In a previous thread pool post, I mentioned that in Percona Server we used an open source implementation of MariaDB’s thread pool, and enhanced/improved it further. Below I would like to describe some of these improvements for transactional workloads.

When we were evaluating MariaDB’s thread pool implementation, we observed that it improves scalability for AUTOCOMMIT statements. However, it does not scale well with multi-statement transactions. The UPDATE_NO_KEY test which was run as an AUTOCOMMIT statement and inside a transaction gave the following results:

After analysis, we identified the major cause of that inefficiency: …

I currently have on a MySQL 5.6 database using innodb_file_per_table the following individual tablespace file.

schema/FTS_00000000000001bb_BEING_DELETED.ibd

The schema is all InnoDB tables, and there ARE NO Full Text Indexes. I cannot comment on if a developer has tried to create one previously.
I am none the wiser in explaining the ongoing use of these files, or if it can be/should be deleted.

On closer inspection there are infact a number of FTS files.

$ ls -al FTS*
-rw-r----- 1 mysql mysql 98304 Jan 29 16:21 FTS_00000000000001bb_BEING_DELETED_CACHE.ibd
-rw-r----- 1 mysql mysql 98304 Jan 29 16:20 FTS_00000000000001bb_BEING_DELETED.ibd
-rw-r----- 1 mysql mysql 98304 Jan 29 16:26 FTS_00000000000001bb_CONFIG.ibd
-rw-r----- 1 mysql mysql 98304 Jan 29 16:21 FTS_00000000000001bb_DELETED_CACHE.ibd
-rw-r----- 1 mysql mysql 98304 Jan 29 16:00 FTS_00000000000001bb_DELETED.ibd
-rw-r----- 1 mysql mysql 98304 Jan 29 16:20 …

New version of JSON UDF functions 0.2.2 have been just released. It is last maintenance release of 0.2 series. However it contains two new features:

JSON_VALID now accepts array as a root element of the JSON document (Bug#70567/17583282)

JSON functions can now be installed and uninstalled using a script (Bug#71263/18022788 Easy installation sql script).

This feature is Community contribution. Thank you, Daniel van Eeden!

This release also contains following bug fixes:

71050/17882710 json_extract returning same column twice if key names are not fully distinct. (Fixed for JSON_EXTRACT, JSON_CONTAINS_KEY, JSON_APPEND, JSON_REMOVE, JSON_REPLACE, JSON_SET) …

The MariaDB project is pleased to announce the immediate availability of MariaDB 5.5.35. This is a Stable (GA) release. See the Release Notes and Changelog for detailed information on this release and the What is MariaDB 5.5? page in the MariaDB Knowledge Base for general information about the MariaDB 5.5 series.

Download MariaDB 5.5.35

Release Notes Changelog …

In our practice we often see that MySQL performance optimization is done in a sort of “black magic” way. A common opinion is: “If there is a performance problem – then it must be a database issue, because what else could it be? And if this is a database issue, then it must involve IO problems because the reason for a slow database is always a slow IO…”  Following this logic might actually give a result, but achieving a fully successful resolution would require magic.

At Percona we use a different approach. Performance optimization should not be based on guesses, but exact measurements. In application to databases, I described previously, we use queries as units of work. And a proper measurement of these units is the first important task in …

The latest pip versions will fail on you when the packages it needs to install are not hosted on PyPI. When you try to install MySQL Connector/Python the usually way, you get following message is:

shell> pip install mysql-connector-python
  Could not find any downloads that satisfy the requirement 
    mysql-connector-python
  Some externally hosted files were ignored 
    (use --allow-external mysql-connector-python to allow).

I have updated the download URL to include the MD5 checksum, and MySQL Connector/Python should now install using pip using following command:

shell> pip install --allow-external mysql-connector-python \
  mysql-connector-python

Yes, you have to repeat the mysql-connector-python name. …

Atos is an international information technology services company with annual revenue of EUR 8.8 billion and 77,100 employees in 52 countries. Serving a global client base, it delivers IT services in 3 domains, Consulting & Technology Services, Systems Integration and Managed Services & BPO and transactional services through Worldline.

In 2009 Atos was asked to drastically reduce the costs of the UCS application (Universal Clearing System): the compensation engine for the Euronext Cash (stocks and bonds) and derivatives markets in the Euro zone. In the financial sector, clearing is exercised by aggregating all purchases and sales by the type of product/assets held by each account holder, resulting in a balance of net payables or receivables as well as the net flows of securities delivered or received.

Challenges 

• Migrate from a proprietary HP NonStop-SQL/MP environment towards an open source …

I write this post over to have a quick access to this tutorial than to promote the blog. The problem For Several times this has happened to me, always install a new server, or personal machine. I install mysql ,… Continue Reading →

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Over the years you collect datasets you have created for various types of testing, seeding databases etc. I have always thought one needs to better manage this for future re-use. Recently I wanted to do some “Big Data” playing and again that question of what datasets can I use let me to review the past collated list at Seeking public data for benchmarks.

The types of things I was wanting to do lead me to realize a lot of content is “public domain” and Project Gutenberg is just one great source of text in multiple languages. This was just one aspect of my wish list but text based data is used from blogs, comments, articles, microblogs etc, and multiple languages was important from some text analysis.

With a bit of thinking about the building blocks, I created …

Troubleshooting MySQL on Amazon can be a real test of patience. There are quite a few different things to watch out for in terms of connectivity & networking. Sometimes a checklist can help. Join 16,000 others and follow Sean Hull on twitter @hullsean. Here’s my exhaustive list of things that can block you. 1. Be […]