Sreekar,
Since the file is being written as a single stream, even if you
designate multiple threads, in effect it will take the same
amount of the time since it will wait to synchronize the output
in the order it needs to be written.
Most SBT enabled backup frameworks like OSB, Symantec and TSM
expect there data to be written from a single thread.
-Sanjay
So folks, bit short notice I know, but i’ll be talking at LAMP stack event tomorrow in London. Loads of interesting stuff about MySQL and the other pieces of the LAMP Stack. You can register here:
http://www.oracle.com/us/dm/17128-emeafm13045970mpp005-oem-1989140.html
Agenda is below..
| Agenda | |
| 09:00 | Registration and welcome coffee |
| 09:30 |
Welcome and Introduction Simon Deighton, MySQL Sales Manager, Oracle |
| 09:45 |
Features and news around Oracle Linux and Oracle
VM Wayne Lewis, … |
September 17, 2013 By Severalnines
Galera cluster has known limitations, one of them is that it uses cluster-wide optimistic locking. This may cause some transactions to rollback. With an increasing number of writeable masters, the transaction rollback rate may increase, especially if there is write contention on the same dataset. It is of course possible to retry the transaction and perhaps it will COMMIT in the retries, but this will add to the transaction latency. However, some designs are deadlock prone, e.g sequence tables. In this blog we present how you can minimize the risk for deadlocks due to the design of Galera.
Test Case
Here is a simple test case. We have a table that contains a column and a row that hold a number and is regularly updated to provide …
[Read more]
In my third year of engineering I decided to take coding very
seriously and started solving questions at codechef and my first question I solved
there was titled "Life, the Universe and Everything" ,
the story is somewhat similar with blogging also, I think this is
the time to take it very seriously.
So here I am starting a blog, and to have some motivation I keep
the title of this post as Life, the Universe and everything :D
.
Well little about me, I am a software developer by profession and
currently working in MySQL.
In this blog I will talk about the features I am working on, and
also about the cool stuff happening in this N00B tech
world.
So just to remind you before you start thinking that this is just
another blog in the oceans of tech …
MySQL 5.6 ships with a default config file that sets the SQL mode to NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES . Here is what happens if you try to insert NULL values into a table with NOT NULL columns:
mysql> create table safetyfirst(
-> id int primary key not null auto_increment,
-> country varchar(60) NOT NULL,
-> product varchar(60) NOT NULL );
Query OK, 0 rows affected (0.24 sec)
mysql> insert into safetyfirst(country) values('Sweden');
ERROR 1364 (HY000): Field 'product' doesn't have a default value
If someone tells you that MySQL 5.6 by default allows you to do this, ask them to prove it using the default settings we use for new installations and check their claim by asking them for the output of SHOW VARIABLES LIKE 'sql%'; .
We would like to use NO_ZERO_DATE, NO_ZERO_IN_DATE, …
[Read more]And that's a wrap! Check out the recording:
Hello!
Coming up this Wednesday, September 18th, 2013 at 12:00pm pacific (19:00 GMT) come and join #DBHangOps to discuss:
- Data warehousing in MySQL
- Shipping large tables from production to your Data warehouse
- Do you use Federated engine?
- What other solutions do you use?
- Answer some questions about MySQL-isms (requested by Tim
Callaghan)
- Why does MySQL have FRM files instead of storing them in a data dictionary table?
- Why doesn't InnoDB support other page sizes?
- Why do we store data in a master.info file?
- What are you excited to see at MySQLConnect?
As always, take a look at …
[Read more]The plug-able storage engine architecture is a design feature that is really separates MySQL/MariaDB from the pack. This feature allows for running the storage engine, or engines that best meet your table's needs. Choosing the right storage engine for your needs can make a huge impact on the performance of your database, but like many things in MySQL there can sometimes be too many options available to make the right choice clear.
The MySQL Reference Manual advises:
Use a CREATE TABLE statement to specify the layout of your
table:
mysql> CREATE TABLE pet (name VARCHAR(20), owner
VARCHAR(20),
-> species VARCHAR(20), sex CHAR(1), birth DATE, death
DATE);
...
Several types of values can be chosen to represent sex in animal
records, such as 'm' and 'f', or perhaps 'male' and 'female'. It
is simplest to use the single characters 'm' and 'f'.
I will supplement that with this post about representing sex (gender) in people records. I have to consider the name, the possible values, the data type, and the constraints. It won't be simplest.
Should the column name be 'sex'?
First consider …
[Read more]
Crap… ok. Looking at the notes – it’s fixed in mysql 5.6.13, but
cluster 7.3.2 comes with 5.6.11.
I’m not knowledgable about compiling… so I’m only going to take 1
stab at extracting 5.6.13 source into the mysql-cluster-gpl-7.3.2
directory – then try to compile it.
Otherwise I’ll be doing 7.3.0! 🙂
aha you beat me to it.. i tried 7.3.2 and it wouldn’t compile.. so am assuming it would need a similar patch applied..