I’ve talked to several people that have questions about how alter table works under the hood. They want to know how it handles locking tables why they can sometimes use a table during alter table and other times they can’t. Also why it’s so slow

First let’s look at the basic process alter table typically goes through.

1. If a transaction is open on this thread, commit it.
2. Acquire a read lock for the table.
3. Make a temporary table with new structure
4. Copy the old table to the temporary table row by row changing the structure of the rows on the fly.
5. Rename the original table out of the way
6. Rename the temporary table to the original table name.
7. Drop the original table.
8. Release the read lock.

The slowest part of the process is copying rows from the original table to the temporary table. For large tables this can take minutes …

Yes, I know there are a lot of software development "top n" lists out there, and many dealing with writing "-[i/a]ble" software (extensible, maintainable, saleable, etc), but personally I wanted to get these concepts that have been rattling around in my brain for sometime down somewhere and hopefully start a discussion around them. Even though this isn't a wiki, I'll probably end up treating this like a living document myself.

For a long time (in software years), I've been maintaining the code base for the JDBC driver for MySQL. I also work very closely with the support team on various connectivity-related issues (JDBC, ODBC, ADO.Net, P-this-or-that, etc.) that our customers have, and have had the (mis)fortune of debugging all kinds of problems in various stacks over the years.

Sometimes we (MySQL) make debugging more of a problem than it needs to be, and sometimes it's just inherent problems in the "stack". Given that I …

Yes, I know there are a lot of software development "top n" lists out there, and many dealing with writing "-[i/a]ble" software (extensible, maintainable, saleable, etc), but personally I wanted to get these concepts that have been rattling around in my brain for sometime down somewhere and hopefully start a discussion around them. Even though this isn't a wiki, I'll probably end up treating this like a living document myself.

For a long time (in software years), I've been maintaining the code base for the JDBC driver for MySQL. I also work very closely with the support team on various connectivity-related issues (JDBC, ODBC, ADO.Net, P-this-or-that, etc.) that our customers have, and have had the (mis)fortune of debugging all kinds of problems in various stacks over the years.

Sometimes we (MySQL) make debugging more of a problem than it needs to be, and sometimes it's just inherent problems in the "stack". Given that I …

Yes, I know there are a lot of software development "top n" lists out there, and many dealing with writing "-[i/a]ble" software (extensible, maintainable, saleable, etc), but personally I wanted to get these concepts that have been rattling around in my brain for sometime down somewhere and hopefully start a discussion around them. Even though this isn't a wiki, I'll probably end up treating this like a living document myself.

For a long time (in software years), I've been maintaining the code base for the JDBC driver for MySQL. I also work very closely with the support team on various connectivity-related issues (JDBC, ODBC, ADO.Net, P-this-or-that, etc.) that our customers have, and have had the (mis)fortune of debugging all kinds of problems in various stacks over the years.

Sometimes we (MySQL) make debugging more of a problem than it needs to be, and sometimes it's just inherent problems in the "stack". Given that I …

this time it only took two months since the last release ? mysql connector/odbc 3.51.15 is now available. there aren?t a lot of bugs fixed in this release, compared to the 150 or so open bugs, but it is nice when you get to close a bug that is nearly three years old.

i?m not sure when the next release will happen, but i already have one patch pending.

By Mike Hendrickson

Tim has asked me to take over writing the quarterly report on the state of the computer book market.

As described in the post Computer Book Sales as a Technology Trend Indicator, our research group has built a MySQL datamart containing Bookscan's weekly top 10,000 titles sold. Bookscan measures actual cash register sales in bookstores to you, the individuals purchasing and reading the books. Retailers such as Borders, Barnes & Noble, and Amazon make up the lion's share of these sales.

Book Market Performance

Here's the year-on-year trend for the entire computer book market since 2003, when we first …

It is a good practice to check the integrity of your backups from time to time. You don't want something like this happening to you :)

time gunzip  -f -v entrieva/db4/guestbook_M-070507.tar.gz
entrieva/db4/guestbook_M-070507.tar.gz:
gunzip: entrieva/db4/guestbook_M-070507.tar.gz: unexpected end of file

real    67m56.782s
user    48m40.006s
sys     14m14.584s

Earlier, I blogged about how to install Solaris 10 on Mac book using Parallels. This post contains links to screen casts about installing Open Solaris on a laptop as dual boot.

• Introduction
• Backing up disk
• Partitioning the disk
• Solaris Express Developer edition installation
• …

Reading Linux failing to boot screen on the plane I remembered I saw something similar in my flight to the MySQL Users Conference. It wasn’t so critical, but my entertainment screen got an unexpected reboot and I could see the tux logo and the console for like 2 secons while booting. This was with Northwest Airlines.

So, who said Linux had problems with video?

I left the last post in this series at the point of running make for the bitkeeper client. If you have been following the posts and tried to do that, you will be greeted with the following errors:

bash-3.00# make
cc -O2 -Wall -Wno-parentheses    bkf.c   -o bkf
cc: Warning: option -2 passed to ld
cc: illegal option -Wall
make: *** [bkf] Error 1

The first line shows the compiler options being used followed by a warning and an error. The reason we are getting this error is because cc options != gcc options. We have two solutions at hand at this point:

1. Use gcc (we installed it earlier)
2. Change the compiler options to use cc's compiler options instead of gcc.

Using gcc compiler
To use the gcc compiler instead of cc, do the following:

bash-3.00# CC=`which gcc`
bash-3.00# export CC
bash-3.00# make

…