This poll was posted last week on Arjen’s blog and is still open for a few more days to receive your vote. The comments on the original post contain some interesting considerations either way, and many in fact non-technical. Anyway, please add your vote, and optionally your thoughts to the comment thread!

Robert Treat and I had some back and forth emails a few weeks ago about explaining database replication to customers. Replication is totally cool but it is also completely confusing to a lot of people. The basic concepts are not widely understood. Plus PostgreSQL does not help by giving you a wide range of methods, often with poorly documented trade-offs.

Based on our conversation I put together a talk for PG West in Portland called Getting Smart about the New World of PostgreSQL Replication. It explains basic concepts and surveys five replication approaches. Press the title and you can possess the slides yourself.

Robert and I had talked about putting …

Ever wonder how long that MySQL statement took to run? Or what pace those scripts you run from cron take to run at night? You can change the prompt on the MySQL command-line tool to show user name, time, current database or many other useful facts.

>mysql  foo
mysql> prompt \R:\m:\s>
PROMPT set to '\R:\m:\s>'
14:11:16>SHOW TABLES;
+------+
| foo  |
| bar  |
+------+
2 rows in set (0.01 sec)

14:12:12>

I find this quiet handy in scripts that I run late at night. It is also good when running a complex statement that will consume clock time so that I can tell when it finished. Not exactly awe inspiring but a quite handy 'trick'.



Details are here half way down the page.

Welcome to the 119th edition of Log Buffer, the weekly review of database blogs.

We start in the MySQL world with some engine news. On Brian “Krow” Aker’s Idle Thoughts, Brian explains the state of engines in Drizzle, the pared-down MySQL. He begins, “So many engines, and so little to choose from. This is one of our two major decision points in Drizzle right now.” Maria, Falcon, PBXT, and InnoDB are in the dock.

Arjen Lentz asks a simple question: Would you prefer InnoDB to be the default storage engine?, also the subject of a quick …

Sequoia Capital offers insights on surviving the economic downturn. READ MORE

A lot of comments on my last blog. Here is my response

How can I get more details for each SQL statement?
The second argument to dispatch_command is a pointer to the THD structure. It contains all sorts of information. You can dig for all the info you may ever need. Only issue is that we are now dealing with the internal structures and these may change for every release. So the script will not be portable. When I get a few minutes I'd blog a sample but your millage may vary.
A better way to get these structures is using the embedded MySQL DTrace probes. These will expose the info you need. For details on the embedded DTrace probes and example scripts on how to get these details see the discussion thread on OpenSolaris DTrace Discuss Finally the tid was printed to give you some amount of isolation based on connections. Not …

As standard, MySQL allows replication from one master to multiple slaves, and that is a common scale-out scenario, but there have been a few comments recently, and some longer standing queries about having a setup that works the other way round, that is, multiple slaves replicating into a single master.

This a common enough scenario in data logging systems, where the data is collected locally and then distributed up to a central database, or in EPOS (Electronic Point of Sale) systems where you want the transactions logs from the tills logged up to the database at head office. There are many other situations where you want that merging of information.

Although MySQL doesn’t support what is called ‘multiple master, single slave’ solution, you can simulate the general approach by using a combination of replication and federated tables.

Replication allows for different table types on the master (the source of the data) …

Within the APAC region? Planning to attend foss.my (November 8-9 2008)? Why not stay a little longer, for the MySQL for Developers training course - 5 days, from 10-14 November 2008, conducted by my good friends at hSenid (MySQL partners in Malaysia). To register, or find out more, drop Ruchith a quick email at ruchith[at]hsenid[dot]com.

Read Alexis' Adoption Story and, for full details, go to our usual Questionnaire.

Hey everyone, I try to get the magazine out every three months on the 15th. Sometimes life gets in the way. Imagine that! The next issue is looking great and will be out very soon.

Not to early to start thinking about what you want in the next issue. I will be asking for article ideas very soon.

Keith