So, I recently ran into one of those situations where a customer complains that his MySQL database is slow, and “it worked great until about two weeks ago”. The first thing I look at in these situations is not the queries or any code, but the indexes. Once I determined that the indexes were almost nonsensical, I had a look at the queries themselves, which proved that the indexes were, in fact, nonsensical. Running the queries as written in the code, from a mysql shell, with EXPLAIN, I was able to further confirm that the indexes (most of them, anyway) were never used.

Easy right? Just reindex the table!

NOTE: I’m going to skip the talk about all of the database design issues on this gig and just go straight to solving the immediate problem at hand. Just know that I had nothing to do with the design.

But, supposing this table has 15 million rows and is running on a machine with 2GB of RAM and only …

Background Knowledge

Since MySQL v4.1 timestamp and datetime data types are formatted “YYYY-MM-DD HH:MM:SS”. Prior to MySQL v4.1 the timestamp was formatted as YYYYMMDDHHMMSS” and datetime formatted as “YYYY-MM-DD HH:MM:SS”. Refer to MySQL Reference Manual for further details.

The Unix timestamp differs from MySQL. Unix’s timestamp is a integer value of seconds since January 1, 1970. For further explanation of Unix timestamps refer to Wikiepedia or UnixTimestamp.com.

Solutions

In MySQL you can use Unix_Timestamp() function.

Query Example: SELECT …

First, AddThis.com (where I was the director of IT) and Clearspring have merged! A side effect of that is that I’m now (happily, on purpose, by choice) a full-time consultant! I’ll have a web site up soonish. Until then, check back here for updates. If you’re a tech firm who needs help, and don’t mind remote workers, send mail to bkjones at Google’s mail service (.com).

Some folks thought I’d passed away due to the uncharacteristic lull in posting frequency on this blog. I’m very much alive — but working for a startup and maintaining a consulting business simultaneously is hard, especially when two large projects fall into your lap at the same time. So what have I been up to?

Well, as part of the now-public merger between the company I worked for and the new company, …

At OOW, I ran into Stephen Feuerstein after seeing him demonstrate Quest Software's "Quest Code Tester" product. Considering how I might use a product like that for testing web-based applications, I suggested a couple of enhancements.The biggest, most important procedures that I test in PL/SQL are those that generate entire web pages. For that kind of testing, you can't look at whether data has

Here's the HP Oracle Database Machine talked about in Larry's keynote. On the way out, some audience members said they were drooling over it. I don't know if that's a good idea; didn't see anything about moisture resistance in the tech specs.I noticed that the box was about the same height as Larry. In the same way we talk about pizza boxes, 5U vs. 10U servers, etc., will we one day measure the

Its been a while I wrote anything on MySQL and/or Database related things as I was on a long two month vacation and immediately had a job change.

Today I was playing a bit in trying to setup up the ZRM community backup on Cent OS 5 to have a incremental backup mechanism; to see how it works as I never had a chance to use it so far. In the process, I could not find a single source of document which explains the basic steps needed on first-hand setup (or my search did not yield the right docs), so thought of writing and noting it down myself for any future reference. More or less, the instructions should be same for any Linux favor.

Here are the steps:

• First install perl-DBI and perl-XML-Parser modules

  sudo yum install perl-DBI perl-XML-Parser

  …

Drizzle TalkView SlideShare presentation


Drizzle talk for MySQL Developer's Meeting.


SlideShare Link

Say you want to randomly select your employee of the month, but not so randomly, better, you'd like to give your best employees a bigger chance to be selected based on their rating.This is just an example, you could be randomly displaying ads from your customers, but giving an higher chance to be displayed to those who are paying more, there can be a million other example, but I hope you got the

Users, in the context of databases, especially open ones, means developers. Do you feel like hacking some database project? If your database of choice is open (MySQL, PostgreSQL, JavaDB, SQLite, Firebird), you may give the OpenSQLCamp a try!

Well, I have started formatting the results from the survey. This will take a little while as the survey software doesn't make it easy to download and clean it up (without paying for a subscription). As soon as the data is cleaned up I will post the entire data set and a link for everyone to download.

However, while I work on the data, I will provide some summary results. Here is a list of countries who had respondents. If a country is not listed, it had 0 responses/