Today High Performance MySQL, Second Edition went to press. I’ve been working with the production team over the last couple of weeks, proofreading and checking the index and working with the artist who re-drew the illustrations. I spoke to the production editor this morning and she told me the schedule is for the bound-book date to be the 16th of June. The official in-stock date is June 19th. I don’t know how many copies they’re printing for the first printing.

As a consultant, I do a lot of content migrations for clients. One issue I run into quite often is the encoding of databases, tables, columns differs between source and destination. Most clients do not want me to go and change the way their encoding is to fix issues since they are too afraid about messing with production data. Of course amongst other issues, it creates weird characters for data which is copied/pasted from Microsoft Word. You see weird characters like: ’ … – “ †‘

So if you just want to replace these with appropriate symbols, you may do it with a simple sql query. Note that below queries are without where clause. You may what to test it with one of your rows before making changes to the whole table. Of course, you should always backup your data before you try this out. If you have a dev system, that is even better. I put …

On MySQL developers zone there is a quick poll on which operating system you use.

The combined results of all Linux flavors accounts for 50% of the answers so far. What surprised me is the 6% of mac OSX used as a server. My own experience with macs is just as desktop or laptop. In my very personal view, it feels like a waste to use such a beautiful thing like a Mac as a server. Linux, as Neal Stephenson put it in In The Beginning Was The Command Line is like a tank. Efficient but not appealing, compared to Macs, which are described as stylish cars.
So, if business is a battle, the Linux tank seems your …

In my post from yesterday, I ended up resorting to using multiple-column fulltext indexes to make it so I was actually using the indexes on the columns specified in the query. Well, that worked. But it also resulted in HUGE indexes!

Before change:

-rw-rw---- 1 mysql mysql 1177773692 2008-06-05 12:37 items_text.MYD
-rw-rw---- 1 mysql mysql 1136713728 2008-06-05 12:37 items_text.MYI

After adding more indexes:

-rw-rw---- 1 mysql mysql 1156516200 2008-06-04 17:14 items_text.MYD
-rw-rw---- 1 mysql mysql 1978787840 2008-06-04 17:14 items_text.MYI

Furthermore, this made the table much harder to update. Replication kept lagging last night (nagios was complaining loudly).

I've since reverted back to the way I had it, not using the index, which is the least worse of my …

1) Which operations can I perform during a table reorg?
everything except DDL and node restart
ndb does currently only allow one DDL at a time, and the reorg is a DDL
ndb does currently prevent node restart while DDL in ongoing

2) What happens to an ongoing table reorg during
2a) node failure
reorg will be completed or aborted depending on how long it has progressed
(i.e if commit has been started)
2b) cluster failure, and recovery?
reorg will be completed or aborted depending on how long it has progressed
(i.e if commit has been written)

The reorg is committed after rows have been copied, but before rows has been
deleted/cleaned up

3) How do my a) SQL b) NDBAPI applications have to be changed to cope with table reorg?

Not at all, but
- your application can "hint" incorrectly if it does not check table state …

Contrary to what I said earlier, Falcon has decided to deliberately disable statement-based replication using the same capabilities mechanism that InnoDB uses.

The reason is that isolation between concurrent transactions cannot be guaranteed, meaning that two concurrent transactions are not guaranteed to be serializable (the result of a concurrent transaction that has committed can "leak" into an ongoing transaction). Since they are not serializable, it means they cannot be written to the binary log in an order that produce the same result on the slave as on the master.

However, when using row-based replication they are serializable, because whatever values are written to the tables are also written to the binary log, so if data "leaks" into an ongoing transaction, this is what is written to the binary log as …

So, we had a cron job hanging for hours.  No idea why.  So, I started debugging.  It all came down to a call to in_array().  See, this job is importing data from a huge XML file into MySQL.  After it is done, we want to compare the data we just added/updated to the data in the table so we can deactivate any data we did not update.  We were using a mod_time field in mysql in the past.  But, that proved to be an issue when we wanted to start skipping rows from the XML that were present but unchanged.  Doing that saved a lot of MySQL writes and sped up the process.

So, anyhow, we have this huge array of ids accumulated during the import.  So, an in clause with 2 million parts would suck.  So, we suck back all the ids in the database that exist and stick that into an array.  We then compared the two arrays by looping one array and using in_array() to check if the value was in the …

Along with evolving and documenting interface for writing Workbench plugins we think about community site which will make sharing and usage of plugins within community extremely easy. Conceptually it will be close to addons.mozilla.org. Users will be able to explore directory of published addons, read description and comments on them, quickly install and rate whatever they consider necessary. To install selected addon user will have just to drag’n'drop corresponding link to Workbench, and the rest will be done by Workbench. Every addon will be supplied with manifest file describing its version, dependencies on other addons (if any), files to be installed, menu items to be added, etc. Addon has wide definition, it could be a plugin (dynamic library), set of demo models, documentation, SQL scripts, whatever. Now things are nearly in the middle of development stage. If you have ideas on how to improve the process of …

Please, enlighten me on what being in a separate suite means! I see there is a suite directory in mysql-test. Will the suites be run by default when I use 'mtr' to run tests? Or do I have to add them manually?
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The number of tests we have for MySQL Server are constantly growing. There is a need to group them in different ways so we can select what and where to run. We do this by using suites, either the default suite that we call "main" in mysql-test/t or one of the subdirs of mysql-test/suite.

As each test becomes more advanced it's also necessary to use different configurations for a particular test or suite. For example all the replication tests in suite/rpl need to be run with the server started in three different ways(three different configurations) to get full coverage. To avoid that the individual developer or the "one" running tests have to remember different …

Hi Magnus, is there a way to concatenate strings in a mysqltest?
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Yes, you can "easily" create more dynamic strings using let and a while loop. For example like this:

let $c= 254;
let $str= t255;

while ($c)
{
     let $str= t$c,$str;
     dec $c;
 }
 echo $str;

This will printout t1, t2, t3, ... t255.


You can then use the $str variable in an eval
to CREATE TABLE, VIEW or SELECT

eval CREATE TABLE t0 (a INT) ENGINE=MERGE UNION($str);