In a previous post I mentioned about patches needed to accomadate the new DST changes for Sql Server. (I know, this is one of Dannyman’s favorite subjects ;))

For MySQL, obviously you need to patch the host server first. Then you need to find out if MySQL needs separate work. Here is a note I gathered. Let me know if I am wrong on this or if there is a better way.

1. Get into mysql and do \s to find out the version of your MySQL.

If it is prior to 4.1.3, don’t worry about it.

Else

2. Do select @@global.time_zone;

If the result is SYSTEM, don’t worry about it.

Else

You need to load time zone info, usually at /usr/share/zoneinfo into your mysql database, by running something like:

# …

Here is MySQL's nested outer joins optimization cheat sheet:

• Conversions:
  
  • RIGHT JOIN is converted to LEFT JOIN. FULL JOIN is not supported.
  • Outer joins are converted to inner joins when possible
• Constraints on join order:
  • "Outer tables go first"
  • "No interleaving"
• Table access rules:
  • "Inner" table access methods are constructed from parts of the ON condition. WHERE condition can't be used to construct table accesses.
  • Parts of ON condition are checked as soon as possible
  • Parts of the WHERE condition
    - are not checked until we've found a row combination that matches the ON clause
    - are checked as soon as possible after that.

Or, in more detail:

…

When you ask someone how to optimize SQL queries you will always get the answer

• enable the slow query log
• set the long-query-time to 1-2 seconds
• enable the logging of query which aren't using an index
• run EXPLAIN on the queries that are shown and optimize them with proper indexes

But how to understand what the EXPLAIN is telling you ?

I picked a query from the ORDER BY RAND article as they became interesting enough to show the different aspects of of a query. They contain:

• Sub-Queries
• Unions
• Special cases
• JOINs
• ORDER BY + LIMIT

If you want to understand how this query was developed, check the original article about …

I suppose it was no surprise that Marc Fleury, founder of JBoss would eventually leave Red Hat after selling his company last year.  Marc was a classic enterpreneur full of enthusiasm, bravado and, yes, ego.  But as they say, it ain't braggin' if you done it.  He built a successful open source project that changed the game for J2EE app servers and turned it into a rapidly growing software organization, now solidly part of Red Hat.

Above all else, Marc Fleury is passionate.  Here's a former french paratrooper with a PhD who in the early days created a rival JBossOne party in the shadow of Sun's JavaOne. On a bet he ran a marathon in China with …

In about 4.5hrs, I’ll be in a cab to the airport. At about lunchtime (1:30pm or so) London time, I’ll be in London. I’ll be there for a few days - until the 27th. If you’re around London or can make it, it’d be cool to hang. I plan to be a bit of a tourist here and there as I haven’t seen heaps of London and I do hear it’s nice :)

After that, I’ll be in Stockholm for about three weeks (I leave on the 19th… as it’s currently planned). So if you’re around, give me a yell!

My cell (mobile) number is pretty easy to find (hint: google my name along with my employer and look for a post on a mailing list… my work email sig has my phone number).

I’m in Stockholm for work, I’m going to be working in the office (which will be the longest amount of time I’ve gone to work in an office in over 2 years).

MySQL releases carrier grade edition database…OpenLogic and Covalent partner on Apache support…Fonality reaches out to the SMB telephony market…and more…

New ‘MySQL Cluster Carrier Grade Edition’ - Reduces Cost & Complexity of Telecom Subscriber Databases, MySQL AB (Press Release)

OpenLogic Enhances Support For Leading Apache Server Products, OpenLogic / Covalent (Press Release)

Pramati and Covalent Announce Strategic Alliance for Product and Technology Services, Covalent / Pramati (Press Release)

Fonality Breaks Price Barriers, Making Call Centers Affordable …

One of my current interests is looking for bottlenecks in MySQL with
regards to the use of Multiple CPU usage.

I noticed Tim's comments yesterday on this topic:
http://radar.oreilly.com/archives/2007/02/a_fast_waitfree_1.html

What I see right now is that for the first time in years commodity
scaling with multiple CPU's is becoming a reality. What does this mean?

For years we have been scaling out, adding more hosts. Every hosts
increases the total cost of ownership. You can do this with two
processor hosts, but this is not all that interesting. Scaling for
two processors is quite easy, its when you get more then two that the
problem becomes interesting (Slashdot has had four processor machines
for its databases since 2001, but they were 32bit so the …

It's no secret to anyone that Microsoft caters to developers while Apple is faithful to end-users.  I happen to like Apple's approach since, as a developer, I actually do qualify as a user.  Microsoft should really be concerned since I don't think I would find too many people that would disagree when I say that if the market shares were even, Apple would seriously be in the driver seat.  I use Windows because that's where my money is made and where most of the applications I use exist.  Here is just one example where Microsoft unnecessarily makes things complicated.  Consider this screenshot of my installed apps (I'm using Vista x64).

Now, why do I have separate items listed for SQL Server VSS write, and setup support files, and native …

When you ask someone how to optimize SQL queries you will always get the answer

• enable the slow query log
• set the long-query-time to 1-2 seconds
• enable the logging of query which aren't using an index
• run EXPLAIN on the queries that are shown and optimize them with proper indexes

But how to understand what the EXPLAIN is telling you ?

I picked a query from the ORDER BY RAND article as they became interesting enough to show the different aspects of of a query. They contain:

• Sub-Queries
• Unions
• Special cases
• JOINs
• ORDER BY + LIMIT

If you want to understand how this query was developed, check the original article …

** This is an editied “re-post” of an item i wrote about a year ago. **

MySQL V5.0 has been out for a while; the current production community version is 5.0.27.

With version 5, MySQL has addressed most of the major objections people have that MySQL is not a “real” database. With support for triggers, stored procedures, views and XA transactions, I think MySQL has a feature set that will enable people to easily migrate to MySQL. At this point in time, InnoDB is the only storage engine choice for applications that require transactions, and this is still a reasonable choice in most cases.

The only open question for MySQL A.B. is resolution of the problems created by Oracle’s acquisition of Innobase Oy, the developers of the InnoDB storage engine. I previously wrote a post about the Oracle Innobase issues, the summary is that Oracle’s acquisition of Innobase Oy is a problem not because of the storage engine, but …