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10 Newer Entries Showing entries 31 to 40 of 1014 10 Older Entries

Displaying posts with tag: sql (reset)

New! MySQL Utilities release-1.4.2-RC
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The MySQL Utilities Team is pleased to announce the latest release candidate (RC) release of MySQL Utilities. This release includes a number of improvements for useabilty, stability, and a few enhancements. A complete list of all improvements can be found in our release_notes.

New Utilities!
We have also included two new utilities.

  • The mysqlrplsync utility was added, which checks data consistency between servers in a replicated setup. 
  • The mysqlrplms utility was added, which provides …




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Announcing MySQL Connector/Arduino 1.0.2 Beta
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I've completed a new release of the Connector/Arduino! The new release contains some major improvements with memory handling.

  • The library has been trimmed to save memory.
    • Static strings moved to PROGMEM strings
    • Unused structures removed (e.g. ok_packet)
    • Moved two more methods to optional compilation
  • The WITH_SELECT is turned *OFF* by default. If you want to use select queries, be sure to uncomment this in the mysql.h file.
  • Added a CHANGES.txt file to track changes between releases.


Memory, What …


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Book review: Getting started with MariaDB
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Getting started with MariaDB, by Daniel Bartholomew, is a good book for people who wants to approach MariaDB without knowing MySQL. While this book covers all basic topics, it provides a vast overview of what MariaDB is and can do. In other words: the text is …

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Inner vs. Outer Joins
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I want to teach you the difference between an inner and an outer join. We first need to think about what a join is. Simply, it’s when you combine two tables to make a new one. You’re not physically creating a new table when you join them together, but for the purposes of the query, you are creating a new virtual table. Every row now has the columns from both tables. So if TableA has columns Col1 and Col2 and TableB has columns Col3 and Col4, when you join these two tables, you’ll get Col1, Col2, Col3, and Col4. Just as with any query, you have the option of including all columns or excluding some, as well as filtering out rows.

Inner join. A …

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WITHer Recursive Queries?
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Over the past few years, we’ve seen MySQL technology advance in leaps and bounds, especially when it comes to scalability. But by focusing on the internals of the storage engine for so long, MySQL has fallen behind regarding support for advanced SQL features.

SQLite, another popular open-source SQL database, just released version 3.8.3, including support for recursive SQL queries using the WITH RECURSIVE syntax, in compliance with SQL:1999.

Why is this significant? It means that MySQL is now the …

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Unittesting your indexes
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During FOSDEM PGDay I watched the "Indexes: The neglected performance all-rounder" talk by Markus Winand. Both his talk and the "SQL Performance Explained" book (which is also available online) are great.

The conclusion of the talk is that we should put more effort in carefully designing indexes. But how can we make sure the indexes are really used now and in the future? We need to write some tests for it.

So I wrote a small Python script to test …



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MariaDB 10: Performing fast & inaccurate statistics
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As I already wrote, COUNT(*) can be expensive in InnoDB, because this value is not stored in indexes. Some other storage engines may not store that value. Also, COUNT(), MAX(), MIN() are immediate only if executed on an indexed column. But we don’t want too many indexes, and some exotic storage engines do not support indexes – thus, we may need to execute an aggregate function on a non-indexed column.

Now, the question is: do you really need such values to …

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Immutability, MVCC, and garbage collection
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Not too long ago I attended a talk about a database called Datomic. My overall impressions of Datomic were pretty negative, but this blog post isn’t about that. This is about one of the things the speaker referenced a lot: immutability and its benefits. I hope to illustrate, if only sketchily, why a lot of sophisticated databases are actually leaps and bounds beyond the simplistic design of such immutable databases. This is in direct contradiction to what proponents of Datomic-like systems would have you believe; they’d tell you that their immutable database …

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New! MySQL Utilities release-1.3.6 GA
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The MySQL Utilities Team is pleased to announce the latest GA release of MySQL Utilities. This release includes a number of improvements for usability, stability, and a few enhancements. We have also included a performance upgrade for exporting, importing, and copying databases.

Improvements
The following highlights a few of the more significant improvements.

* mysqldbexport, mysqldbimport, and mysqldbcopy have multiprocessing support that allows for much improved performance
* mysqlfrm can now generate a .frm file with storage engine substitution
* Mac OS X packages added!
* …







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How is the MariaDB Knowledge Base licensed?
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I clicked around for a few moments but didn’t immediately see a license mentioned for the MariaDB knowledgebase. As far as I know, the MySQL documentation is not licensed in a way that would allow copying or derivative works, but at least some of the MariaDB Knowledge Base seems to be pretty similar to the corresponding MySQL documentation. See for example LOAD DATA LOCAL INFILE: MariaDB, MySQL. …

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10 Newer Entries Showing entries 31 to 40 of 1014 10 Older Entries

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