[tracker/wip/carlosg/graphs-through-with: 12/15] libtracker-data: Make inline union of all Refcount tables

[Carlos Garnacho <carlosg src gnome org>]

commit d760669a6dbdca243a719eddb77bf3538e706911
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sat Nov 23 20:14:29 2019 +0100

    libtracker-data: Make inline union of all Refcount tables
    
    We don't need a temporary view just for this.

 src/libtracker-data/tracker-data-manager.c | 98 ++++++++++++++----------------
 1 file changed, 45 insertions(+), 53 deletions(-)
---
diff --git a/src/libtracker-data/tracker-data-manager.c b/src/libtracker-data/tracker-data-manager.c
index 699fda2aa..b6632b0a1 100644
--- a/src/libtracker-data/tracker-data-manager.c
+++ b/src/libtracker-data/tracker-data-manager.c
@@ -4905,61 +4905,65 @@ skip_ontology_check:
 }
 
 static gboolean
-data_manager_check_perform_cleanup (TrackerDataManager *manager)
+data_manager_perform_cleanup (TrackerDataManager  *manager,
+                              TrackerDBInterface  *iface,
+                              GError             **error)
 {
        TrackerDBStatement *stmt;
-       TrackerDBInterface *iface;
-       TrackerDBCursor *cursor = NULL;
-       guint count = 0;
-
-       iface = tracker_db_manager_get_writable_db_interface (manager->db_manager);
-       stmt = tracker_db_interface_create_statement (iface, TRACKER_DB_STATEMENT_CACHE_TYPE_NONE,
-                                                     NULL, "SELECT COUNT(*) FROM Graph");
-       if (stmt) {
-               cursor = tracker_db_statement_start_cursor (stmt, NULL);
-               g_object_unref (stmt);
-       }
+       GError *internal_error = NULL;
+       GHashTable *graphs;
+       GHashTableIter iter;
+       const gchar *graph;
+       GString *str;
 
-       if (cursor && tracker_db_cursor_iter_next (cursor, NULL, NULL))
-               count = tracker_db_cursor_get_int (cursor, 0);
+       str = g_string_new ("WITH referencedElements(ID) AS ("
+                           "SELECT ID FROM \"main\".Refcount ");
 
-       g_clear_object (&cursor);
+       graphs = tracker_data_manager_ensure_graphs (manager, iface, &internal_error);
+       if (!graphs)
+               goto fail;
 
-       /* We need to be sure the data is coherent, so we'll refrain from
-        * doing any clean ups till there are elements in the Graph table.
-        *
-        * A database that's been freshly updated to the refcounted
-        * resources will have an empty Graph table, so we might
-        * unintentionally delete graph URNs if we clean up in this state.
-        */
-       if (count == 0)
-               return FALSE;
+       g_hash_table_iter_init (&iter, graphs);
 
-       count = 0;
-       stmt = tracker_db_interface_create_statement (iface, TRACKER_DB_STATEMENT_CACHE_TYPE_NONE, NULL,
-                                                     "SELECT COUNT(*) FROM Resource "
-                                                     "WHERE Resource.ID > %d "
-                                                     "AND Resource.ID NOT IN (SELECT ROWID FROM 
unionGraph_Refcount) "
-                                                     "AND Resource.ID NOT IN (SELECT ID FROM Graph)",
-                                                     TRACKER_ONTOLOGIES_MAX_ID);
-       if (stmt) {
-               cursor = tracker_db_statement_start_cursor (stmt, NULL);
-               g_object_unref (stmt);
+       while (g_hash_table_iter_next (&iter, (gpointer*) &graph, NULL)) {
+               g_string_append_printf (str,
+                                       "UNION ALL SELECT ID FROM \"%s\".Refcount ",
+                                       graph);
        }
 
-       if (cursor && tracker_db_cursor_iter_next (cursor, NULL, NULL))
-               count = tracker_db_cursor_get_int (cursor, 0);
+       g_string_append (str, ") ");
+       g_string_append_printf (str,
+                               "DELETE FROM Resource "
+                               "WHERE Resource.ID > %d "
+                               "AND Resource.ID NOT IN (SELECT ID FROM referencedElements) "
+                               "AND Resource.ID NOT IN (SELECT ID FROM Graph)",
+                               TRACKER_ONTOLOGIES_MAX_ID);
+
+       stmt = tracker_db_interface_create_statement (iface,
+                                                     TRACKER_DB_STATEMENT_CACHE_TYPE_UPDATE,
+                                                     &internal_error,
+                                                     "%s", str->str);
+       g_string_free (str, TRUE);
+
+       if (!stmt)
+               goto fail;
+
+       tracker_db_statement_execute (stmt, &internal_error);
+       g_object_unref (stmt);
 
-       g_clear_object (&cursor);
+fail:
+       if (internal_error) {
+               g_propagate_error (error, internal_error);
+               return FALSE;
+       }
 
-       return count > 0;
+       return TRUE;
 }
 
 void
 tracker_data_manager_dispose (GObject *object)
 {
        TrackerDataManager *manager = TRACKER_DATA_MANAGER (object);
-       TrackerDBStatement *stmt;
        TrackerDBInterface *iface;
        GError *error = NULL;
        gboolean readonly = TRUE;
@@ -4967,25 +4971,13 @@ tracker_data_manager_dispose (GObject *object)
        if (manager->db_manager) {
                readonly = (tracker_db_manager_get_flags (manager->db_manager, NULL, NULL) & 
TRACKER_DB_MANAGER_READONLY) != 0;
 
-               if (!readonly && data_manager_check_perform_cleanup (manager)) {
+               if (!readonly) {
                        /* Delete stale URIs in the Resource table */
                        g_debug ("Cleaning up stale resource URIs");
 
                        iface = tracker_db_manager_get_writable_db_interface (manager->db_manager);
-                       stmt = tracker_db_interface_create_statement (iface, 
TRACKER_DB_STATEMENT_CACHE_TYPE_UPDATE,
-                                                                     &error,
-                                                                     "DELETE FROM Resource "
-                                                                     "WHERE Resource.ID > %d "
-                                                                     "AND Resource.ID NOT IN (SELECT ROWID 
FROM unionGraph_Refcount) "
-                                                                     "AND Resource.ID NOT IN (SELECT ID FROM 
Graph)",
-                                                                     TRACKER_ONTOLOGIES_MAX_ID);
-
-                       if (stmt) {
-                               tracker_db_statement_execute (stmt, &error);
-                               g_object_unref (stmt);
-                       }
 
-                       if (error) {
+                       if (!data_manager_perform_cleanup (manager, iface, &error)) {
                                g_warning ("Could not clean up stale resource URIs: %s\n",
                                           error->message);
                                g_clear_error (&error);