Improve single schema cache (#7214)

* Initial Commit

* fix flaky test

* temporary set ci timeout

* turn off ci check

* fix postgres tests

* fix tests

* node flaky test

* remove improvements

* Update SchemaPerformance.spec.js

* fix tests

* revert ci

* Create Singleton Object

* properly clear cache testing

* Cleanup

* remove fit

* try PushController.spec

* try push test rewrite

* try push enqueue time

* Increase test timeout

* remove pg server creation test

* xit push tests

* more xit

* remove skipped tests

* Fix conflicts

* reduce ci timeout

* fix push tests

* Revert "fix push tests"

This reverts commit 05aba62f1cbbca7d5d3e80b9444529f59407cb56.

* improve initialization

* fix flaky tests

* xit flaky test

* Update CHANGELOG.md

* enable debug logs

* Update LogsRouter.spec.js

* create initial indexes in series

* lint

* horizontal scaling documentation

* Update Changelog

* change horizontalScaling db option

* Add enableSchemaHooks option

* move enableSchemaHooks to databaseOptions

spec/MongoStorageAdapter.spec.js

@@ -18,6 +18,7 @@ const fakeClient = {
 describe_only_db('mongo')('MongoStorageAdapter', () => {
   beforeEach(done => {
     new MongoStorageAdapter({ uri: databaseURI }).deleteAllClasses().then(done, fail);
+    Config.get(Parse.applicationId).schemaCache.clear();
   });
 
   it('auto-escapes symbols in auth information', () => {
@@ -314,6 +315,8 @@ describe_only_db('mongo')('MongoStorageAdapter', () => {
     await user.signUp();
 
     const database = Config.get(Parse.applicationId).database;
+    await database.adapter.dropAllIndexes('_User');
+
     const preIndexPlan = await database.find(
       '_User',
       { username: 'bugs' },
@@ -546,5 +549,33 @@ describe_only_db('mongo')('MongoStorageAdapter', () => {
         });
       });
     });
+
+    describe('watch _SCHEMA', () => {
+      it('should change', async done => {
+        const adapter = new MongoStorageAdapter({
+          uri: databaseURI,
+          collectionPrefix: '',
+          mongoOptions: { enableSchemaHooks: true },
+        });
+        await reconfigureServer({ databaseAdapter: adapter });
+        expect(adapter.enableSchemaHooks).toBe(true);
+        spyOn(adapter, '_onchange');
+        const schema = {
+          fields: {
+            array: { type: 'Array' },
+            object: { type: 'Object' },
+            date: { type: 'Date' },
+          },
+        };
+
+        await adapter.createClass('Stuff', schema);
+        const myClassSchema = await adapter.getClass('Stuff');
+        expect(myClassSchema).toBeDefined();
+        setTimeout(() => {
+          expect(adapter._onchange).toHaveBeenCalled();
+          done();
+        }, 5000);
+      });
+    });
   }
 });