-
-	g_thread_pool_push (priv->update_thread, task, NULL);
+	tracker_batch_execute_async (batch, cancellable, on_batch_finished, task);
+	g_object_unref (batch);
 }
 
 static gboolean