You may have seen my posting regarding "eventual consistency" some
months ago, and you may have come to the conclusion that I was
insisting that a SQL based RDBMS is the way to go for just about
anything. Tell you what, that is not so. And nether am I against
using. say, MongoDB, where it is appropriate.
The whole deal with Eventual consistency is something that I am
still opposed to, I want to know if my data is consistent. And I
am not not sure that you cannot have a fully consistent,
distributed system either. But I guess that debate goes on. And I
still want my base data to be consistent. Like in
RDBMS-SQL-Foreign-keys-all-over-the-place-and-not-a-bl**dy-bit-lost-in-the-MyISAM-swamp
consistent. That is what I want the base data to look like. And
if there are compromises …
O’Reilly’s 2011 edition of the MySQL conference has an expanded agenda, with good representation from Postgres, CouchDB, MongoDB, and others. Take a look at the full schedule listing, which is being filled out as talks are approved and the speakers verify that they’ll give the session.
I am certainly looking forward to this year’s event. A tremendous amount of progress has landed in GA versions of open-source databases this year. To name just a couple, there’s a new version of Postgres (9.0) with built-in replication and many more improvements; there’s MySQL 5.5 GA; there’s the HandlerSocket NoSQL interface to MySQL; Drizzle has a beta release; and the list goes on. I believe that this conference will have balanced and representative coverage of what’s really important to users. …
[Read more]This month’s Maatkit release has some nice new features and improvements to mk-query-digest. There is one that deserves its own blog post: EXPLAIN sparklines.
A “sparkline” is a simple type of chart that conveys important information without the details. We added a kind of ASCII sparkline to mk-query-digest to convey important information about the query’s EXPLAIN plan so you can see if the query is “bad” or not. It is kind of a cryptic geek code that you will need some help decoding. It’s intentionally compact, so that it can fit in the “profile” that mk-query-digest prints out from a normal report.
Here is an example of the profile report:
# Profile
# Rank Query ID Response time Calls R/Call Apdx V/M EXPLAIN Item
# ==== ================== ================ ===== ======== ==== ===== ======= =====
# 1 0x808CDA06B6EB3D5A 0.0141 …The art of simplicity is a puzzle of complexity. (Douglas Horton)
No puzzle looks simpler than a Sudoku. But behind the very few rules of this game hides enormous complexity. It’s now proved that there are 6670903752021072936960 different grids for a standard 9×9 Sudoku. More refinements and subtleties taking symmetries into account have been examined as well as other variants of Sudoku. Solving strategies have been studied inside out, enumerated and refined. Sudoku grids and Latin squares have kept mathematicians busy for a long time and lots of hidden patterns and complex concepts still remain to be discovered. This little game is a treasure island for mathematicians and developers : we only need to dig deep enough and long enough…
This …
[Read more]I am preparing a series of posts related to Sudoku. I am revisiting the “SQL only” solution I posted somewhere else a long time ago… This time, we’ll get serious and optimize everything we can! This lemon will be squeezed to the maximum!
Start your Pharo image (not mandatory since I will provide all necessary SQL scripts) and MySQL server as we’ll try to solve some Sudoku puzzles only with one SQL statement (no stored procedures or functions)!
Part 1 coming soon!
I’m back in the blogosphere!
This blog will focus on Smalltalk (mostly Pharo, Squeak, Dolphin, VAST and VW), databases (usually MySQL, PostgreSQL, SQL Server, DB2, InterBase and Firebird), algorithms and open source tools. I’ll throw in some literature, music and mathematics occasionally.
Requirements to enjoy this blog : an interest in problem solving, a database and a Smalltalk environment!
There have been a few great blog posts recently from MySQL bloggers about Postgres, and vice versa, with good comments and follow-on from the real experts in both systems. I think this is wonderful. Learning how other databases solve hard problems is highly educational, especially because ACID databases face some of the hardest problems in computing. Making MySQL better is good for PostgreSQL. The reverse is just as true. And we should also be learning from SQLite, and CouchDB, and others who have overcome tough technical hurdles, built successful companies, created thriving and enthusiastic communities, or whatever their success has been.
Related posts:
[Read more]
Alaric
Snell-Pym discusses why choose between SQL and NoSQL? Why can't
you use both in your infrastructure?
"NoSQL engines abandon SQL for the chance to have more flexible
data models and softer semantics for update operations - but they
also abandon it because it’s a lot of work to implement. And,
creating a new database from scratch, they’re keen on solving the
interesting hard problems (such as replicated data storage),
rather than following the well-trodden path of writing SQL
parsers and query planners, with a few decades of catching up
with the competition ahead of them."
MyQuery 4version 3.4.1 is now released on Sourceforge: http://sourceforge.net/projects/myquery/. This is
a pretty minor release with just a few fixes, but the first of
them pretty significant:
- Windows 7 User Access Control (UAC) issue fixed - When running on Windows 7, the Windows UAC would prohibit MyQuery from starting, complaining about registry access. For once, this was not yet another UAC annoyance, but an actual bug that I hadn't caught before. Now, this should work OK even on Windows 7.
- SQL Statement normalization issues - The SQL Statements dialog got statements wrong at times, and could cause a crash. This was due to a bug in the normalization of SQL Statements and this is now fixed, including refining the normalization a bit.
- Optionally Show SQL SELECT tool output vertically - This will turn the output from the SQL command in …
The more I go through others SQL, there are some common mistakes that I see developers making over and over again, so I thought why not start a series of tips that can help developers optimize their queries and avoid common pitfalls. So this post is a part of that series of tips, and this is the first tip "Avoid using a wild card character at the start of a LIKE pattern".