Sun is shining and the warm wind is blowing and bringing in new and novel ideas for the technology  blogs and database are no exception. From the SQL Server to MySQL and up to Oracle, blogs are bubbling with warm and cool blog posts and we present you the pick of the week in this Log Buffer #228 edition of Log Buffer.

Oracle:

There is an Exadata Virtual Conference, which has been organized by Tanel Poder on August 3rd and 4th. Kerry Osborne has more details.

The new release of  DB Optimizer , version 3.o, from Embarcadero has awesome new feature : explain plan overlay onto VST diagrams! …

Alright, like i said we will discuss a different scenario in this tutorial to further clarify the concept of association classes so here is the scenario.

We recently deployed a new NFS filer running on top of Nexenta using ZFS and noticed that some of our systems were having performance issues. Writes to the NFS system on most hosts were snappy, but reads from NFS were capping out at around 3M per second on a Gig-E network interface on a handful of hosts.

Systems that were identically configured in every way - kernel version, nfs package version, hardware, mount options, etc. were behaving differently. One would read and write at around 100M yet another would cap out at 3M.

Our systems guys did some troubleshooting and diagnosis on the network and could not find any issue there. So we went ahead and tested an scp from the NFS server to a problematic host.

The scp would run closer to 80M per second, so it seems that the problem was NFS itself.

We checked and double checked our configs, settings, sysctl.conf, versions and could not find …

There are several parameters to set a timeout on MySQL :

But I would like to focus on wait_timeout (or interactive_timeout depending on how you connect)

This timeout allows MySQL to automatically close a connection in case of non-activity during the time defined by this parameter (default value is 28000 seconds).

The problem I wish to explain here may happen when this timeout is set to a low value (about 10 to 30 seconds).

Indeed, in this case, this timeout may have serious consequences, look at that :
[The wait_timeout parameter is set to 10 seconds in this case]

You are connected through the standard MySQL client and you need to run a delete query (bypass autocommit) :

• mysql> start transaction; …

Unified Modeling Language (UML) is a standardized general-purpose modeling language in the field of object-oriented software engineering. The standard is managed, and was created by, the Object Management Group.

Last week I gave a talk entitled “Don’t Thrash: How to Cache your Hash.” The talk took place at the Workshop on Algorithms and Data Structures (ADS) in a medieval castle turned conference center in Bertinoro, Italy. An earlier version of this work (with the same title) appeared at the HotStorage conference in Portland, OR. Tokutek co-founders Bradley, Martin, and I are coauthors on the work, along with students and other faculty at Stony Brook University.

The talk title is colorful and doggerel-y. Here’s what the title means. “Cache your hash”—the so-called Bloom Filter type data structure. A Bloom filter acts like a negative cache, …

MySQL Connector/Net 6.4.3, a new version of the all-managed .NET driver for MySQL has been released.  This is a GA release and is intended for full production deployment.

Version 6.4.3 is intended for use with versions of MySQL from 5.0 – 5.5

It is now available in source and binary form from [http://dev.mysql.com/downloads/connector/net/6.4.html] and mirror
sites (note that not all mirror sites may be up to date at this point of time
- if you can’t find this version on some mirror, please try again later or choose another download site.)
The release is also available for download on the My Oracle Support (MOS) and will be available from Oracle eDelivery.

** New features found in 6.4 include (please see release notes for more information) **

* Windows Authentication*
This release includes our …

MySQL Connector/Net 6.2.5, a update to our all-managed .NET driver for MySQL has been released.  This is an update to our legacy 6.2 version line. All new development should be using a more recent product such as 6.4.3.

Version 6.2.5 is intended for use with versions of MySQL from 4.1 – 5.1.  It is not suitable for use with MySQL 5.5 or later.

It is now available in source and binary form from [http://dev.mysql.com/downloads/connector/net/] and mirror
sites (note that not all mirror sites may be up to date at this point of time
- if you can’t find this version on some mirror, please try again later or choose another download site.)

This update includes more than 45 fixes from 6.2.4.  Please review the change log that is included with the product to determine the exact nature of the changes.

Enjoy and …

Last week I gave a talk entitled “Don’t Thrash: How to Cache your Hash.” The talk took place at the Workshop on Algorithms and Data Structures (ADS) in a medieval castle turned conference center in Bertinoro, Italy. An earlier version of this work (with the same title) appeared at the HotStorage conference in Portland, OR. Tokutek co-founders Bradley, Martin, and I are coauthors on the work, along with students and other faculty at Stony Brook University.

The talk title is colorful and doggerel-y. Here’s what the title means. “Cache your hash”—the so-called Bloom Filter type data structure. A Bloom filter acts like a negative cache, …

I’ve just sent an email to the Maatkit discussion list to announce a planned change to how Maatkit (and Aspersa) are developed. In short, Percona plans to create a Percona Toolkit of MySQL-related utilities, as a fork of Maatkit and Aspersa. I’m very happy about this change, and I welcome your responses to that thread on the discussion list.

Related posts:

1. Aspersa, a new opensource toolkit
2. Four companies to sponsor Maatkit development
3. How …