Following on from our earlier announcement, Paul McCullagh has responded with the answers to your questions - as well as a few I gathered from other Percona folks, and attendees of OpenSQL Camp. Thank you Paul!

What’s the "ideal" use case for the PBXT engine, and how does it compare in performance?  When would I use PBXT instead of a storage engine like MyISAM, InnoDB or XtraDB?

Unfortunately it is not possible to point to a specific category of applications and say, "PBXT will be better here, so try it".  PBXT is a general purpose transactional storage engine, designed to perform well on a broad range of tasks, much like InnoDB.  However, PBXT's log-based architecture makes performance characteristics different to both MyISAM and InnoDB/XtraDB. Tests show that PBXT's performance is similar to InnoDB but, depending on your database designed and the application, it can be faster.

PBXT is a …

Here’s a rundown of Thursday (day 3) of the MySQL Conference and Expo. This day’s sessions were much more interesting to me than Wednesday’s, and in fact I wanted to go to several of them in a single time slot a couple of times.

Inside the PBXT Storage Engine

This session was, as it sounds, a look at the internals of PBXT, a transactional storage engine for MySQL that has some interesting design techniques. I had been looking forward to this session for a while, and Paul McCullagh’s nice explanations with clear diagrams were a welcome aid to understanding how PBXT works. Unlike some of the other storage engines, PBXT is being developed in full daylight, with an emphasis on community involvement and input. (Indeed, I may be contributing to it myself, in order to make its monitoring and tuning capabilities second to none).

PBXT has not only a unique design, but a …

• Paul McCullagh presents
• BLOB
  • invented by Jim Starkey
  • Basic Large OBject
  • Binary Large OBject
  • photos, films, mp4 files, pdfs, etc
• how MySQL handles BLOBs
  • mysql client send buffer -> receive buffer on the server (max_allowed_packet)
  • streaming a BLOB
    • continuous data stream
    • stream BLOB data directly in and out of the database
    • store BLOBs of any size (>4GB) in the database
    • create a scalable back-end that can handle any throughput and storage requirements. Wouldn't need to know in advance how big the database will get
    • provide an open system that can be used by all engines
    • provide extensions for …

Today is the first day at the conference (aside from the tutorials, which were yesterday). Here’s what I went to:

New Subquery Optimizations in 6.0

By Sergey Petrunia. This was a similar session to one I went to last year. MySQL has a few cases where subqueries are badly optimized, and this session went into the details of how this is being addressed in MySQL 6.0. There are several new optimization techniques for all types of subqueries, such as inside-out subqueries, materialization, and converting to joins. The optimizations apply to scalar subqueries and subqueries in the FROM clause. Performance results are very good, depending on which data you choose to illustrate. The overall point is that the worst-case subquery nastiness should be resolved. I’m speaking of WHERE NOT IN(SELECT…) and friends. It remains to be seen how this shakes out as 6.0 matures, and what edge cases will pop up.

The Lost Art Of the Self …

In the first two articles in this series, I discussed archiving basics, relationships and dependencies, and specific archiving techniques for online transaction processing (OLTP) database servers. This article covers how to move the data from the OLTP source to the archive destination, what the archive destination might look like, and how to un-archive data. If you can un-archive easily and reliably, a whole new world of possibilities opens up.