Mark Callaghan at facebook tested the test release of MySQL 5.6.3 and he has found some performance improvement with InoDB feature. Read below...
Mark tried two of the previews for MySQL 5.6.3 at http://labs.mysql.com/. His first attempt with the multi-threaded slave preview was not successful. Parallel apply on the slave is serial when the master does not also run 5.6.3. He said (I hope this changes as a typical upgrade is first done on the slave.)
He was more successful with the InnoDB...
Wednesday, July 27, 2011
Reduced contention during datafile extension
Another performance problem found by PoorMansProfiler
Innam rana said in his blog post on innodb blog:
InnoDB has an internal file system management module that primarily manages the space in the data files. One of the pain points was the coarse level of locking used when a data file has to be extended. More about this issue can be found here. In the latest labs release we have fixed this problem.
When we need to extend a data file inside InnoDB we write zero filled pages synchronously to the file. The user thread...
Friday, July 22, 2011
When does InnoDB compress and decompress pages?
There are two sections for rows in the page format for InnoDB compressed tables. The compressed section has one or more rows and must be decompressed to access individual rows. The modification log has uncompressed rows and rows can be accessed without decompressing. The modification log is used to avoid decompressing and then possibly recompressing the compressed section on every row change. The buffer pool also has separate uncompressed copies of some pages so that every row read does not require a page decompression.
I...
Tuesday, July 19, 2011
MySQL Cluster Architecture
Introduction:
MySQL Cluster is a write-scalable, real-time, ACID-compliant transactional database, combining 99.999% availability with the low TCO of open source. Designed around a distributed, multi-master architecture with no single point of failure, MySQL Cluster scales horizontally on commodity hardware to serve read and write intensive workloads, accessed via SQL and NoSQL interfaces.
MySQL Cluster's real-time design delivers...
Thursday, July 14, 2011
getopts in shell script
getopts
The getopts command simplifies the task of validating and parsing command line options and arguments for your shell scripts.
Syntax:
getopts <optstring name> [arg...]
Example:
Step1: First I define all my option holding variables.
ListFiles=0
MoveFiles=0
email=""
Step2: While loop.
The following while statement loops through all the options and sets them to the corresponding variable. getopts returns true while there are options to be processed. The argument string, here "lme:h", specifies which...
Friday, July 1, 2011
GET SIZE OF DIRECTORY (EXCLUDE SUBDIRECTORY) IN UNIX
We all know du command to get the size of a directory. But the problem is when you use "du <directory name>" it will give you the list of all subdirectory including the directory you want with size.
Bt what if i only want the size of directory which i have passed as an argument and not all the subdirectory?
In that senario we can use:
du -sh <directory name> ...
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