Add option to re-use schema cache between requests (#2979)

* Add option to reuse database controller between requests. Clear schema cache when deleting everything

* Add test

* Rename setting to persistSchemaCache to more accurately reflect effect

* Repurpose option to determine whether to randomize cache prefix. Restore Config.js controller creation. Add tests

* Fix bug with missing parameter passed to to SchemaCache

* Renaming and formatting

* Fix property name typo

* Rename option to avoid double negative and still be falsey by default. Style fix

spec/EnableSingleSchemaCache.spec.js

@@ -0,0 +1,49 @@
+const auth = require('../src/Auth');
+const Config = require('../src/Config');
+const rest = require('../src/rest');
+
+describe('Enable single schema cache', () => {
+  beforeEach((done) => {
+    reconfigureServer({
+      enableSingleSchemaCache: true,
+      schemaCacheTTL: 30000
+    }).then(() => {
+      done();
+    });
+  });
+
+  it('can perform multiple create and query operations', (done) => {
+    let config = fakeRequestForConfig();
+    let nobody = auth.nobody(config);
+    rest.create(config, nobody, 'Foo', {type: 1}).then(() => {
+      config = fakeRequestForConfig();
+      nobody = auth.nobody(config);
+      return rest.create(config, nobody, 'Foo', {type: 2});
+    }).then(() => {
+      config = fakeRequestForConfig();
+      nobody = auth.nobody(config);
+      return rest.create(config, nobody, 'Bar');
+    }).then(() => {
+      config = fakeRequestForConfig();
+      nobody = auth.nobody(config);
+      return rest.find(config, nobody, 'Bar', {type: 1});
+    }).then((response) => {
+      fail('Should throw error');
+      done();
+    }, (error) => {
+      config = fakeRequestForConfig();
+      nobody = auth.nobody(config);
+      expect(error).toBeDefined();
+      return rest.find(config, nobody, 'Foo', {type: 1});
+    }).then((response) => {
+      config = fakeRequestForConfig();
+      nobody = auth.nobody(config);
+      expect(response.results.length).toEqual(1);
+      done();
+    });
+  });
+});
+
+const fakeRequestForConfig = function() {
+  return new Config('test');
+};

spec/SchemaCache.spec.js

@@ -3,35 +3,66 @@ var InMemoryCacheAdapter = require('../src/Adapters/Cache/InMemoryCacheAdapter')
 var SchemaCache = require('../src/Controllers/SchemaCache').default;
 
 describe('SchemaCache', () => {
-	var schemaCache;
+  let cacheController;
 
   beforeEach(() => {
-		var cacheAdapter = new InMemoryCacheAdapter({});
-		var cacheController = new CacheController(cacheAdapter, 'appId');
-		schemaCache = new SchemaCache(cacheController);
+    const cacheAdapter = new InMemoryCacheAdapter({});
+    cacheController = new CacheController(cacheAdapter, 'appId');
   });
 
   it('can retrieve a single schema after all schemas stored', (done) => {
-		var allSchemas = [{
+    const schemaCache = new SchemaCache(cacheController);
+    const allSchemas = [{
       className: 'Class1'
     }, {
       className: 'Class2'
     }];
-		schemaCache.setAllClasses(allSchemas);
-		schemaCache.getOneSchema('Class2').then((schema) => {
+    schemaCache.setAllClasses(allSchemas).then(() => {
+      return schemaCache.getOneSchema('Class2');
+    }).then((schema) => {
       expect(schema).not.toBeNull();
       done();
     });
   });
 
   it('does not return all schemas after a single schema is stored', (done) => {
-		var schema = {
+    const schemaCache = new SchemaCache(cacheController);
+    const schema = {
       className: 'Class1'
     };
-		schemaCache.setOneSchema('Class1', schema);
-		schemaCache.getAllClasses().then((allSchemas) => {
+    schemaCache.setOneSchema(schema.className, schema).then(() => {
+      return schemaCache.getAllClasses();
+    }).then((allSchemas) => {
       expect(allSchemas).toBeNull();
       done();
     });
   });
+
+  it('doesn\'t persist cached data by default', (done) => {
+    const schemaCache = new SchemaCache(cacheController);
+    const schema = {
+      className: 'Class1'
+    };
+    schemaCache.setOneSchema(schema.className, schema).then(() => {
+      const anotherSchemaCache = new SchemaCache(cacheController);
+      return anotherSchemaCache.getOneSchema(schema.className).then((schema) => {
+        expect(schema).toBeNull();
+        done();
+      });
+    });
+  });
+
+  it('can persist cached data', (done) => {
+    const schemaCache = new SchemaCache(cacheController, 5000, true);
+    const schema = {
+      className: 'Class1'
+    };
+    schemaCache.setOneSchema(schema.className, schema).then(() => {
+      const anotherSchemaCache = new SchemaCache(cacheController, 5000, true);
+      return anotherSchemaCache.getOneSchema(schema.className).then((schema) => {
+        expect(schema).not.toBeNull();
+        done();
+      });
+    });
+  });
 });

