DB: Improve performance using table indexes

fixes #678

lib/Migration/Version000016005Date20190402094721.php

@@ -0,0 +1,52 @@
+<?php
+namespace OCA\Bookmarks\Migration;
+
+use OCP\DB\ISchemaWrapper;
+use OCP\Migration\SimpleMigrationStep;
+use OCP\Migration\IOutput;
+use OCP\IDBConnection;
+
+/**
+ * Auto-generated migration step: Please modify to your needs!
+ */
+class Version000016005Date20190402094721 extends SimpleMigrationStep {
+	private $db;
+
+	public function __construct(IDBConnection $db) {
+		$this->db = $db;
+	}
+
+	/**
+	 * @param IOutput $output
+	 * @param \Closure $schemaClosure The `\Closure` returns a `ISchemaWrapper`
+	 * @param array $options
+	 */
+	public function preSchemaChange(IOutput $output, \Closure $schemaClosure, array $options) {
+	}
+
+	/**
+	 * @param IOutput $output
+	 * @param \Closure $schemaClosure The `\Closure` returns a `ISchemaWrapper`
+	 * @param array $options
+	 * @return null|ISchemaWrapper
+	 */
+	public function changeSchema(IOutput $output, \Closure $schemaClosure, array $options) {
+		/** @var ISchemaWrapper $schema */
+		$schema = $schemaClosure();
+		$table = $schema->getTable('bookmarks_folders_bookmarks');
+		$table->addIndex(['bookmark_id']);
+		$table = $schema->getTable('bookmarks');
+		$table->addIndex(['user_id']);
+		$table = $schema->getTable('bookmarks_folders');
+		$table->addIndex(['user_id']);
+		return $schema;
+	}
+
+	/**
+	 * @param IOutput $output
+	 * @param \Closure $schemaClosure The `\Closure` returns a `ISchemaWrapper`
+	 * @param array $options
+	 */
+	public function postSchemaChange(IOutput $output, \Closure $schemaClosure, array $options) {
+	}
+}