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[转]再见 NoSQL！

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为解决大规模数据集合多重数据种类带来的挑战，NoSQL 应运而生，但现在却也遇到了诸多问题，本文作者 Rick Negrin，曾在微软工作 12 年，并在 SQL Server 团队度过大部分光阴，他提出，是时候「和 NoSQL 说再见」了！作者 | Rick Negrin 译者 | 明明如月责编 | 唐小引头图 | CSDN 下载自东方 IC 出品 | CSDN（ID：CSDNnews）以下为译文：是时候承认我们早就知道的事实了： NoSQL 并不适合现代应用程序，我们该对它说再见了。由于数据超过了数据库能够处理的规模，NoSQL 技术就应运而生。这种新型的数据服务的兴起解决了十年前它出现时网络和数据快速增长的问题。NoSQL 还提供了冷存储或批量访问 PB 级数据的低成本的新途径。然而，由于急于解决大数据和高并发的挑战，NoSQL 放弃了数据库的一些高性能和简单易用的核心特性。对大数据和高并发与高性能和易用性做出的权衡是 NoSQL 在数据库领域做出的最大贡献。将大数据和成熟的关系型结构和灵活性结合到一起，从而产生了一个可伸缩的关系数据库，造就了一场变革。关系型数据库的发展创造了一个全新的系统，可以处理几乎所有的任务，具有现代应用程序所需的可伸缩性、可靠性和可用性要求。随着从传统的工作任务（例如事务处理应用程序和业务分析）到更新的工作任务

MemSQL takes 15GB memory for 10MB of data

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问题 I have installed memsql 5.1.2 in following manner with following resources. Google cloud server HDD: 100GB Machine type: n1-standard-4 (4 vCPUs, 15 GB memory) Implementation: 2 MEMSQL NODES running on same machine on the following ports 3306 Master Aggregator 3307 Leaf Resource Utilization: Memory 14.16 GB / 14.69 GB Paging 0 B/s Database size - 10MB 1818 memsql 1.1% 77% /var/lib/memsql/leaf-3307/memsqld --defaults-file=/var/lib/memsql/leaf-3307/memsql.cnf --pid-file=/var/lib/memsql/leaf-3307

Bad distributed join plan: result table shard keys do not match

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问题 We are very new to memsql/mysql and we are trying to play around with a memsql installation. It is installed on a CentOS7 virtual machine and we are running version 5.1.0 of MemSQL. We are receiving the error from one of the queries we are attempting: ERROR 1889 (HY000): Bad distributed join plan: result table shard keys do not match. Please contact MemSQL support at support@memsql.com. On one of our queries We have two tables: CREATE TABLE `MyObjects` ( `Id` INT NOT NULL AUTO_INCREMENT,

Bad distributed join plan: result table shard keys do not match

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How to change IP addresses of memsql nodes

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问题 I'm testing out memsql for a project by running it on a laptop in its simplest configuration. It was working fine at home with an IP address of 192.168.0.22. When I take the laptop in to work, it gets a different IP address (10.0.1.35), and when I start up the server, it's unable to bring the nodes online. I get this message in the ops app: 192.168.0.22:3306: This MemSQL node is offline, but MemSQL Ops expects it to be online. 192.168.0.22:3307: This MemSQL node is offline, but MemSQL Ops

MemSQL - Surrogate key as Primary and different unique keys at the same time in table creation

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问题 I have a situation that I need to have a surrogate key ( id ) in place of a composite key (4 field combined to be unique: project_id, dataset_id, table_id, view_name ) to easily refer that in other tables. So to do this I used id field as Primary key and other 4 fields mentioned above as unique keys. This is allowed in MySQL but not in MemSQL. Error Code: 1895. The unique key named: 'project_id' must contain all columns specified in the primary key when no shard key is declared So I added the

Memsql: why memory usage is so high?

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问题 Firstly, forgive my poor English. My test environment : [centos 6.5 16G RAM] * 2 MemSQL Community:MemSQL Ops Server Version:4.1.10 and MemSQL Version:4.1.2 my cluster picgure leaf node,top picgure Yeah, just one master and one leaf. I set maximum_memory = 10G on the leaf node. Here is the question: Only 334M memory is used for table data, but the leaf node used 13.34G memory. Why is that? By the way, my use scenario is just like "Speed Test", batch insert and batch delete. Thank you very much

What is the correct way of using memSQL Connection object inside call method of Apache Spark code

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问题 I have a spark code where the code inside Call method makes call to the memSQL database for reading from a table. My code opens a new connection object each time and closes it after the task is done. This call is made from inside the Call method. This works fine but the execution time for Spark job becomes high. What would be a better way to do this so that the spark code execution time is reduced. Thank You. 回答1: You can use one connection per partition, like this: rdd.foreachPartition

Reading JSON from MEMSQL

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问题 Having a problem with JSON / MEMSQL. Here's my table: CREATE TABLE `MEMSQLPOLYGLOT` ( ID BIGINT AUTO_INCREMENT, `DATA` JSON NULL, PRIMARY KEY (ID) ); Here's the record I'm trying to read: insert into MEMTEST (DATA) values (' { "EnterpriseMessage" : { "Body" : [ { "AccountNumber":"ABCD", "AdminCompany":null, "BrokerNumber":"WWonka" }, { "AccountNumber":"CSNE", "AdminCompany":null, "BrokerNumber":"ZWiza" } ], "Header" : { "mimetye":"application/vnd.ms-powerpoint", "destinationsystem":"ETL",

MemSql leaf down on Single server Cluster

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问题 I have a single server cluster installation of MemSQL on Ubuntu 14 LTS. I am unable to connect to memsql on port 3306 but the cluster is running on port 9000. Looks like a leaf is down. When i tried to upgrade memsql to version 4.0.1 I got this error:- Starting MemSQL Upgrade Currently on state OfflineClusterUpgrade.Init Currently on state OfflineClusterUpgrade.SnapshottingDatabases Currently on state OfflineClusterUpgrade.OfflineClusterUpgradeFail MemSQL node