Showing entries 51 to 60 of 372
« 10 Newer Entries | 10 Older Entries »
Displaying posts with tag: Technology (reset)
FUD/not-FUD in NoSQL

When I think of FUD (Fear, Uncertainty, Doubt), I think of the intangible (and irrational) sense that a given technology is inherently bad, will cause your site to go down, and your girlfriend to leave you.  

Over time SQL FUD has cropped up from all the NoSQL evangelists hammering on about how NoSQL solves all the traditional problems RDBMSs have.  Do they have valid points?  In a lot of cases, sure.  But that doesn’t mean that NoSQL is without its own problems.

Part of making peace between the SQL and NoSQL camps should include being honest about the strengths and weaknesses of each technology, so engineering decisions get made, not sales decisions.  Every technology has its strengths and weaknesses, just like physical materials in, say, …

[Read more]
MySQL Connector/Net 6.4.0 Alpha has been released

MySQL Connector/Net 6.4.0, a new version of the all-managed .NET driver for MySQL has been released. This release is of Alpha quality and is intended for testing and exposure to new features. We strongly urge you to not use this release in a production environment.

Version 6.4.0 is intended for use with versions of MySQL from 5.0 – 5.5

It is now available in source and binary form from here 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.)

New features in this release (please see release notes for more information)

Windows Authentication
This release includes our new support for Windows authentication when connecting to MySQL Server …

[Read more]
Setting up replication with XtraBackup

I attended Vadim Tkachenko’s talk on XtraBackup during MySQL conference in Santa Clara last week. Backups are obviously very important, but the use case I had in mind is this:
Replicating a database that has Innodb tables in it, while keeping both master and slave on line if possible.

Tangent: by the way, I love the native backup utility that was once promised in MySQL 6.0, similar to SQL Server’s way of backup. It was like running “BACKUP myDb to DISK = ‘/backupDirectory/myDb.bak'” under mysql client, but I digress…

I have used mysqldump to accomplish this in the past, but I wondered how XtraBackup would fare in this task, especially after hearing Vadim’s talk and reading news on Percona’s development effort. To cut to the chase, this is my conclusion. Reproducing steps are listed immediately afterwards.
1. …

[Read more]
Poor man’s MySQL replication monitoring

Using MySQL replication slave(s) for reporting (with potentially different storage engines) is a very popular way of scaling database read activities. As usual, you want to be on top of things when replication breaks so end users can be notified and issues addressed. When Nagios, Zabbix, or whatever monitoring tools are not available or otherwise not accessible, there got to be another way. I wrote the following Python script for that purpose. The script can then be scheduled via crontab to check replication status in an interval you define. When things break, you get a notification email.

Notes:
1. I toyed with MySQLdb Python module for this task, but I don’t like the fact that I cannot easily retrieve values via column names in a MySQLdb cursor. If there is an easier way that I am not aware of due to my ignorance, I’d appreciate it if you could let me know.

I then tried pyodbc, but got a Python 2.4 compiling issue. I …

[Read more]
Install MySQLdb module for Python

Update:

Commenter MarkR made a great point: if possible, use some packaging tools, to try to maintain proper dependencies, to the extent that is possible. Install from the source should be Plan B. So, try yum install MySQL-python first.

This is mostly for my own future reference. It’ll be icing on the cake if it helps you!

This is geared for CentOS or Red Hat. Use apt-get or other packaging tools for different flavours of Linux.

1. Get Python module setuptools called easy_install. I love easy_install, by the way, sort of like CPAN for Perl modules;
2. To install MySQLdb package, you would think easy_install MySQLdb would do. But that is not the case. I hope the developer would fix that. Instead, you need:

easy_install MySQL-python

3. If you have build errors, you may need:
yum install python-devel or yum …

[Read more]
How to make MySQL cool again

Jonathan Levin has an excellent blog post titled How to make MySQL cool again. It is almost word for word something I've wanted to write for a long time. Now I don't need to, thanks Jonathan.

Once again Blogger failed to post my comments to his site, so I will make some comments as a new post of my own instead. Jonathan actually lists things that exist already but isn't getting used enough. My list contains also a few things that I don't know if they exist or not.

Hi Jonathan

read more

SELinux and “failed to map segment from shared object” error

I am reading and following examples in MySQL 5.1 Plugin Development. After compiling and moving a .so file (think DLL or Assembly file in Windows) into MySQL plugin directory, I got this message when I tried to create a UDF (User Defined Function):

mysql> create function udf_staticexample returns integer soname 'udf_staticexample.so';
ERROR 1126 (HY000): Can't open shared library 'udf_staticexample.so' (errno: 0 /usr/lib/mysql/plugin/udf_staticexample.so: failed to map segment from shared object: Permission denied)

This is caused by the fact that the .so shared object file is not in the right SELinux security context:

[root@asusfedora plugin]# ll -Z
lrwxrwxrwx. root root …
[Read more]
Data generation with TPC-H’s dbgen for load testing

2011-06-26 update:

I am not sure if there are any changes in the latest make and gcc packages. Anyway, I noticed when run make, I encountered the message below:

make: g: Command not found
make: [qgen] Error 127 (ignored)

To fix this, find where gcc is at, then created a symbolic link g that points to gcc. All is well afterwards:
[root@ip-10-245-209-196 dbgen]# which gcc
/usr/bin/gcc
[root@ip-10-245-209-196 dbgen]# cd /usr/bin/
[root@ip-10-245-209-196 bin]# ln -s gcc g

End update
Recently I found myself doing some data loading benchmark testing with table partition. Data loading and storing for BI/DW/DSS stuff almost always involves data partitioning. SQL Server partition has a nice feature called partition switch, where you can swap data in and out of a partitioned table. …

[Read more]
Seeking input on updating sample my.cnf files

The sample my-small.cnf, my-medium.cnf, my-large.cnf, my-huge.cnf, and my-innodb-heavy-4G.cnf files from MariaDB and Percona (I didn’t bother checking Oracle’s distro) were from the dinosaur age, with comment like this for my-huge.cnf:

This is for a large system with memory of 1G-2G where the system runs mainly MySQL.

So I suggested some updating is needed on IRC and mailing lists. After getting a kick in the pants from the always affable Kurt von Finck (I thought “kick in the pants” is a pretty good rendition of “遣将不如激将”, for those who followed our exchanges in mailing lists), I decided to take this upon myself.

It’s actually not hard to update this. I believe just 6 files in total, at most, need to be touched under the support-files directory inside the trunk: my-small.cnf.sh, my-medium.cnf.sh, my-large.cnf.sh, my-huge.cnf.sh, my-innodb-heavy-4G.cnf.sh, and Makefile. Please let me know if my …

[Read more]
Q&A with Stephen Baker of "Final Jeopardy"

IBM's Watson natural language Question & Answer system made headlines recently with its primetime debut on Jeopardy.  Despite a few embarassing answers, Watson trounced top Jeopardy players Brad Rutter and Ken Jennings.  Watson is built from 90 IBM Power 750 IBM Linux servers with 16 terabytes of memory providing 80 Teraflops of processing power.  Watson is perhaps the most famous "Big Data" systems out there.  Watson's knowledge base consists of 200 million pages of text data that is pre-processed using  …

[Read more]
Showing entries 51 to 60 of 372
« 10 Newer Entries | 10 Older Entries »