Calpont is pleased to announce high performance sub-query support with the latest alpha version (1.1.2) of InfiniDB.  We’re especially happy about this release because polls done by MySQL have consistently shown – year after year – that slow subquery performance is one of the top items the MySQL community wants fixed in the server. It’s been complex work for sure, but the Calpont engineering team has come through again and delivered high...

Users of HeidiSQL 3.x may have missed this feature since grid and BLOB editing was rewritten for v4: A preview area for images. Now it's even more powerful than before: it detects and loads various kinds of images (JPG, PNG, GIF, BMP, PSD, TIF and more). Also, the new preview area does not take valuable space when you're in some grid, as it's placed below the database tree:

I know it has been a long time between drinks/posts, but I've been busy -- I promise! :)

Today I spent a considerable amount of time trying to figure out why an INSERT SELECT ON DUPLICATE KEY UPDATE was not behaving as I would expect.

Here is an example to illustrate:

CREATE TABLE t1 (
  id INT AUTO_INCREMENT,
  num INT NOT NULL DEFAULT 0,
  PRIMARY KEY (id)
);

CREATE TABLE t2 (
  id INT NOT NULL,
  num INT
);

INSERT INTO t1 VALUES (1, 10);
INSERT INTO t2 VALUES (1, NULL);


INSERT INTO t1
  SELECT id, num
  FROM t2
ON DUPLICATE KEY UPDATE
  num=IFNULL(VALUES(num), t1.num);

To convert the above query into plain English -- I'm saying, INSERT into table t1 the id and num …

We have all been caught out with using SET and not realizing that the default GLOBAL Scope (since 5.0.2) does not change the current SESSION scope.

I was not aware until today that changing GLOBAL scope has some exceptions that also automatically affect SESSION scope.

What I expected with a change in the GLOBAL scope is no affect SESSION scope. For example.

mysql> SHOW GLOBAL VARIABLES LIKE 'read_buffer_size';
+------------------+--------+
| Variable_name    | Value  |
+------------------+--------+
| read_buffer_size | 131072 |
+------------------+--------+
1 row in set (0.00 sec)

mysql> SHOW SESSION VARIABLES LIKE 'read_buffer_size';
+------------------+--------+
| Variable_name    | Value  |
+------------------+--------+
| read_buffer_size | 131072 |
+------------------+--------+
1 row in set (0.00 sec)

mysql> SET GLOBAL read_buffer_size=1024*256;
Query OK, 0 rows affected (0.00 sec)

mysql> SHOW GLOBAL VARIABLES LIKE …

By default MySQL allows you to create user accounts and privileges with no password. In my earlier MySQL Best Practices: User Security I describe how to address the default installation empty passwords.

For new user accounts, you can improve this default behavior using the SQL_MODE variable, with a value of NO_AUTO_CREATE_USER. As detailed via the 5.1 Reference Manual

NO_AUTO_CREATE_USER

Prevent the GRANT statement from automatically creating new users if it would otherwise do so, unless a nonempty password also is specified.

Having set this variable I attempted to show the error of operation to demonstrate in my upcoming “MySQL Idiosyncrasies that bite” presentation. …

Everybody working on Unix or in the database world stumbles over Oracle Berkeley DB every now and then. DB is an Open Source embedded database used by applications like OpenLDAP or Postfix. Traditionally it followed mostly a key-value access pattern. Now what caught my attention was the fact that the recently released DB 5.0 provides an SQLite-like C API with the promise of providing better concurrency and performance than regular SQLite. Time to give it a shot.

So I grabbed the source distribution, checked the documentation and saw that I shall use the …

Henrik Ingo from the Open Database Alliance (ODBA) did an interview with Oli Sennhauser of FromDual about the European MySQL database landscape and its future. If you want to know more about our opinion in this matter please read here: http://opendba.wordpress.com/2010/05/31/interview-oli-sennhauser-of-fromdual-about-european-database-landscape/.

For more technical insight see also our former presentation: MySQL, where are you going?.

If you’re near South Carolina next weekend, consider attending Southeast Linux Fest! There’s a list of illustrious speakers including several well-known in the database world: Joshua Drake and Andrew Dunstan (PostgreSQL), D. Richard Hipp (SQLite), and yes, yours truly (MySQL), plus a MySQL name that’s new to me: Brandon Checketts. There are a ton of non-database sessions too! Check out the full speaker & session list. This was a great show last year; I highly encourage everyone to attend.

Related posts:

1. Recap of Southeast Linux Fest 2009
2. How Linux iostat …

4 min 20 sec

So next time somebody complains about NDB taking a long time in CREATE TABLE, you’re welcome to point them to this :)

• A single CREATE TABLE statement
• It had ONE column
• It was an ENUM column.
• With 70,000 possible values.
• It was 605kb of SQL.
• It ran on Drizzle

This was to test if you could create an ENUM column with greater than 216 possible values (you’re not supposed to be able to) – bug 589031 has been filed.

How does it compare to MySQL? Well… there are other problems (Bug 54194 – ENUM limit of 65535 elements isn’t true filed). Since we don’t have any limitations in Drizzle due to the FRM file …

This run is very similar what I had on Intel SSD X25-M card, but now I use FusionIO 80GB SLC card. I chose this card as smallest available card (and therefore cheapest. On Dell.com you can see it for about $3K). There is also FusionIO IO-Xtreme 80GB card, which is however MLC based and it could be not best choice for FlashCache usage ( as there high write rate on FlashCache for both reading and writing to/from disks, so lifetime could be short).

Also Facebook team released WriteThrough module for FlashCache, which could be good trade-off if you want extra warranty for data consistency and your load is mostly read-bound, so I tested this mode also.

All …