src/Config.js

@@ -37,11 +37,12 @@ export class Config {
 
     // Create a new DatabaseController per request
     if (cacheInfo.databaseController) {
-      const schemaCache = new SchemaCache(cacheInfo.cacheController, cacheInfo.schemaCacheTTL);
+      const schemaCache = new SchemaCache(cacheInfo.cacheController, cacheInfo.schemaCacheTTL, cacheInfo.enableSingleSchemaCache);
       this.database = new DatabaseController(cacheInfo.databaseController.adapter, schemaCache);
     }
 
     this.schemaCacheTTL = cacheInfo.schemaCacheTTL;
+    this.enableSingleSchemaCache = cacheInfo.enableSingleSchemaCache;
 
     this.serverURL = cacheInfo.serverURL;
     this.publicServerURL = removeTrailingSlash(cacheInfo.publicServerURL);

src/Controllers/DatabaseController.js

@@ -515,7 +515,10 @@ DatabaseController.prototype.canAddField = function(schema, className, object, a
 // Returns a promise.
 DatabaseController.prototype.deleteEverything = function() {
   this.schemaPromise = null;
-  return this.adapter.deleteAllClasses();
+  return Promise.all([
+    this.adapter.deleteAllClasses(),
+    this.schemaCache.clear()
+  ]);
 };
 
 // Finds the keys in a query. Returns a Set. REST format only

src/Controllers/SchemaCache.js

@@ -8,13 +8,16 @@ import defaults from '../defaults';
 export default class SchemaCache {
   cache: Object;
 
-  constructor(cacheController, ttl = defaults.schemaCacheTTL) {
+  constructor(cacheController, ttl = defaults.schemaCacheTTL, randomizePrefix = false) {
     this.ttl = ttl;
     if (typeof ttl == 'string') {
       this.ttl = parseInt(ttl);
     }
     this.cache = cacheController;
-    this.prefix = SCHEMA_CACHE_PREFIX+randomString(20);
+    this.prefix = SCHEMA_CACHE_PREFIX;
+    if (!randomizePrefix) {
+      this.prefix += randomString(20);
+    }
   }
 
   put(key, value) {

src/ParseServer.js

@@ -139,6 +139,7 @@ class ParseServer {
     expireInactiveSessions = defaults.expireInactiveSessions,
     revokeSessionOnPasswordReset = defaults.revokeSessionOnPasswordReset,
     schemaCacheTTL = defaults.schemaCacheTTL, // cache for 5s
+    enableSingleSchemaCache = false,
     __indexBuildCompletionCallbackForTests = () => {},
   }) {
     // Initialize the node client SDK automatically
@@ -181,7 +182,7 @@ class ParseServer {
     const analyticsController = new AnalyticsController(analyticsControllerAdapter);
 
     const liveQueryController = new LiveQueryController(liveQuery);
-    const databaseController = new DatabaseController(databaseAdapter, new SchemaCache(cacheController, schemaCacheTTL));
+    const databaseController = new DatabaseController(databaseAdapter, new SchemaCache(cacheController, schemaCacheTTL, enableSingleSchemaCache));
     const hooksController = new HooksController(appId, databaseController, webhookKey);
 
     const dbInitPromise = databaseController.performInitizalization();
@@ -221,7 +222,8 @@ class ParseServer {
       jsonLogs,
       revokeSessionOnPasswordReset,
       databaseController,
-      schemaCacheTTL
+      schemaCacheTTL,
+      enableSingleSchemaCache
     });
 
     // To maintain compatibility. TODO: Remove in some version that breaks backwards compatability

src/cli/definitions/parse-server.js

@@ -195,6 +195,11 @@ export default {
     help: "The TTL for caching the schema for optimizing read/write operations. You should put a long TTL when your DB is in production. default to 0; disabled.",
     action: numberParser("schemaCacheTTL"),
   },
+  "enableSingleSchemaCache": {
+    env: "PARSE_SERVER_ENABLE_SINGLE_SCHEMA_CACHE",
+    help: "Use a single schema cache shared across requests. Reduces number of queries made to _SCHEMA. Defaults to false, i.e. unique schema cache per request.",
+    action: booleanParser
+  },
   "cluster": {
     help: "Run with cluster, optionally set the number of processes default to os.cpus().length",
     action: numberOrBoolParser("cluster")