Monthly Archives: February 2013

Install MongoDB 2.0.6 on Fedora 17/16, CentOS/Red Hat (RHEL) 6.3/5.8

The first part of this article is copied from since we will not reinvent the wheels 🙂 What is MongoDB? MongoDB (from “humongous”) is a scalable, high-performance, open source, schema-free, document-oriented database. Written in C++. MongoDB bridges the gap between key-value stores (which are fast and highly scalable) and traditional RDBMS […]

Using MySQL as a NoSQL – A story for exceeding 750,000 qps on a commodity server

This article describe an example of using MySQL as a NoSQL in which the application can exceed 750,000 qps on a commodity server. This is originated from UPDATE: Oracle officially released memcached daemon plugin that talks with InnoDB. I’m glad to see that NoSQL+MySQL has become an official solution. It’s still preview release […]

NoSQL Data Modeling Techniques

NoSQL databases are often compared by various non-functional criteria, such as scalability, performance, and consistency. This aspect of NoSQL is well-studied both in practice and theory because specific non-functional properties are often the main justification for NoSQL usage and fundamental results on distributed systems like the CAP theorem apply well to NoSQL systems. […]

MySQL Replication :: Recovering from corrupted relay logs

Recently, due to a unknown problem, mysql replication in our server was stopped. Checking the log, we found the following error 130225 21:17:32 [ERROR] Error in Log_event::read_log_event(): ‘read error’, data_len: 261, event_type: 2 130225 21:17:32 [ERROR] Error reading relay log event: slave SQL thread aborted because of I/O error 130225 […]

Host ‘yourhost’ is blocked because of many connection errors; unblock with ‘mysqladmin flush-hosts’

When there are many errors when connecting to a mysql server, the following error might appear and the application cannot connect to the db server any more: Host ‘yourhost’ is blocked because of many connection errors; unblock with ‘mysqladmin flush-hosts’ The above error might appear when the application server and […]