I may retract this post, I may have been way too incorrect here, not sure yet.

Hash maps were invented sixty years ago, apparently. MySQL reinvented them.

Original idea was too fancy and too good, I guess. It allowed very cheap access to data, if you knew a key, and it achieved that by having a hashing function, which is used to pick a slot, then going directly to that slot. It is used in your computer all the time. ALL THE TIME.

They are so fast and useful, that they are always treated as building blocks. There have been various iterations later, to support concurrency, hashing functions evolved, etc, but the premise was the same.

If we look at the dictionary, it is obvious that “hash” is:

a mixture of jumbled incongruous things; a mess.

Yes, MySQL, the whole concept is to have as messy as possible data …

To support the growing emphasis on real-time operations, MySQL is releasing a new MySQL Applier for Hadoop to enable the replication of events from MySQL to Hadoop / Hive / HDFS (Hadoop Distributed File System) as they happen. The MySQL Applier for Hadoop complements existing batch-based Apache Sqoop connectivity. This developer article gives you everything you need to get started in implementing real-time MySQL to Hadoop integration.

A few years ago, I asked to check with me in the long (very long) change history of MySQL 5.5 documentation what are the changes in relation to the SQL syntax.
Chris Calender helped me to retrieve a list of the main changes, thanks again Chris.

Today, I would like to share this list with you.
It is simply a curated transcript of what you might find in the documentation but I’m sure it can help some of you.
 

INTO clause in nested SELECT statements

 
Previously, the parser accepted an INTO clause in nested SELECT statements, which is invalid because such statements must return their results to the outer context. As of MySQL 5.5.3, this syntax is no longer permitted and statements that use it must be changed.
 

Table aliases in DELETE statements

 
In MySQL 5.5.3, several changes …

We were delighted last week to find out that we’d been named one of the ‘2013 Top 100 Europe’ winning companies by the Red Herring editorial team. Congratulations to all companies involved!

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We were delighted last week to find out that we’d been named one of the ‘2013 Top 100 Europe’ winning companies by the Red Herring editorial team. Congratulations to all companies involved!

read more

This article inspired by benchmark results published by Alexey @Percona related to the "trx_list" modifications came with latest Percona Server 5.5. I was particularly curious about this feature, because the exactly the same solution was rejected by Sunny two years ago while analyzed this kind of problems (described within presented bug report and others)..

But well, one real test result is better than many discussions, so let's see what kind of results I will get on my own server. I'll test the same OLTP_RO Point-Select workload using 8 tables (by running 8 Sysbench processes in parallel). I'd say that this kind of load was initially pretty …

MySQL 5.6 @ Facebook development tree

Steaphan is a hero (well, everyone else on database engineering team are too) and he is driving efforts to publish MySQL 5.6 changes we’re making to the open. Now they’re on the github (yet not in production, we’re in active testing though with our workloads).

I recently wrote about Where are they now: MySQL Storage Engines and The MERGE storage engine: not dead, just resting…. or forgotten. Today, it’s the turn of the MEMORY storage engine – otherwise known as HEAP.

This is yet another piece of the MySQL server that sits largely unmaintained and unloved. The MySQL Manual even claims that it supports encryption… with the caveat of having to use the SQL functions for encryption/decryption rather than in the engine itself (so, basically, it supports encryption about as much as every other engine does).

The only …

Stewart Smith recently questioned the current relevance of the MERGE storage engine, and it prompted me to finish a similar recent exercise I’ve been thinking about related to MySQL clients (UPDATE: and programs).  This originally came up when I listed the contents of the MySQL bin directory:

D:\mysql-advanced-5.6.11-win32>dir bin\*.exe
Volume in drive D is Data
Volume Serial Number is 4015-B2FF

Directory of D:\mysql-advanced-5.6.11-win32\bin

04/05/2013  06:52 AM           123,392 echo.exe
04/05/2013  06:53 AM         4,696,064 innochecksum.exe
04/05/2013  06:54 AM         5,084,672 myisamchk.exe
…