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Showing entries 1 to 6

Displaying posts with tag: fractal tree (reset)

Disabling Transparent Hugepages for TokuDB
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If you want to use TokuDB with MariaDB, MySQL, or Percona Server, you will need to disable support for transparent hugepages in Linux.

Fortunately, this is very easy to check, and to change.

An easy way to check is with:

cat /sys/kernel/mm/transparent_hugepage/enabled

This will return something like:

[always] madvise never

Note the word surrounded by “[]” is what this option is set to. So the above is set to “always”. To disable it, we want it set to “never”.

I’ve found the easiest way to change/set this is to add the below to your /etc/rc.local file (and then reboot your system):

if test -f /sys/kernel/mm/transparent_hugepage/enabled; then
   echo never >
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Enabling TokuDB in MariaDB is a Breeze
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TokuDB is gaining more and more popularity and many people are finding it very helpful for certain cases.

Using/enabling it in some distributions can be quite a pain, but enabling it in MariaDB is easy as 1-2-…, well, only 1-2, since that’s all there is to it!

1. Ensure you have the correct MariaDB version:

  • MariaDB 5.5.36+
  • MariaDB 10.0.9+
  • Note: Linux 64-bit systems only – specific packages include: Ubuntu, Debian, Fedora, CentOS, Red Hat
  • Note: If using the Linux tarball – it must be the version built with glibc 2.14+

2. Run this command:

INSTALL SONAME 'ha_tokudb';

or update my.cnf file with:

[mysqld]
plugin-load=ha_tokudb

There is one requirement from

  [Read more...]
Put your MySQL Knowledge to Good Use with Tim Callaghan at Percona Live-London, November 12
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Attending Percona Live in London next week?

Don’t miss the chance to hear Tokutek’s Vice President of Engineering, Tim Callaghan, discuss how to use your MySQL knowledge to become an instant MongoDB Guru and the advantages of using Fractal Tree&#174 indexes in MySQL and MongoDB. Tim will be speaking about these topics in two separate sessions at 12:00pm and 5:00pm on November 12.

For more information on these sessions and Percona Live-London, visit https://www.percona.com/live/london-2013/users/tim-callaghan.

A TokuDB Stall Caused by Conflicting Transactions When Opening a Table
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One of our customers reported that ‘create table select from’ statements stall for a period of time equal to the TokuDB lock timeout.  This indicated a lock conflict between multiple transactions.  In addition, other MySQL clients that were opening unrelated tables were also stalled.  This indicated that some shared mutex is held too long.  We discuss details about this bug and how it was fixed.  The bug fix will be distributed in TokuDB 7.1.0.

Example
Suppose that we set the tokudb lock timeout to 60 seconds just to exaggerate the stall.

mysql> set global tokudb_lock_timeout=60000;
Query OK, 0 rows affected (0.00 sec)

We then create a simple table.

mysql> create table s (id int primary key);
Query OK, 0 rows affected (0.02







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Loading Air Traffic Control Data with TokuDB 4.1.1
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TokuDB has a big advantage over B-trees when trickle loading data into existing tables. However, it is possible to preprocess the data when bulk loading into empty tables or when new indexes are created. TokuDB release 4 now uses a parallel algorithm to speed up these types of bulk insertions. How does the parallel loader performance compare with the serial loader? We use the Air Traffic Control (ATC) data and queries described in a Percona blog and also used in an experiment with TokuDB 2.1.0 to gain some insight.

Our ATC data is about 122M rows in size, is stored in a 40GiB CSV file, and can be found in our Amazon S3 public

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TokuDB speeds up “replace” and “insert ignore” operations by relaxing the affected rows constraint
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In posts on June 30 and July 6, we explained how implementing the commands “replace into” and “insert ignore” with TokuDB’s fractal trees data structures can be two orders of magnitude faster than implementing them with B-trees. Towards the end of each post, we hinted at that there are some caveats that complicate the story a little. In this post, we explain one of the complications: the calculation of affected rows.

MySQL returns the number of rows affected by a “replace” or “insert” statement to the client. For the “replace” statement, the number of affected rows is defined to be

  [Read more...]
Showing entries 1 to 6

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