April 18, 2014

Debugging problems with row based replication

MySQL 5.1 introduces row based binary logging. In fact, the default binary logging format in GA versions of MySQL 5.1 is ‘MIXED’ STATEMENT*;   The binlog_format  variable can still be changed per sessions which means it is possible that some of your binary log entries will be written in a row-based fashion instead of the […]

fadvise – may be not what you expect

I often hear suggestion to use

system call to avoid caching in OS cache. We recently made patch for

, which supposes to create archive without polluting OS cache, as like in case with backup, you do not really expect any benefits from caching. However working on the patch, I noticed, that

with […]

Too many connections? No problem!

Did that ever happen to you in production?

Just happened to one of our customers. Want to know what we did?

When should you store serialized objects in the database?

A while back Friendfeed posted a blog post explaining how they changed from storing data in MySQL columns to serializing data and just storing it inside TEXT/BLOB columns. It seems that since then, the technique has gotten more popular with Ruby gems now around to do this for you automatically.

Getting around optimizer limitations with an IN() list

There was a discussion on LinkedIn one month ago that caught my eye: Database search by “within x number of miles” radius? Anyone out there created a zipcode database and created a “search within x numer of miles” function ? Thankful for any tips you can throw my way.. J A few people commented that […]

Effect of adaptive_flushing

I recently had the chance to witness the effects of innodb_adaptive_flushing on the performance of InnoDB Plugin 1.0.5 in the wild, which Yasufumi wrote about previously here and here. The server in question was Solaris 10 with 8 disk RAID10 and 2 32GB SSDs used for ZIL and L2ARC, 72G RAM and 40G buffer pool. […]

“Shard early, shard often”

I wrote a post a while back that said why you don’t want to shard.  In that post that I tried to explain that hardware advances such as 128G of RAM being so cheap is changing the point at which you need to shard, and that the (often omitted) operational issues created by sharding can […]

Tokyo Tyrant -The Extras Part III : Write Bottleneck

This is part 3 of my Tyrant extra’s, part 1 focused on durability, part 2 focused on the perceived performance wall. #3.  Tokyo Cabinet Can have only a single writer thread, bottlenecking performance When writing an application using Tokyo Cabinet only one connection can be opened as a “writer”  while the rest are readers.  Tyrant […]

Tokyo Tyrant – The Extras Part II : The Performance Wall

Continuing my look at Tokyo Tyrant/Cabinet and addressing some of the concerns I have seen people have brought up this is post #2. #2.  As your data grows does  Tokyo Cabinet slow down? Yes your performance can degrade. One obvious performance decrease with a larger dataset  is you start to increase the likelihood that your […]

MySQL-Memcached or NOSQL Tokyo Tyrant – part 3

This is part 3 of our series.  In part 1 we talked about boosting performance with memcached on top of MySQL, in Part 2 we talked about running 100% outside the data with memcached, and now in Part 3 we are going to look at a possible solution to free you from the database.  The […]