You might find yourself running into trouble when following the otherwise very well-written instructions on how to install a binary distribution of MySQL 5.1 on (K)Ubuntu.

If you get loads of errors while attempting to run

Code:

scripts/mysql_install_db

, you should instead run

scripts/mysql_install_db --user=mysql --no-defaults

Rant mode on…

While searching the bugs system before reporting this as a new bug, I came across this entry, and noticed that the severity of the bug is set to “S3 (non-critical)”.

How in the world can instructions that specifically guide the user into creating an admin account with no …

Preparing to move I'm selling stuff on GumTree which is UK based clone of Craigslist offering similar functionality but with Ads

Similarly to Craigslist GumTree is powered by MySQL but unlike craigslist it looks like they are shy in tuning their MySQL Full Text Search index configuration and setting proper ft_min_word_len value. Searching for Audi A6 will give you a lot of Audi with different model numbers. Searching just for A6 gives no results at …

I just read the post from Mark regarding some questions he had about the Falcon engine. One of the points that made me jump is the following:

Row-level replication (instead of statement-based replication) is required when replicating Falcon objects.

This might be enough to keep me from upgrading, but I am not sure if this is limited to Falcon. Will future MySQL releases require the use of row based replication? Having SQL statements in the binlog is invaluable to me and I am not willing to give that up.

Now, seriously, it is not trivial to disable statement-based replication for any engine so it is basically always on; whether it works as expected is a different story. So, in short: there is nothing specifically done to disable statement-based replication for the Falcon engine. It is just not …

From time to time it is necessary to get a bigger picture of your project in terms of size, test coverage, code vs. comments ratio and others (aka metrics). While it is quite difficult to find a good (and free) code coverage tool for C++ there is already a very nice tool package called DPack, which is not only freely available but also gives us some very useful additions in our IDE. One of those features is code statistics.

(more…)

This is the english translation of another article in my german language blog.

How are transactions organized physically

When InnoDB creates a new transaction it is not yet committed. The database has not yet made any promises to the application and so we do not really have to make anything persistent so far.

To be fast InnoDB tries to assemble the transaction in a memory buffer, the innodb_log_buffer. It should be sufficiently large that you actually can assemble such a transaction in memory without needing to write it out in part into the redo log. A size of 1M to 8M is normal.

Once a transaction is to be committed InnoDB has to read the page from disk which contains the image of the row that is being changed. It then has to actually make that change in memory. The changed page is …

This is an english translation of the second part of an article in my german language blog.

Transactions - An InnoDB tutorial

InnoDB does transactions. Meaning: It collects statements working on InnoDB tables and applies them on COMMIT to all tables "at once". Either all of these statements inside one transaction succeed ("commit") or all of them fail ("rollback"), changing nothing.

By default, the database is in AUTOCOMMIT mode. Meaning: The server sees a virtual COMMIT command after each statement. You can disable autocommit completely, or you are starting an explicit transaction inside autocommit using the BEGIN statement.

Continue reading "Transactions - An InnoDB …

MySQL offers a variety of storage engines giving you a lot of flexibility in managing your storage and data access needs. Still I encounter customers who are not using this flexibility when they should, because they lack information about the advantages of Non-MyISAM storage engines or which are using storage engines like InnoDB as if they were using MyISAM.

This is the introductory article in a series of texts that will hopefully once become an InnoDB tutorial. A german version of this article is available in my german language blog.

An InnoDB Tutorial

The InnoDB storage engine is an engine that can be operated ACID compliant, does transactions and foreign key constraints. It is useful for all applications that do online transaction processing or have a high rate of concurrent write accesses for other …

A

I need to compile something and use the MySQL C++ library. I have mysql and mysql++ already compiled, I won’t go over how to do that now.

I added the following code to the top of my source:


#include <mysql++.h>


I got an error

/Users/jhaddad/dev/search_engine/main.cpp:4:21: error: mysql++.h: No such file or directory

Not cool.

How to fix:

In XCode, open up the project settings (under the project menu). Go down to search paths, and you can change your Header search paths to the correct locations where you installed whatever you’re looking for. In this case, mine was /usr/local/includes and /usr/local/mysql/

Next time you try to recompile, you’ll get a different error, this time it should be during Linking. Might look something like the below.

“mysqlpp::Query::store(mysqlpp::SQLQueryParms&)”, referenced from:

…

We're heading into February and that means there's only a few weeks left until the MySQL Conference & Expo early registration expires.  This year's conference promises to be our biggest and best ever.  I suspect that a lot of the hot tutorials on performance tuning and new features will sell out early.  There will be sessions on our various storage engines including InnoDB, Cluster, Falcon and Maria -- a new "MyISAM …