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mongodb 3.2配置内存缓存大小为MB/MongoDB 3.x内存限制配置

由 ⅰ亾dé卋堺 提交于 2020-02-29 13:49:53
原创文章，转载请注明： 转载自 勤奋的小青蛙 本文链接地址: mongodb 3.2配置内存缓存大小为MB/MongoDB 3.x内存限制配置 mongodb占用内存非常高，这是因为官方为了提升存储的效率，设计就这么设计的。 但是大部分的个人开发者所购买的服务器内存并没有那么大，所以，我们需要配置下MongoDB的内存缓存大小，不然mongodb会占用非常多。 官方的配置缓存项处文档 是这么解释的： WiredTiger Options --wiredTigerCacheSizeGB number New in version 3.0. Defines the maximum size of the internal cache that WiredTiger will use for all data. With WiredTiger, MongoDB utilizes both the WiredTiger internal cache and the filesystem cache. Changed in version 3.2: Starting in MongoDB 3.2, the WiredTiger internal cache, by default, will use the larger of either: 60% of RAM minus 1 GB,

Is db.stats() a blocking call for MongoDB?

由 二次信任 提交于 2019-12-23 18:05:36
问题 While researching how to check the size of a MongoDB, I found this comment: Be warned that dbstats blocks your database while it runs, so it's not suitable in production. https://jira.mongodb.org/browse/SERVER-5714 Looking at the linked bug report (which is still open), it quotes the Mongo docs as saying: Command takes some time to run, typically a few seconds unless the .ns file is very large (via use of --nssize). While running other operations may be blocked. However, when I check the

Does performing a partial update on a MongoDb document in WiredTiger provide any advantage over a full document update?

由 若如初见. 提交于 2019-12-22 05:19:18
问题 I'm using a Java driver, although this question is not language specific, to write partial updates to mongodb documents because using the MMAPv1 storage engine the documents are edited in place (in memory) so this provides better performance. This does add considerable development complexity as I could alternatively save the entire document at once and not worry about the details of what exactly got updated. After updating to WiredTiger I learned that this newer storage engine does not edit

WiredTiger and in-place updates

由 生来就可爱ヽ(ⅴ＜●) 提交于 2019-12-18 13:49:27
问题 I have a collection of users. Each user has a field "geoposition" that is updated quite often (every time the user moves significantly). As I want concurrency on the document level instead of the collection level when updating, I am using the WiredTiger storage engine. I learned that with WiredTiger every update in the document results in the creation of a new document: http://learnmongodbthehardway.com/schema/wiredtiger/ WiredTiger does not support in place updates However, this article also

百万级高并发mongodb集群性能数十倍提升优化实践(上篇)

由 人盡茶涼 提交于 2019-12-11 22:40:59
【推荐】2019 Java 开发者跳槽指南.pdf(吐血整理) >>> 背景 线上某集群峰值TPS超过100万/秒左右(主要为写流量，读流量很低)，峰值tps几乎已经到达集群上限，同时平均时延也超过100ms，随着读写流量的进一步增加，时延抖动严重影响业务可用性。该集群采用mongodb天然的分片模式架构，数据均衡的分布于各个分片中，添加片键启用分片功能后实现完美的负载均衡。集群每个节点流量监控如下图所示: 从上图可以看出集群流量比较大，峰值已经突破120万/秒，其中delete过期删除的流量不算在总流量里面(delete由主触发删除，但是主上面不会显示，只会在从节点拉取oplog的时候显示)。如果算上主节点的delete流量，总tps超过150万/秒。 软件优化 在不增加服务器资源的情况下，首先做了如下软件层面的优化，并取得了理想的数倍性能提升： 业务层面优化 Mongodb配置优化 存储引擎优化 2.1 业务层面优化 该集群总文档近百亿条，每条文档记录默认保存三天，业务随机散列数据到三天后任意时间点随机过期淘汰。由于文档数目很多，白天平峰监控可以发现从节点经常有大量delete操作，甚至部分时间点delete删除操作数已经超过了业务方读写流量，因此考虑把delete过期操作放入夜间进行，过期索引添加方法如下: Db.collection.createIndex( {

Does WiredTiger of MongoDb has the performance issue of reallocation as MMAPv1

由 隐身守侯 提交于 2019-12-11 06:23:26
问题 As the MMAPv1 Document said All records are contiguously located on disk, and when a document becomes larger than the allocated record, MongoDB must allocate a new record. New allocations require MongoDB to move a document and update all indexes that refer to the document, which takes more time than in-place updates and leads to storage fragmentation. Changed in version 3.0.0. By default, MongoDB uses Power of 2 Sized Allocations so that every document in MongoDB is stored in a record which

MongoDB - WiredTiger Snapshots vs. Locking

由 耗尽温柔 提交于 2019-12-11 02:04:31
问题 I am not completely understanding how these two features relate to one another in a (WiredTiger) MongoDB program: 1) WiredTiger Snapshots 2) Data Locking If each read operation using the WiredTiger engine is, at read-time, provided with a database level 'snapshot' (so as to create consistency (the C in ACID), why then, do we also need locking? Let's use an example. I perform a query at the Document level (a read operation). Okay, so I know I get the database level snapshot, so that my data is

How to migrate from MMAPv1 to WiredTiger with minimal downtime without mongodump/mongorestore

由 雨燕双飞 提交于 2019-12-08 12:15:57
问题 Most guidelines recommend to use mongodump/mongorestore, but for large product databases downtime can be very long 回答1: You can use replication and an additional server for this or the same server if the load allows. You need 3 running MongoDB instance: Your server you want to update (remind that WiredTiger support since 3.0). Second instance of MongoDB which can be run on an additional server. Database will be temporarily copied to it by the replication. And the third instance of MongoDB is

Does performing a partial update on a MongoDb document in WiredTiger provide any advantage over a full document update?

由 梦想与她 提交于 2019-12-05 07:46:35
I'm using a Java driver, although this question is not language specific, to write partial updates to mongodb documents because using the MMAPv1 storage engine the documents are edited in place (in memory) so this provides better performance. This does add considerable development complexity as I could alternatively save the entire document at once and not worry about the details of what exactly got updated. After updating to WiredTiger I learned that this newer storage engine does not edit documents in place (in memory) but instead allocates new memory for each write (unclear if this means

CentOS7.2中安装MongoDB

由 安稳与你 提交于 2019-12-02 15:11:19
CentOS7.2中安装MongoDB 2018年02月25日 21:28:24 junshangshui 阅读数：9738 标签： mongodb mongodb安装 更多 个人分类： mongodb MongoDB是由C++编写的NoSQL的分布式文件数据库，用的json格式的k-value存储方式。 MongoDB官网 https://www.mongodb.com 一、下载和安装 下载完后文件为mongodb-linux-x86_64-3.6.3.tgz，个人喜欢将它复制到centos中的usr目录下。 在此目录打个一个终端，输入解压命令 tar -xvzf mongodb-linux-x86_64-3.6.3.tgz 再输入命令将这个解压后的文件夹改名 (为将来方便使用，也可不用命令手动去改名) mv mongodb-linux-x86_64-3.6.3 /usr/mongodb 接着可以删除掉压缩包了。 二、配置MongoDB 在/usr/mongodb/bin目录下可看到有可执行程序。 接着配置环境变量到操作系统全局配置文件profile中，先点击计算机，再打开etc目录，搜索proflie文件，在最后一行加入export PATH=$PATH:/usr/mongodb/bin 保存并重启CentOS7就生效了。 重启后直接在桌面打开一个终端，输入命令如下，先在
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