From dev-return-75338-archive-asf-public=cust-asf.ponee.io@zookeeper.apache.org Thu Nov 1 05:39:03 2018 Return-Path: X-Original-To: archive-asf-public@cust-asf.ponee.io Delivered-To: archive-asf-public@cust-asf.ponee.io Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by mx-eu-01.ponee.io (Postfix) with SMTP id 4F07918077A for ; Thu, 1 Nov 2018 05:39:03 +0100 (CET) Received: (qmail 33239 invoked by uid 500); 1 Nov 2018 04:39:01 -0000 Mailing-List: contact dev-help@zookeeper.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@zookeeper.apache.org Delivered-To: mailing list dev@zookeeper.apache.org Received: (qmail 31412 invoked by uid 99); 1 Nov 2018 04:38:59 -0000 Received: from git1-us-west.apache.org (HELO git1-us-west.apache.org) (140.211.11.23) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 01 Nov 2018 04:38:59 +0000 Received: by git1-us-west.apache.org (ASF Mail Server at git1-us-west.apache.org, from userid 33) id 2253AE05E3; Thu, 1 Nov 2018 04:38:59 +0000 (UTC) From: hanm To: dev@zookeeper.apache.org Reply-To: dev@zookeeper.apache.org References: In-Reply-To: Subject: [GitHub] zookeeper pull request #684: ZOOKEEPER-3180: Add response cache to improve t... Content-Type: text/plain Message-Id: <20181101043859.2253AE05E3@git1-us-west.apache.org> Date: Thu, 1 Nov 2018 04:38:59 +0000 (UTC) Github user hanm commented on a diff in the pull request: https://github.com/apache/zookeeper/pull/684#discussion_r229934517 --- Diff: zookeeper-server/src/main/java/org/apache/zookeeper/server/ResponseCache.java --- @@ -0,0 +1,84 @@ +/** + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.zookeeper.server; + +import java.util.Collections; +import java.util.LinkedHashMap; +import java.util.Map; + +import org.apache.jute.Record; +import org.apache.zookeeper.data.Stat; + +@SuppressWarnings("serial") +public class ResponseCache { + private static final int DEFAULT_RESPONSE_CACHE_SIZE = 400; + + private static class Entry { + public Stat stat; + public byte[] data; + } + + private Map cache = Collections.synchronizedMap( + new LRUCache(getResponseCacheSize())); + + public ResponseCache() { + } + + public void put(String path, byte[] data, Stat stat) { + Entry entry = new Entry(); + entry.data = data; + entry.stat = stat; + cache.put(path, entry); + } + + public byte[] get(String key, Stat stat) { + Entry entry = cache.get(key); + if (entry == null) { + return null; + } + if (!stat.equals(entry.stat)) { + // The node has been modified, invalidate cache. + cache.remove(key); + return null; + } else { + return entry.data; + } + } + + private static int getResponseCacheSize() { + String value = System.getProperty("zookeeper.maxResponseCacheSize"); + return value == null ? DEFAULT_RESPONSE_CACHE_SIZE : Integer.parseInt(value); + } + + public static boolean isEnabled() { + return getResponseCacheSize() != 0; + } + + private static class LRUCache extends LinkedHashMap { --- End diff -- nice. ---