Use schema collection instead of adaptive collection for all schema operations.

src/Adapters/Storage/Mongo/MongoCollection.js

@@ -76,17 +76,6 @@ export default class MongoCollection {
     return this._mongoCollection.updateMany(query, update);
   }
 
-  // Atomically find and delete an object based on query.
-  // The result is the promise with an object that was in the database before deleting.
-  // Postgres Note: Translates directly to `DELETE * FROM ... RETURNING *`, which will return data after delete is done.
-  findOneAndDelete(query) {
-    // arguments: query, sort
-    return this._mongoCollection.findAndRemove(query, []).then(document => {
-      // Value is the object where mongo returns multiple fields.
-      return document.value;
-    });
-  }
-
   deleteOne(query) {
     return this._mongoCollection.deleteOne(query);
   }

src/Controllers/DatabaseController.js

@@ -63,7 +63,7 @@ DatabaseController.prototype.validateClassName = function(className) {
 DatabaseController.prototype.loadSchema = function(acceptor = returnsTrue) {
 
   if (!this.schemaPromise) {
-    this.schemaPromise = this.adaptiveCollection('_SCHEMA').then(collection => {
+    this.schemaPromise = this.schemaCollection().then(collection => {
       delete this.schemaPromise;
       return Schema.load(collection);
     });
@@ -74,7 +74,7 @@ DatabaseController.prototype.loadSchema = function(acceptor = returnsTrue) {
     if (acceptor(schema)) {
       return schema;
     }
-    this.schemaPromise = this.adaptiveCollection('_SCHEMA').then(collection => {
+    this.schemaPromise = this.schemaCollection().then(collection => {
       delete this.schemaPromise;
       return Schema.load(collection);
     });

src/Routers/SchemasRouter.js

@@ -15,23 +15,22 @@ function classNameMismatchResponse(bodyClass, pathClass) {
 }
 
 function getAllSchemas(req) {
-  return req.config.database.adaptiveCollection('_SCHEMA')
-    .then(collection => collection.find({}))
+  return req.config.database.schemaCollection()
+    .then(collection => collection.getAllSchemas())
     .then(schemas => schemas.map(Schema.mongoSchemaToSchemaAPIResponse))
     .then(schemas => ({ response: { results: schemas } }));
 }
 
 function getOneSchema(req) {
   const className = req.params.className;
-  return req.config.database.adaptiveCollection('_SCHEMA')
-    .then(collection => collection.find({ '_id': className }, { limit: 1 }))
-    .then(results => {
-      if (results.length != 1) {
+  return req.config.database.schemaCollection()
+    .then(collection => collection.findSchema(className))
+    .then(mongoSchema => {
+      if (!mongoSchema) {
         throw new Parse.Error(Parse.Error.INVALID_CLASS_NAME, `Class ${className} does not exist.`);
       }
-      return results[0];
-    })
-    .then(schema => ({ response: Schema.mongoSchemaToSchemaAPIResponse(schema) }));
+      return { response: Schema.mongoSchemaToSchemaAPIResponse(mongoSchema) };
+    });
 }
 
 function createSchema(req) {
@@ -142,8 +141,8 @@ function deleteSchema(req) {
     .then(() => {
       // We've dropped the collection now, so delete the item from _SCHEMA
       // and clear the _Join collections
-      return req.config.database.adaptiveCollection('_SCHEMA')
-        .then(coll => coll.findOneAndDelete({ _id: req.params.className }))
+      return req.config.database.schemaCollection()
+        .then(coll => coll.findAndDeleteSchema(req.params.className))
         .then(document => {
           if (document === null) {
             //tried to delete non-existent class

src/Schema.js

@@ -184,7 +184,7 @@ class Schema {
   reloadData() {
     this.data = {};
     this.perms = {};
-    return this._collection.find({}).then(results => {
+    return this._collection.getAllSchemas().then(results => {
       for (let obj of results) {
         let className = null;
         let classData = {};
@@ -231,7 +231,7 @@ class Schema {
       return Promise.reject(mongoObject);
     }
 
-    return this._collection.insertOne(mongoObject.result)
+    return this._collection.addSchema(className, mongoObject.result)
       .then(result => result.ops[0])
       .catch(error => {
         if (error.code === 11000) { //Mongo's duplicate key error
@@ -268,7 +268,7 @@ class Schema {
         'schema is frozen, cannot add: ' + className);
     }
     // We don't have this class. Update the schema
-    return this._collection.insertOne({ _id: className }).then(() => {
+    return this._collection.addSchema(className).then(() => {
       // The schema update succeeded. Reload the schema
       return this.reloadData();
     }, () => {
@@ -288,14 +288,13 @@ class Schema {
 
   // Sets the Class-level permissions for a given className, which must exist.
   setPermissions(className, perms) {
-    var query = {_id: className};
     var update = {
       _metadata: {
         class_permissions: perms
       }
     };
     update = {'$set': update};
-    return this._collection.updateOne(query, update).then(() => {
+    return this._collection.updateSchema(className, update).then(() => {
       // The update succeeded. Reload the schema
       return this.reloadData();
     });
@@ -353,12 +352,12 @@ class Schema {
     // We don't have this field. Update the schema.
     // Note that we use the $exists guard and $set to avoid race
     // conditions in the database. This is important!
-    var query = { _id: className };
+    let query = {};
     query[key] = { '$exists': false };
     var update = {};
     update[key] = type;
     update = {'$set': update};
-    return this._collection.upsertOne(query, update).then(() => {
+    return this._collection.upsertSchema(className, query, update).then(() => {
       // The update succeeded. Reload the schema
       return this.reloadData();
     }, () => {
@@ -428,7 +427,7 @@ class Schema {
               });
           })
           // Save the _SCHEMA object
-          .then(() => this._collection.updateOne({ _id: className }, { $unset: { [fieldName]: null } }));
+          .then(() => this._collection.updateSchema(className, { $unset: { [fieldName]: null } }));
       });
   }