Disk space issues are common, and they’re often difficult to solve quickly. One way to recover some space is by enabling InnoDB compression.

First, of course, you want to make sure you’ve covered alternative solutions. Can you archive data? Do partitioning/sharding? These generally involve application changes and can take longer.

You may need to first do conversion to InnoDB.

While compression is available for MyISAM via myisampack, and this can be useful for some use cases (for example, if you are rotating out tables on a monthly basis), it makes the tables read-only, so generally you will want to first convert MyISAM tables to InnoDB.

Things to watch for in the schema: After working on functional and performance issues with full-text indexes after conversion to InnoDB, I wouldn’t recommend it. Application changes are also required to rewrite queries. You can consider outsourcing these to a tool …

The LZMA algorithm implemented by the xz compression software package is one of the compression algorithms used by TokuDB for MySQL and TokuMX for MongoDB.  Unfortunately, valgrind's memcheck reports an uninitialized variable problem in the …

Astute readers will note that InnoDB already had compression since the MySQL 5.1 plugin. We are using the terminology of ‘Page Compression’ to describe the new offering that will ship with MySQL 5.7, and ‘InnoDB Compression’ for the earlier offering.…

Being schemaless is one of the key features of MongoDB. On the bright side this allows developers to easily modify the schema of their collections without waiting for the database to be ready to accept a new schema. However schemaless is not free and one of the drawbacks is write amplification. Let’s focus on that topic.

Write amplification?

The link between schema and write amplification is not obvious at first sight. So let’s first look at a table in the relational world:

mysql> SELECT * FROM user LIMIT 2;
+----+-------+------------+-----------+-----------+----------------------------------+---------+-----------------------------------+------------+------------+
| id | login | first_name | last_name | city      | country                          | zipcode | address                           | password   | birth_year | …

On my post last week, I analysed some of the most common compression tools and formats, and its compression speed and ratio. While that could give us a good idea of the performance of those tools, the analysis would be incomplete without researching the decompression. This is particularly true for database backups as, for those cases where the compression process is performed outside of the production boxes, you may not care too much about compression times. In that case, even if it is relatively slow, it will not affect the performance of your MySQL server (or whatever you are using). The decompression time, however, can be critical, as it may influence in many cases the MTTR of your whole system.

Testing …

This week we are talking about size, which is a subject that should matter to any system administrator in charge of the backup system of any project, and in particular database backups.

I sometimes get questions about what should be the best compression tool to apply during a particular backup system: gzip? bzip2? any other?

The testing environment

In order to test several formats and tools, I created a .csv file (comma-separated values) that was 3,700,635,579 bytes in size by transforming a recent dump of all the OpenStreetMap nodes of the European portion of Spain. It had a total of 46,741,126 rows and looked like this:

171773  38.6048402      -0.0489871      4       2012-08-25 00:37:46     12850816        472193  rubensd
171774  38.6061981      -0.0496867      2       2008-01-19 10:23:21     666916  9250 …

Ok, so I wanted to look into the new compression options of MEB 3.10.

And I would like to share my tests with you. Remember, they’re just this, tests, so please feel free to copy n paste and obtain your own results and conclusions, and should I say it, baselines, in order to compare future behaviour, on your own system.

An Oracle Linux 6.3 virtual machine with 3Gb RAM, 2 virtual threads, on a 1x quad core, windows laptop. Not pretty, but hey.

So, these tests are solely about backup. I’ll do restore when I get some *more* time.

First up, lets compare like with like, i.e. MEB version 3.9 & 3.10:

Let’s make this interesting, hence, want to use as much resources available as possible, read, write, process threads and number of buffers.

mysqlbackup --user=root --password=oracle --socket=/tmp/mysql5614.sock \
--backup-dir=/home/mysql/MEB/test --with-timestamp …

Ok, so I wanted to look into the new compression options of MEB 3.10.

And I would like to share my tests with you. Remember, they’re just this, tests, so please feel free to copy n paste and obtain your own results and conclusions, and should I say it, baselines, in order to compare future behaviour, on your own system.

An Oracle Linux 6.3 virtual machine with 3Gb RAM, 2 virtual threads, on a 1x quad core, windows laptop. Not pretty, but hey.

So, these tests are solely about backup. I’ll do restore when I get some *more* time.

First up, lets compare like with like, i.e. MEB version 3.9 & 3.10:

Let’s make this interesting, hence, want to use as much resources available as possible, read, write, process threads and number of buffers.

mysqlbackup --user=root --password=oracle --socket=/tmp/mysql5614.sock \
--backup-dir=/home/mysql/MEB/test --with-timestamp …

We have released some code in a labs release that does compression at the InnoDB IO layer. Let me answer the most frequently asked question. It will work on any OS/File system that supports sparse files and has “punch hole” support. It is not specific to FusionIO. However, I’ve been told by the FusionIO developers that you will get two benefits from FusionIO + NVMFS, no fragmenation issues and more space savings because of a smaller file system block size. Why the block size matters I will attempt to explain next.

The high level idea is rather simple. Given a 16K page we compress it using your favorite compression algorithm and write out the only the compressed data. After writing out the data we “punch a hole” to release the unused part of the original 16K block back to the file system. Let me illustrate with an example:

[DDDDDDDDDDDDDDDD] -> Compress -> [CCCCFFFFFFFFFFFF]

D – Data
F – Free …

The MariaDB project is pleased to announce a special preview release of MariaDB 10.0.9 with significant performance gains on FusionIO devices. This is is a beta-quality preview release.

Download MariaDB 10.0.9-FusionIO preview

Background

The latest work between MariaDB and FusionIO has focused on dramatically improving performance of MariaDB on the high-end SSD drives produced by Fusion-IO and at the same time delivering much better endurance for the drives themselves. Furthermore, FusionIO flash memory solutions increase transactional database performance. MariaDB includes specialized improvements for FusionIO devices, leveraging a feature of the NVMFS filesystem on these popular, high performance solid state disks. Using this feature, MariaDB 10 can eliminate some of the overhead within the InnoDB storage engine …