Back-story: A developer came to me and wanted explanation for a weird behavior in MySQL. They inserted a record (to InnoDB table), committed, and after receiving a message (on another application) tried to read that inserted record immediately, but the newly inserted record was not found. Problem only happened in production, but not always (quite frequently).
After comparing the MySQL parameter files between production and development environments I discovered that in production autocommit was disabled to make MySQL behave more like Oracle. This setting was removed from development after we rebuilt the environment (to use multiple MySQL instances with Oracle (more...)
As every year the DOAG (German Oracle User Group) Conference will take place Nürnberg/Germany from the 20th November until 22nd November 2012.
The Call for Papers is already open and ends on 30th June 2012:
German Link: http://www.doag.org/de/events/konferenzen/doag-2012/fuer-referenten.html
English Link: http://www.doag.org/en/events/konferenzen/doag-2012/fuer-referenten.html
Once again, I (more...)
This is THE
MySQL performance book. Period!
Every chapter is very well crafted, with a precise balance between theory and practice, and full of invaluable nuggets, sometimes transcending the MySQL arena and applicable to any database!
Such cases are Chapter 2-Benchmarking MySQL and Chapter 3-Profiling Server Performance, very solid foundations for the reading ahead.
All over the text, authors propose tools, examples of use and proven diagnostic techniques, that will greatly improve your performance firefighter skills and enhance your knowledge of MySQL internals. Nevertheless, what I liked the most from this book is taking into (more...)
Interesting take on what managers are thinking: http://quickbase.intuit.com/blog/2012/01/09/10-things-your-boss-isnt-telling-you/
I've been doing lately quite many database clustering implementations; Oracle RAC and since we have many MySQL instances in production, had to find a good way to make MySQL instances highly available also.
One good solution for this is managing MySQL instances with clusterware and since we are planning to use Oracle RAC on Oracle Enterprise Linux anyway, then Oracle Clusterware is an excellent candidate for this task. Also... Oracle Clusterware is included with Oracle Enterprise Linux at no additional charge.
Requirements I had:
- Multiple MySQL instances running in the same cluster, in case of node failure affected MySQL instances (more...)
After 30 years of Oracle, I've found myself using MySQL recently. I came across a little thing that surprised me. I'm by no means the first to trip over this - I found this 2006 post from Peter Zaitsey
on the same topic.
MySQL lets you write a group by statement that references columns that aren't in the group by, and aren't aggregates. For example:
mysql> select table_name, column_name, count(*)
-> from information_schema.columns
-> where table_schema = 'information_schema'
-> group by table_name
-> limit 5;
| table_name | column_name | count(*) |
| CHARACTER_SETS | CHARACTER_SET_NAME | (more...)
There was an interesting index related performance problem on Stack Overflow recently. The problem was to check an input string against a table that holds about 2000 prefix patterns (e.g.,
LIKE 'xyz%'). A fast select is needed that returns one row if any pattern matches the input string, or no row otherwise.
I believe my solution is worth a few extra words to explain it in more detail. Even though it’s a perfect fit for Use The Index, Luke it’s a little early to put it as an exercise there. It is, however, a very good complement (more...)
The InnoDB Plugin manual is now available on the MySQL web site.
I've been pretty quiet lately, because I'm in a transitional period. After 10 years on documentation for Oracle Database and other enterprise server products, I'm switching to the InnoDB group that already works with MySQL. New development environments, new customers, it's an exciting time!A decade seems to be the right timeframe for me. It was 10 years at IBM before that. Check back in 2019, I'm
In Europe, many people love Open Source with its connotations of sharing and village co-operatives. On the other hand, many Europeans don’t like the big, successful American companies (witness the ritual McDonalds-bashing).
This emotional preference for Open Source to big American companies is why the EU competition authorities have decided (more...)
Here I'm following up my previous post Using linguistic indexes for sorting in Oracle
. I don't much like the Oracle solution, that requires creating a special index to speed up sorting, but... at the same time its very powerful, allows to index in many languages and no database changes are needed.
In this post I’ll take a look at the two popular open source databases MySQL and PostgreSQL. I'll take a look only at features, that the database has included and that can be used without any special application changes.
Starting from 8.4, collation (sorting) rules (more...)