It has been just over 4 months since I started working on libAttachSQL for HP's Advanced Technology Group. Today marks the first (and hopefully only) RC release of the library.

Connection Groups

The only real new feature that has been added to 0.9.0 is the concept of connection groups which is something I'm pretty excited about. Internally libAttachSQL uses event loops to supply the non-blocking API. Connection Groups join a bunch of connections together into a group that uses a single event loop. This makes things much more efficient internally and makes applications easier to code too.

Here is a simplified example of how to use it (for a more detailed example see our example in the documentation).

First we need to create the group and add connections to …

A few months back, Michael wrote about reconnecting orphaned *.ibd files using MySQL 5.6. I will show you the same procedure, this time for partitioned tables. An InnoDB partition is also a self-contained tablespace in itself so you can use the same method described in the previous post.

To begin with, I have an example table with a few orphaned partitions and we will reconnect each partition one by one to the original table.

mysql [localhost] {msandbox} (recovery) > SHOW CREATE TABLE t1 G
*************************** 1. row ***************************
Table: t1
Create Table: CREATE TABLE `t1` (
[...]
KEY `h_date` (`h_date`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
/*!50100 PARTITION BY RANGE (year(h_date))
(PARTITION p0 VALUES LESS THAN (2006) ENGINE = InnoDB,
PARTITION p1 VALUES LESS THAN (2010) ENGINE = InnoDB,
PARTITION …

The new InnoDB Labs release contains the ability to create and use independent multi-table general tablespaces.

This feature will provide a way to group tables together into tablespaces at a location and filename of your choosing.  Tables using row formats of Redundant, Compact, and Dynamic can be combined together into the same general tablespace. Compressed tables with the same key_block_size can also be combined together.

The SQL syntax for creating an empty general tablespaces is:

CREATE TABLESPACE `tblspace_name` ADD DATAFILE 'tablespace.ibd' [FILE_BLOCK_SIZE=n];

The filename can contain an absolute path or a path relative to the data …

I had a few more suggestions thrown out at me before I could wrap this one up.

• Try disabling the RAID controller read-ahead
• Try a few custom options to XFS
• Try RAID-10

First, my final “best” state benchmarks for comparison:

Percona Toolkit’s  pt-table-checksum performs an online replication consistency check by executing checksum queries on the master, which produces different results on replicas that are inconsistent with the master – and the tool pt-table-sync synchronizes data efficiently between MySQL tables.

The tools by default use the CRC32. Other good choices include MD5 and SHA1. If you have installed the FNV_64 user-defined function, pt-table-sync will detect it and prefer to use it, because it is much faster than the built-ins. You can also use …

I was talking with Todd Hoff recently over at High Scalability about a trend I’ve seen of late. ME: I really liked this post by Zoli Kahan from Clay.io.  AWS, cloudflare, docker, haproxy, mysql, mongo, memcache, ansible.  They use just about every technology being talked about these days.   Todd: Yah, that’s why I asked […]

#DBHangOps 10/16/14 -- MySQL SYS, Graphs, and more!

Hello everybody!

Join in #DBHangOps this Thursday, October, 16, 2014 at 11:00am pacific (18:00 GMT), to participate in the discussion about:

• New in TokuDB 7.5 (rescheduled for next time!)
• MySQL SYS features and discussion -- what do you want to see in MySQL SYS?
• What graphs make a good dashboard?

You can check out the event page at https://plus.google.com/events/cml4a2uo9q77jr1pejste9pua1c on Thursday to participate.

As always, you can still watch the #DBHangOps twitter search, the @DBHangOps twitter feed, or this blog post to get a link for the google hangout on …

Following Article Describes How To Perform Most Basic MYSQL / MariaDB Queries on Fedora 20? or How to Run MySQL on Fedora 20 ? Which is Latest Version of Linux Based Operating System Project. Last Operation of This Assignment also describes How to change MySQL 'Root' User password on Linux.
It is also a part of 3rd Year, 5th sem Computer Engineering Academic Curriculum of Pune University. As PL 1 Subject. Group A, Assignment 1. It's Problem Statement And Solution is Given Below. You may also Checkout Database Management System complete syllabus & Tutorial of 5th sem subject called Database Management systems application.

It is possible to disallow users from using old_passwords=1. This can be done by adding 'maximum-old_passwords=0' to your my.cnf

This prevents users from generating passwords hashes in pre-4.1 format. In MySQL 5.7 old_passwords=1 is already disabled, so this is only useful on 5.6 and earlier.

Be aware that this also restricts old_passwords=2 which is needed for sha256 hashes.

mysql> select @@old_passwords;
+-----------------+
| @@old_passwords |
+-----------------+
|               0 |
+-----------------+
1 row in set (0.00 sec)

mysql> set old_passwords=1;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> show warnings;
+---------+------+----------------------------------------------+
| Level   | Code | Message                                      |
+---------+------+----------------------------------------------+
| …

This year’s MySQL Central at Oracle Open World was an exhilarating experience. In contrast to the previous year’s MySQL Connect events, MySQL have now got their own Central at the main Oracle Open World. In the previous years, we were always short on time and trying to get a lot of sessions into just two days was just to much. This time I could both present sessions, attend sessions by other users, and also to talk to people in the MySQL community: something that I really enjoy and also find very valuable to see where we should be heading.

This year, the “MySQL Fabric Team” representation on MySQL Central was me and Narayanan Venkateswaran, which is heading the sharding solution in MySQL Fabric. Together with the conference, we also released MySQL Fabric 1.5.2 as the GA release of MySQL Fabric 1.5 containing a few new features:

• Server …