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Displaying posts with tag: sql (reset)

How much memory should we assign to MariaDB?
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How much memory should we assign to MariaDB?

Before answering, I’ll show you a procedure I use to get the amount of memory I’m using. See the comments to make it work on Oracle MySQL.

CREATE PROCEDURE _.show_buffers()
        CONTAINS SQL
        COMMENT 'Show information about buffers size'
BEGIN
        SET @memory_per_thread := (
                          @@global.read_buffer_size
                        + @@global.read_rnd_buffer_size
                        + @@global.sort_buffer_size
                        + @@global.thread_stack
                        + @@global.join_buffer_size
                        + …

  [Read more...]
Creating JSON documents with MariaDB
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You probably know about two MariaDB great features: Dynamic Columns and Virtual Colums. I don’t think that we already found all possible use cases for them: more ideas will come in the future, and hopefully someone will write about them. Here, I will describe a use case which involves both Virtual Columns and Dynamic Columns.

Now, suppose that we have relational data in MariaDB, and we want to …

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On Hadoop RDBMS. Interview with Monte Zweben.
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“HBase and Hadoop are the only technologies proven to scale to dozens of petabytes on commodity servers, currently being used by companies such as Facebook, Twitter, Adobe and Salesforce.com.”–Monte Zweben.

Is it possible to turn Hadoop into a RDBMS? On this topic, I have interviewed Monte Zweben, Co-Founder and Chief Executive Officer of Splice Machine.

RVZ

Q1. What are the main challenges of applications and operational analytics that support real-time, interactive queries on data updated in real-time for Big Data?

…  [Read more...]
The Road to MySQL 5.6: Default Options
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When you're testing out a new version of MySQL in a non-production environment there is a temptation to go wild and turn on all kinds of new features.  Especially if you're reading the changelogs or the manual and scanning through options.  You want to start with the most reasonable set of defaults, right?  Maybe you're even doing benchmarks to optimize performance using all the new bells and whistles.

Resist the temptation!  If your goal is to upgrade your production environment then what you really want is to isolate changes.  You want to preform the upgrade with as little to no impact as possible.  Then you …

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How to use value from row derived column from a table in another query?
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SELECT...INTO can be used to store the single row column result value from a query to be used in another query depending on that value.

"accounts" table

+--------------+-------------+------+-----+---------+----------------+
| Field        | Type        | Null | Key | Default | Extra          |
+--------------+-------------+------+-----+---------+----------------+
| account_id   | …






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Use of loops in MySQL stored procedures
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Loops -> Repetitive tasks

3 types of loops in MySQL stored program:
- Simple loop using LOOP and END LOOP clauses
- WHILE and END WHILE clauses that runs while a condition is true
- REPEAT  and UNTIL clauses that runs until a condition is true



Termination of loop -> LEAVE statement.

I will demonstrate the use of loops the simple loop way.














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Using conditional expressions inside MySQL Stored Procedure
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Sometimes there is need to use conditional expression inside stored procedure to control the flow of execution.
We can use IF or CASE statements for this.


Below is a stored procedure to check the performance of a student based on its score.
Store the below stored procedure in a file called get_performance.sql

DELIMITER $$

DROP PROCEDURE IF EXISTS get_performance$$

CREATE PROCEDURE …










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How to use and get output arguments in stored procedure using OUT parameter mode?
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It is sometimes required to get the result of a stored procedure in a variable which can be used later or to output the result.

To do so, we can use the "OUT" parameter mode while defining stored procedures.

In the below section, we will be writing a stored procedure to get the square root of a number returned in an output variable provided by us.



Stored Procedure Definition:

Store the below stored procedure in a file named …









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We’re Hiring! And Looking to Add More 9s to the Severalnines Team!
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August 15, 2014 By Severalnines

 

 

We're looking for an energetic and talented web developer to join our small but agile web team. This position is full-time and pay is negotiable. The hours are flexible and work can be done remotely.

 

Severalnines is a self-funded startup with a dozen employees; headquartered in Stockholm, Sweden and with a globally distributed, home-office based team. We provide automation and management software for database clusters. Our …

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Which Compression Tool Should I Use for my Database Backups? (Part I: Compression)
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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 …

  [Read more...]
Showing entries 1 to 10 of 1006 10 Older Entries

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