[tracker/wip/carlosg/insert-perf: 2/13] libtracker-data: Inverse expectations when inserting a resource

[Carlos Garnacho <carlosg src gnome org>]

commit 9a89c7c6b92bec114a85621dabe86605729f665e
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sat Nov 28 18:44:07 2020 +0100

    libtracker-data: Inverse expectations when inserting a resource
    
    Before this change we would first query the ID, and then insert it if non
    existent. Apply the "better to ask for forgiveness than permission"
    principle here, and try to always insert the resource. Only resort to
    queries if there is a constraint violation (meaning the URI already
    exists).
    
    This optimizes insertions over lookups of existing resource IDs, but we
    have other caching layers for the latter.

 src/libtracker-data/tracker-data-update.c | 61 ++++++++++++++++++++-----------
 1 file changed, 40 insertions(+), 21 deletions(-)
---
diff --git a/src/libtracker-data/tracker-data-update.c b/src/libtracker-data/tracker-data-update.c
index 378f434bc..a18bcff1c 100644
--- a/src/libtracker-data/tracker-data-update.c
+++ b/src/libtracker-data/tracker-data-update.c
@@ -785,38 +785,57 @@ ensure_resource_id (TrackerData *data,
        GError *error = NULL;
        gint id;
 
-       id = query_resource_id (data, uri);
+       id = GPOINTER_TO_INT (g_hash_table_lookup (data->update_buffer.resource_cache, uri));
 
-       if (create) {
-               *create = (id == 0);
+       if (id != 0) {
+               if (create)
+                       *create = FALSE;
+               return id;
        }
 
-       if (id == 0) {
-               iface = tracker_data_manager_get_writable_db_interface (data->manager);
+       iface = tracker_data_manager_get_writable_db_interface (data->manager);
 
-               id = tracker_data_update_get_new_service_id (data, &error);
+       id = tracker_data_update_get_new_service_id (data, &error);
 
-               if (id > 0) {
-                       stmt = tracker_db_interface_create_statement (iface, 
TRACKER_DB_STATEMENT_CACHE_TYPE_UPDATE, &error,
-                                                                     "INSERT INTO Resource (ID, Uri, 
BlankNode) VALUES (?, ?, ?)");
-               }
+       if (id > 0) {
+               stmt = tracker_db_interface_create_statement (iface, TRACKER_DB_STATEMENT_CACHE_TYPE_UPDATE, 
&error,
+                                                             "INSERT INTO Resource (ID, Uri, BlankNode) 
VALUES (?, ?, ?)");
+       }
 
-               if (stmt) {
-                       tracker_db_statement_bind_int (stmt, 0, id);
-                       tracker_db_statement_bind_text (stmt, 1, uri);
-                       tracker_db_statement_bind_int (stmt, 2, g_str_has_prefix (uri, "urn:bnode:"));
-                       tracker_db_statement_execute (stmt, &error);
-                       g_object_unref (stmt);
-               }
+       if (stmt) {
+               tracker_db_statement_bind_int (stmt, 0, id);
+               tracker_db_statement_bind_text (stmt, 1, uri);
+               tracker_db_statement_bind_int (stmt, 2, g_str_has_prefix (uri, "urn:bnode:"));
+               tracker_db_statement_execute (stmt, &error);
+               g_object_unref (stmt);
+       }
 
-               if (error) {
-                       g_error ("Could not ensure resource existence: %s", error->message);
-                       g_error_free (error);
+       if (error) {
+               if (g_error_matches (error,
+                                    TRACKER_DB_INTERFACE_ERROR,
+                                    TRACKER_DB_CONSTRAINT)) {
+                       id = query_resource_id (data, uri);
+
+                       if (id != 0) {
+                               if (create)
+                                       *create = FALSE;
+
+                               g_hash_table_insert (data->update_buffer.resource_cache, g_strdup (uri), 
GINT_TO_POINTER (id));
+                               g_error_free (error);
+                               return id;
+                       }
                }
 
-               g_hash_table_insert (data->update_buffer.resource_cache, g_strdup (uri), GINT_TO_POINTER 
(id));
+               g_error ("Could not ensure resource existence: %s", error->message);
+               g_error_free (error);
        }
 
+       if (create)
+               *create = TRUE;
+
+       id = tracker_db_interface_sqlite_get_last_insert_id (iface);
+       g_hash_table_insert (data->update_buffer.resource_cache, g_strdup (uri), GINT_TO_POINTER (id));
+
        return id;
 }