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Displaying posts with tag: 5.1 (reset)
Using the event scheduler to purge the process list



Two of the most common tasks for database administrators are cleaning the process list from unresponsive queries and remove idle connections that are filling the connection pool.
Both tasks are related to poor usage of the database. In a perfect world, users would only run queries designed, tested, and benchmarked by the DBA or the project manager, and the application servers would never allocate more connections than planned.

But users are human, and an unpredictable amount of unplanned events can happen everywhere. When I was consulting, the above cases were quite common.
Before MySQL 5.1, the only method to clean up the process list was by hand, or using a cron job to do it from time to time.
MySQL 5.1 …

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Is the Federated engine useful to you?




Followers of my blogs and talks know that I am partial to the Federated engine. Not much as a normal way of storing data, but more as an auxiliary device to create innovative schemes.
A few years ago I wrote an article, Federated: the missing manual where I listed most of the gotchas that you can meet when using the Federated engine. This article alone would be enough to discourage you from using Federated in production. If you attempt to use a Federated table like a normal one, your server will suffer, and possibly crash.


Add the sad fact that …

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MySQL Use case Competition - When theory meets practice

MySQL 5.1 is almost ready for prime time, but in the meantime some brave users have already started putting it to work in production environment.

MySQL wants to hear from these intrepid souls. The MySQL 5.1 use Case competition is under way. We want feedback from users who have found a practical usage for 5.1 features, and also from the ones who have met usability challenges.

Two articles have already been published from the competition submissions. One …

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A 5.1 QEP nicety - Using join buffer

I was surprised to find yesterday when using MySQL 5.1.26-rc with a client I’m recommending 5.1 to, some information not seen in the EXPLAIN plan before while reviewing SQL Statements.

Using join buffer

+----+-------------+-------+--------+---------------+--------------+---------+------------------------+-------+----------------------------------------------+
| id | select_type | table | type   | possible_keys | key          | key_len | ref                    | rows  | Extra                                        |
+----+-------------+-------+--------+---------------+--------------+---------+------------------------+-------+----------------------------------------------+
|  1 | SIMPLE      | lr    | ALL    | NULL          | NULL         | NULL    | NULL                   |  1084 | Using where; Using temporary; Using filesort |
|  1 | SIMPLE      | ca    | ref    | update_check  | update_check | 4       | XXXXXXXXXXXXXXXXX      |     4 | Using …
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Discover MySQL 5.1, Italian Webinar

On Wednesday, September 17 there will be a web based seminar on MySQL 5.1. 

Seminar will be in Italian and anyone who is interested is invited to join us!

You can find details here.

If you are a database administrator or a developer and you are courious about new features coming with MySQL 5.1 then this is the right webinar to attend. In the meantime, to better understand MySQL 5.1, take have a look at "Inside MySQL 5.1" white paper.

See you soon! 

 

Discover MySQL 5.1, Italian Webinar

On Wednesday, September 17 there will be a web based seminar on MySQL 5.1. 

Seminar will be in Italian and anyone who is interested is invited to join us!

You can find details here.

If you are a database administrator or a developer and you are courious about new features coming with MySQL 5.1 then this is the right webinar to attend. In the meantime, to better understand MySQL 5.1, take have a look at "Inside MySQL 5.1" white paper.

See you soon! 

 

Discover MySQL 5.1, Italian Webinar

On Wednesday, September 17 there will be a web based seminar on MySQL 5.1. 

Seminar will be in Italian and anyone who is interested is invited to join us!

You can find details here.

If you are a database administrator or a developer and you are courious about new features coming with MySQL 5.1 then this is the right webinar to attend. In the meantime, to better understand MySQL 5.1, take have a look at "Inside MySQL 5.1" white paper.

See you soon! 

 

Some quirks of circular and row-based replication

One of the new features introduced by MySQL 5.1 is row-based replication.

Unlike the classic statement-based replication, used in MySQL up to version 5.0, row-based replication transfers the data instead of the statement used to create it.

If you want to have a taste of row-based replication, you can do some experiments with MySQL Sandbox.

First, we create a sandbox of circular replication with MySQL 5.0

./make_replication_sandbox --topology=circular --how_many_nodes=3 \
/path/to/mysql-5.0.51a-YOUR_OS.tar.gz

cd $HOME/sandboxes/rcsandbox_5.0.51
./n1 -e "create table test.t1(i int)"
./n3 -e "insert into test.t1 values (@@server_id)"
./use_all "select * from test.t1"
# server: 1:
i
101
# server: 2:
i
102
# server: 3:
i
103


This is statement-based replication at its best.

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