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Displaying posts with tag: network (reset)
Network Traffic Analyzer with RaspberryPI

Motivation Melbourne just won the “most liveable city 2016”, the 5th time in a row. That’s awesome, but it comes with a price, and the one you’d think of: internet here sucks! Sounds weird, isn’t it? Well, one of the reasons Melbourne is such a great city, is it’s size, the amount of people in [...]


we use tcpcopy to make real traffic on our core systems. Many problems will be found in advance if we enlarge queries several times.


linux memory management for servers

We’ve been learning for many years how to run Linux for databases, but over time we realized that many of our lessons learned apply to many other server workloads. Generally, server process will have to interact with network clients, access memory, do some storage operations and do some processing work – all under supervision of the kernel.

Unfortunately, from what I learned, there’re various problems in pretty much every area of server operation. By keeping the operational knowledge in narrow camps we did not help others. Finding out about these problems requires quite intimate understanding of how things work and slightly more than beginner kernel knowledge.

Many different choices could be made by doing empiric tests, sometimes with outcomes that guide or misguide direction for many years. In our work we try to understand the reasons behind differences that we observe in random poking at a problem.

In order …

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MySQL - basic network security

Having secured our MySQL server and created a personal account to allow for remote administration, we can take one step further on blocking unwanted access to our database server. For this example, we'll continue to use the Ubuntu 14.04.2 LTS Server installed and configured on the previous posts. After booting up the server, running a network check for connections, lists our server listening on

How to configure Tcpdump system

MySQL Tcpdump system : use percona-toolkit to analyze network packages

We can identify problem SQLs with high execution frequency.

With DBMON system and AWR system we can find problem SQLs in a special time (high frequency, occurs over a period of time)

View this PDF:

Troubleshooting Database Network Problems Using tshark

Today, one of the MySQL database server response time has been increased within the pool of servers and noticed it was returning the query in 0.20 secs (randomly) as opposed[...]

Pictures from Pedro’s Dinner 2012

Pedro’s dinner was full! I didn’t count, but we had 9 tables of 8-10 people or so – dare I say almost 100 people? Lots of beer, margaritas, and good conversations! Here are a few pictures from the event:

MySQL Conference 2012 Day 0

Wow! A lot has changed since the last MySQL conference I blogged about in 2007.

MySQL has been acquired twice: once as MySQL by Sun and the second time around bundled with Sun when Oracle bought Sun. The conference is no longer organized by O’Reilly but by Percona. And the MySQL database itself has changed — we were talking about new features in MySQL 5.1, which wasn’t released yet, along with Falcon (where did it go?). 5.1 has long since been released as has 5.5, and we’re now talking about 5.6 instead of 6.0. There was no “Cloud” on the horizon, nor was there MariaDB, XtraDB, Drizzle, Schooner, or any of the other offshoots of MySQL, all of which are creating a new buzz around the product.

Yet, one thing remains constant: the vibrant community around MySQL. In spite of all the changes in technology, ownership, versions, …

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mysql jdbc connector autoReconnect=true

What makes you think jdbc autoreconnect is needed?
Application is idle for long periods at a time?
Wait_timeout too short?
Network failure or glitches?

Some good suggestions form Mark Matthews - Bug #5020

Having encountered the problem again myself today, trying to make jdbc for mysql reconnect any terminated connections using autoreconnect=true I figured out a way to work it out from the pooling side.

Introduction to the problem:

On the mysql side wait_timeout is set to default 8hrs and any connections idle for longer than that were beomg terminated despite setting the connection string to: url=jdbc:mysql://localhost:3306/dbname?autoReconnect=true. The application was thence throwing an exception.

The solution was to introduce a ping from the pooler which for “Ibatis”, the pooler technology used …

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Ravelry Runs On – 2010

I guess that it’s time for the 3rd annual “Ravelry Runs On” roundup. The last two were in March 2008 and March 2009.

This year, our traffic increased by 50% to 5,000,000 page views and 15 million Rails requests per day. We made very few changes to our architecture in 2009 but we did add a new master database server after our working set of data outgrew our memory and IO capacity.

This summary is more detailed then the last two and I’ve broken it up into rough sections.

Physical Network

We own our own servers and colocate then in a datacenter here in Boston. The datacenter provides us with a cooled half cabinet, redundant power, and a blend of premium (Internap, Savvis) bandwidth. We do the rest.

I use …

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