heartbeat

技术分享 | Percona Toolkit 使用场景分享

由 十年热恋 提交于 2020-01-10 13:34:40
【推荐】2019 Java 开发者跳槽指南.pdf(吐血整理) >>> 作者：杜金洋 更方便的数据归档 pt-archiver 某些存在时效性的数据，在达到一定条件后，需要进行归档和回收处理。 pt-archiver 工具可以帮助我们快速的进行数据行的归档和回收 # 归档到其他数据库,并删除原表中对应的行 pt-archiver --source h=172.20.134.1,P=5722,u=repl,p=repl,D=sbtest,t=sbtest1,A=utf8 --where "id<=1000" --dest h=172.20.134.3,P=5722,u=dba,p=dba,D=sbtest,t=sbtest1,A=utf8 # 归档到其他数据库, 不删除原表中对应的行 pt-archiver --source h=172.20.134.1,P=5722,u=repl,p=repl,D=sbtest,t=sbtest1,A=utf8 --no-delete --where "id<=1000" --dest h=172.20.134.3,P=5722,u=dba,p=dba,D=sbtest,t=sbtest1,A=utf8 # 归档到文件,并删除原表中对应的行 pt-archiver --source h=172.20.134.1,P=5722,u=repl,p

How to get Heartrate data from Apple's Healthkit?

由 Deadly 提交于 2020-01-03 04:40:09
问题 I am trying to read Heartrate data from Healthkit. I am not able to read that data. I have gone throught this link. Please help me guys..Thank you. 回答1: I managed to read the heart rates from HelathKit using HKSampleQuery. I start reading it from the beginning of the day till 'now'. I also used this link Here is my function and I call it by pressing a button: - (void)readHeartRateWithCompletion:(void (^)(NSArray *results, NSError *error))completion { //get the heart rates NSDate *now =

Ajax Heartbeat using setInterval, Preventing multiple calls at the same time

由 浪尽此生 提交于 2019-12-30 03:27:08
问题 I wish to make an AJAX call using jQuery as a "heartbeat" in the background so that my web application can check for new data. For example every 10 seconds. I have seen on other posts that it is possible to use setInterval() to call a method which does the call every X number of milliseconds. However, what happens if my AJAX call takes more than 10 seconds? I still want it to complete the last request and I don't want another call to be instigated when there is already one in progress. This

Centos 7 下 Corosync + Pacemaker + DRBD + psc + crmsh 实现 mysql 服务高可用

由 萝らか妹 提交于 2019-12-25 12:07:14
一、介绍 高可用，大家可能会想到比较简单的Keepalived，或者更早一点的 heartbeat，也可能会用到 Corosync+Pacemaker，那么他们之间有什么区别。 Heartbeat到了v3版本后，拆分为多个子项目：Heartbeat、cluster-glue、Resource Agent、Pacemaker。 Heartbeat：只负责维护集群各节点的信息以及它们之前通信。 Cluster-glue：当于一个中间层，可以将heartbeat和crm（pacemaker）联系起来，主要包含2个部分，LRM和STONITH； Resource Agent ：用来控制服务启停，监控服务状态的脚本集合，这些脚本将被LRM调用从而实现各种资源启动、停止、监控等等。 pacemaker：原Heartbeat 拆分出来的资源管理器，用来管理整个HA的控制中心，客户端通过pacemaker来配置管理监控整个集群。 它不能提供底层心跳信息传递的功能，它要想与对方节点通信需要借助底层(新拆分的heartbeat或corosync)的心跳传递服务，将信息通告给对方。 Pacemaker 配置文件比较不太容易修改，可以使用命令行界面的crmsh、pcs和图形化界面pygui、hawk等进行管理，看个人喜好。 Heartbeat 和 Corosync 的区别： 1、经过安装heartbeat

How to force/reproduce FullGC in JVM?

由 限于喜欢 提交于 2019-12-24 15:09:56
问题 Is there a way to force/reproduce FullGC in JVM for x seconds ? Basically I needed this to verify root cause of an issue in certain heart beat based app ( a client of zookeeper) EDIT : Does unix command kill -STOP <pid> and kill -CONT <pid> simulate FullGC ( stop the world behaviour) ? 回答1: You can simulate a very long stop-the-world event on HotSpot JVMs which is similar to FullGC from user's point of view. HotSpot doesn't put safepoints into counted int loops, because it assumes that they

Good timeout for heartbeating proto using TCP - Java Sockets

由 两盒软妹~` 提交于 2019-12-22 01:15:54
问题 Im implementing my own proto in Java, it will use a heartbeat over a TCP connection that I also use to transfer messages and files. For the client I am using blocking socket I/O. So here is how Im planning that will work... I will set the socket timeout for K seconds and make the heartbeat stay sending messages in an interval T, so that T < K. If the timeout expires, looks like the server is offline for the client, or vice-versa. The heartbeat is the server sending a String and the Client

Detect Heart Rate using iPhone Camera [duplicate]

由 你离开我真会死。 提交于 2019-12-21 15:04:03
问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: Detecting heart rate using the camera I am working on detecting pulse rate in iOS. I have done some search and now I am able to read heart beats using external bluetooth device which is capable of reading heart beats. But now I am ver curious about detecting pulse using iPhone camera. I am trying to understand How it can be done? What is actual theory behind that? Can any one have an idea behind this? According

Scalable algorithm to detect stale data

由 左心房为你撑大大i 提交于 2019-12-21 06:29:50
问题 Here is the problem: "Agents" installed on many different servers send "heartbeat" signals up to a central server every 5 seconds. How can I find the ones that have missed their heartbeat for more than 10 seconds actively and raise an alert? The problem is simple if you don't think about scalablity. In the simplest form, you can record the timestamp of the latest heartbeat received from each agent in a database table and run a regular query to find the ones older than the threshold. This

Scalable algorithm to detect stale data

由 北城以北 提交于 2019-12-21 06:29:25
问题 Here is the problem: "Agents" installed on many different servers send "heartbeat" signals up to a central server every 5 seconds. How can I find the ones that have missed their heartbeat for more than 10 seconds actively and raise an alert? The problem is simple if you don't think about scalablity. In the simplest form, you can record the timestamp of the latest heartbeat received from each agent in a database table and run a regular query to find the ones older than the threshold. This

ZooKeeper alternatives? (cluster coordination service) [closed]

由 情到浓时终转凉″ 提交于 2019-12-20 07:58:15
问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 3 years ago . ZooKeeper is a highly available coordination service for data centers. It originated in the Hadoop project. One can implement locking, fail over, leader election, group membership and other coordination issues on top of it. Are there any alternatives to ZooKeeper? (free software of course) 回答1: I've looked
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