replication

In an application which embeds SQLite3 and uses an in-memory database, is it possible to replicate the database between two running instances of the application? I could do this by hand with a homebrew protocol duplicating all my DB accesses, but it seems like something that should be done inside the DB layer. Brute force approach: Send it the ".dump" command to create a text representation of the data. Read that data in into the second database. Not sure you can use that. If you need a fine grained update (sending a copy of each upto the other copy), have a look at sqlite3_update_hook But how

Say you have 2 database servers, one database is the 'master' database where all write operations are performed, it is treated as the 'real/original' database. The other server's database is to be a mirror copy of the master database (slave?), which will be used for read only operations for a certain part of the application. How do you go about setting up a slave database that mirrors the data on the master database? From what I understand, the slave/readonly database is to use the master db's transaction log file to mirror the data correct? What options do I have in terms of how often the

Assume we setup a MongoDB replication without arbiter, If the primary is unavailable, the replica set will elect a secondary to be primary. So I think it's kind of implicit arbiter, since the replica will elect a primary automatically. So I am wondering why do we need a dedicated arbiter node? Thanks! I created a spreadsheet to better illustrate the effect of Arbiter nodes in a Replica Set. It basically comes down to these points: With an RS of 2 data nodes , losing 1 server brings you below your voting minimum (which is "greater than N/2"). An arbiter solves this. With an RS of even numbered

It is connected to BI and merging of data from different data sources and would make that process more smooth. And is there an optimal migration strategy from a database without Guids to a version with Guids without information losses? Edited after reading Frans Bouma's answer, since my answer has been accepted and therefore moved to the top. Thanks, Frans. GUIDs do make a good unique value, however due to their complex nature they're not really human-readable, which can make support difficult. If you're going to use GUIDs you might want to consider doing some performance analysis on bulk data

I want to setup replication between SQL Server and MySQL, in which SQL Server is the primary database server and MySQL is the slave server (on linux). Is there a way to setup such scenario? Help me . takemoa My answer might be coming too late, but still for future reference ... You can use one of the heterogeneous replication solutions like SymmetricDS: http://www.symmetricds.org/ . It can replicate data between any SQL database to any SQL database, altough the overhead is higher than using a native replication solution. of course you can replicate MSSQL database to MYSQL By using Linked

概述 Redis 支持简单且易用的主从复制（master-slave replication）功能， 该功能可以让从服务器(slave server)成为主服务器(master server)的精确复制品。 以下是关于 Redis 复制功能的几个重要方面： Redis 使用异步复制。 从 Redis 2.8 开始， 从服务器会以每秒一次的频率向主服务器报告复制流（replication stream）的处理进度。 一个主服务器可以有多个从服务器。 不仅主服务器可以有从服务器， 从服务器也可以有自己的从服务器， 多个从服务器之间可以构成一个图状结构。 复制功能不会阻塞主服务器： 即使有一个或多个从服务器正在进行初次同步， 主服务器也可以继续处理命令请求。 复制功能也不会阻塞从服务器： 只要在 redis.conf 文件中进行了相应的设置， 即使从服务器正在进行初次同步， 服务器也可以使用旧版本的数据集来处理命令查询。 不过， 在从服务器删除旧版本数据集并载入新版本数据集的那段时间内， 连接请求会被阻塞。 你还可以配置从服务器， 让它在与主服务器之间的连接断开时， 向客户端发送一个错误。 复制功能可以单纯地用于数据冗余（data redundancy）， 也可以通过让多个从服务器处理只读命令请求来提升扩展性（scalability）： 比如说， 繁重的 SORT