replication

一、mysql cluster 结构 ： sql + data + mgm节点 原理 ： 集群由3个概念 1，sql节点 sql node 2，数据节点 data node 3，管理节点 ndb managerment s ql语句发送 sql节点 ， sql节点 发往 数据节点， 再由 管理节点 完成数据节点的之间的同步。 集群技术相对复杂，至少有3种节点,4台服务器才能完成。 二、mysql replication 结构 ： master + slave 1、主从复制 master负责写，slave负责读，解决了数据库瓶颈问题 原理 ： 1，主服务器运行语句，都产生一个二进制日志 binlog 2，从服务器不断读取主服务器的binlog 3，从主服务读取到的binlog,转换为自身可执行的relaylog 4，执行relaylog 实现步骤 ： 1，首先确保主服务器打开二进制日志功能 主服务器一旦有数据变化，立即产生二进制日志 2，从服务器也需要开启二进制日志和relay日志功能 这样可以从主服务器读取binlog，并产生relaylog 3，在主服务器建立一个从服务器的账号,并授予数得上权限 4，指定从服务对应的主服务器,开启从服务器 具体实施 ： 虚拟机下有两台CentOS-6.7，IP为192.168.1.67(master)和192.168.1.83(slave) 1

I want to replicate some of data that exists in my database. I want to replicate specified data. Is there a solution? USe Replication Row Filters : Using static row filters , you can choose a subset of rows to be published. All Subscribers to a filtered publication receive the same subset of rows for the filtered table alt text http://i.msdn.microsoft.com/ms151775.e4e1c995-fe81-4c05-b661-39087b323161(en-us,SQL.100).gif See also: How to: Define and Modify a Static Row Filter (SQL Server Management Studio) How to: Define and Modify a Parameterized Row Filter for a Merge Article (SQL Server

I have 2 slaves replicating from a master that has a 17GB index. I synced both slaves to this, AFTER which I set the poll interval to 60 seconds. One of the slaves tries to download the entire 17GB index even if only a tiny portion of it has changed. The other does not do this - it is able to get the latest index without this brute force sync. The redundant downloading causes me to exceed my disk space quota because it takes more than 60 seconds to download 17GB and solr kicks off a 2nd sync into yet another temporary directory. Does anyone have any tips on how to debug this? I can only see

I'm carrying some experiments on the performance of Cassandra. I have a single cluster of 8 nodes. While increasing the replication factor from 1 to 8, i noticed that the overall throughput decreases. I'm using consistency level ONE for both reads and writes. I found that these are not the expected results. Anyone explain why this is happening? This should be completely expected. Consistency level one will keep the performance of your reads as basically the same (if not improved since their are more possible machines to serve each read) but your writes will be doing significantly more work.

Problem I'm building a postgres database for a few hundred thousand products. I will set-up an index (Solr or maybe ElasticSearch) to improve query times for complex search queries. The point now is how to let the index synchronized with the database? In the past I had a kind of application that polled the database periodically to check for updates that should be done, but I would have an outdated index state time (from the database update to the index update pull). I would prefer a solution in which the database would notify my application (java application) that something has been changed

The same question is repeated again and again and i am another one repeating this question . I have already set up my mysql server . Its location is C:\Program Files\MySQL\MySQL Server 5.5 but i am not able to find the my.ini file inside the above path . When i type the command c:>mysql --help The output looks like Default options are read from the following files in the given order: C:\Windows\my.ini C:\Windows\my.cnf C:\my.ini C:\my.cnf C:\Program Files\MySQL\M ySQL Server 5.5\my.ini C:\Program Files\MySQL\MySQL Server 5.5\my.cnf The following groups are read: mysql client But when I opened

I encountered the following warning after converting a mongodb replica set to a stand alone server. I did rs.remove('host') and removed the replSet arguments when starting the mongo db. [root@sam ~]# mongo MongoDB shell version: 2.4.3 connecting to: test Server has startup warnings: Tue Jul 9 17:18:46.076 [initandlisten] Tue Jul 9 17:18:46.076 [initandlisten] ** WARNING: mongod started without --replSet yet 1 documents are present in local.system.replset Tue Jul 9 17:18:46.077 [initandlisten] ** Restart with --replSet unless you are doing maintenance and no other clients are connected. Tue Jul