[core] Update SQLite schema with WAL journal mode and normal sync

platform/default/mbgl/storage/offline_database.cpp

@@ -48,7 +48,8 @@ void OfflineDatabase::ensureSchema() {
             case 0: break; // cache-only database; ok to delete
             case 1: break; // cache-only database; ok to delete
             case 2: migrateToVersion3(); // fall through
-            case 3: return;
+            case 3: migrateToVersion4(); // fall through
+            case 4: return;
             default: throw std::runtime_error("unknown schema version");
             }
 
@@ -79,8 +80,10 @@ void OfflineDatabase::ensureSchema() {
 
         // If you change the schema you must write a migration from the previous version.
         db->exec("PRAGMA auto_vacuum = INCREMENTAL");
+        db->exec("PRAGMA synchronous = NORMAL");
+        db->exec("PRAGMA journal_mode = WAL");
         db->exec(schema);
-        db->exec("PRAGMA user_version = 3");
+        db->exec("PRAGMA user_version = 4");
     } catch (...) {
         Log::Error(Event::Database, "Unexpected error creating database schema: %s", util::toString(std::current_exception()).c_str());
         throw;
@@ -111,6 +114,12 @@ void OfflineDatabase::migrateToVersion3() {
     db->exec("PRAGMA user_version = 3");
 }
 
+void OfflineDatabase::migrateToVersion4() {
+    db->exec("PRAGMA synchronous = NORMAL");
+    db->exec("PRAGMA journal_mode = WAL");
+    db->exec("PRAGMA user_version = 4");
+}
+
 OfflineDatabase::Statement OfflineDatabase::getStatement(const char * sql) {
     auto it = statements.find(sql);
 

platform/default/mbgl/storage/offline_database.hpp

@@ -60,6 +60,7 @@ class OfflineDatabase : private util::noncopyable {
     void ensureSchema();
     void removeExisting();
     void migrateToVersion3();
+    void migrateToVersion4();
 
     class Statement {
     public:

platform/ios/CHANGELOG.md

@@ -40,6 +40,7 @@ Mapbox welcomes participation and contributions from everyone. Please read [CONT
 ### Other changes
 
 * Fixed a crash that sometimes occurred when initializing an MGLMapView. ([#5932](https://github.com/mapbox/mapbox-gl-native/pull/5932))
+* Improved offline and ambient cache database performance. ([#5796](https://github.com/mapbox/mapbox-gl-native/pull/5796))
 * As the user zooms in, tiles from lower zoom levels are scaled up until tiles for higher zoom levels are loaded. ([#5143](https://github.com/mapbox/mapbox-gl-native/pull/5143))
 * MGLMapDebugOverdrawVisualizationMask no longer has any effect in Release builds of the SDK. This debug mask has been disabled for performance reasons. ([#5555](https://github.com/mapbox/mapbox-gl-native/pull/5555))
 * Fixed a typo in the documentation for the MGLCompassDirectionFormatter class. ([#5879](https://github.com/mapbox/mapbox-gl-native/pull/5879))

platform/macos/CHANGELOG.md

@@ -5,6 +5,7 @@
 * Fixed an issue causing code signing failures and bloating the framework. ([#5850](https://github.com/mapbox/mapbox-gl-native/pull/5850))
 * Xcode 7.3 or higher is now required for using this SDK. ([#6059](https://github.com/mapbox/mapbox-gl-native/issues/6059))
 * A new runtime styling API allows you to adjust the style and content of the base map dynamically. All the options available in [Mapbox Studio](https://www.mapbox.com/studio/) are now exposed via MGLStyle and subclasses of MGLStyleLayer and MGLSource. ([#5727](https://github.com/mapbox/mapbox-gl-native/pull/5727))
+* Improved offline and ambient cache database performance. ([#5796](https://github.com/mapbox/mapbox-gl-native/pull/5796))
 * Added `showAnnotations:animated:` and `showAnnotations:edgePadding:animated:`, which moves the map viewport to show the specified annotations. ([#5749](https://github.com/mapbox/mapbox-gl-native/pull/5749))
 * To make an MGLPolyline or MGLPolygon span the antimeridian, specify coordinates with longitudes greater than 180° or less than −180°. ([#6088](https://github.com/mapbox/mapbox-gl-native/pull/6088))
 * MGLMapView’s `styleURL` property can now be set to an absolute file URL. ([#6026](https://github.com/mapbox/mapbox-gl-native/pull/6026))

test/storage/offline_database.cpp

@@ -559,18 +559,18 @@ TEST(OfflineDatabase, MigrateFromV2Schema) {
 
     // v2.db is a v2 database containing a single offline region with a small number of resources.
 
-    deleteFile("test/fixtures/offline_database/v3.db");
-    writeFile("test/fixtures/offline_database/v3.db", util::read_file("test/fixtures/offline_database/v2.db"));
+    deleteFile("test/fixtures/offline_database/v4.db");
+    writeFile("test/fixtures/offline_database/v4.db", util::read_file("test/fixtures/offline_database/v2.db"));
 
     {
-        OfflineDatabase db("test/fixtures/offline_database/v3.db", 0);
+        OfflineDatabase db("test/fixtures/offline_database/v4.db", 0);
         auto regions = db.listRegions();
         for (auto& region : regions) {
             db.deleteRegion(std::move(region));
         }
     }
 
-    EXPECT_EQ(3, databaseUserVersion("test/fixtures/offline_database/v3.db"));
-    EXPECT_LT(databasePageCount("test/fixtures/offline_database/v3.db"),
+    EXPECT_EQ(4, databaseUserVersion("test/fixtures/offline_database/v4.db"));
+    EXPECT_LT(databasePageCount("test/fixtures/offline_database/v4.db"),
               databasePageCount("test/fixtures/offline_database/v2.db"));
 }