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Showing entries 1 to 19

Displaying posts with tag: metadata (reset)

Tracking Metadata Locks (MDL) in MariaDB 10.0
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I recently blogged about tracking metadata locks in the latest MySQL, and now I want to discuss how to track these metadata locks in MariaDB.

In MySQL 5.7, there is a table named `metadata_locks` added to the performance_schema (performance_schema must be enabled *and* the metadata_locks instrument must be specifically enabled as well.

In the MariaDB 10.0 implementation (as of 10.0.7), there is a table named METADATA_LOCK_INFO added to the *information_schema*. This is a new plugin, so the plugin must be installed, but that is very simple with:

INSTALL SONAME 'metadata_lock_info';

Then, you will have the table.

To see it in action:

Connection #1:

mysql> create table t (id int) engine=myisam;
mysql> begin;
mysql> select * from t;

Connection #2:

mysql> alter table t
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Tracking Metadata Locks (MDL) in MySQL 5.7
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I’ve blogged about metadata locks (MDL) in the past (1 2 3) and in particular discussed how best to track them down and troubleshoot threads stuck waiting on metadata locks.

If you’ve had any experience with these, you’ll know finding them isn’t always the most straight-forward task.

So I was glad to see metadata lock instrumentation added to MySQL 5.7.3 as part of performance_schema, which makes tracking these down a breeze! (Note this is only in 5.7.3 currently, and therefore is some time from being GA as of today)!

To use these, performance_schema must be enabled (i.e., performance_schema=1 in your config file).

But, also, the metadata_locks instrument is disabled by default, so even if you enable the

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Data Modeling
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Dear data integration fans,

I’m a big fan of “appropriate” data modeling prior to doing any data integration work.  For a number of folks out there that means the creation of an Enterprise Data Warehouse model in classical Bill Inmon style.  Others prefer to use modern modeling techniques like Data Vault, created by Dan Linstedt.  However, the largest group data warehouse architects use a technique called dimensional modeling championed by Ralph Kimball.

Using a modeling technique is very important since it brings structure to your data warehouse.  The techniques used, when applied correctly of-course, are

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Viewing RMAN jobs status and output
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Yesterday I was discussing with a fellow DBA about ways to check the status of existing and/or past RMAN jobs. Good backup scripts usually write their output to some sort of log file so, checking the output is usually a straight-forward task. However, backup jobs can be scheduled in many different ways (crontab, Grid Control, Scheduled Tasks, etc) and finding the log file may be tricky if you don’t know the environment well.
Furthermore, log files may also have already been overwritten by the next backup or simply just deleted. An alternative way of accessing that information, thus, may come handy.

Fortunately, RMAN keeps the backup metadata around for some time and it can be accessed through the database’s V$ views. Obviously, if you need this information because your database just crashed and needs to be restored, the method described here is useless.


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Dynamic de-normalization of attributes stored in key-value pair tables
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Dear Kettlers,

A couple of years ago I wrote a post about key/value tables and how they can ruin the day of any honest person that wants to create BI solutions.  The obvious advice I gave back then was to not use those tables in the first place if you’re serious about a BI solution.  And if you have to, do some denormalization.

However, there are occasions where you need to query a source system and get some report going on them.  Let’s take a look at an example :

mysql> select * from person;
+----+-------+----------+
| id | name  | lastname |
+----+-------+----------+
|  1 | Lex   | Luthor   |
|  2 | Clark | Kent     |
|  3 | Lois  | Lane     |
+----+-------+----------+
3 rows in set (0.00 sec)

mysql> select * from person_attribute;
+----+-----------+---------------+------------+
| id | person_id | attr_key     
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Parse nasty XLS with dynamic ETL
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Dear Kettle friends,

Last year, right after the summer in version 4.1 of Pentaho Data Integration, we introduced the notion of dynamically inserted ETL metadata (Youtube video here).  Since then we received a lot of positive feedback on this functionality which encouraged me to extend it to a few more steps. Already with support for “CSV Input” and “Select Values” we could do a lot of dynamic things.  However, we can clearly do a lot better by extending our initiative to a few more steps: “Microsoft Excel Input” (which can also read ODS by the way), “Row Normalizer” and “Row De-normalizer”.

Below I’ll describe an actual (obfuscated) example that you will probably recognize as it is equally hideous as simple in it’s horrible complexity.

Take a look at this file:

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Drizzle metadata tables
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Giuseppe has a great post about the Evolution of MySQL metadata, and I thought I’d have a look at what we have in Drizzle. It’s pretty easy to work out how many tables are in each schema, we just query the standard INFORMATION_SCHEMA.TABLES view:

drizzle> select table_schema,count(table_name)
    ->  from information_schema.tables
    -> group by table_schema;
+--------------------+-------------------+
| table_schema       | count(table_name) |
+--------------------+-------------------+
| DATA_DICTIONARY    |                53 |
| INFORMATION_SCHEMA |                20 |
+--------------------+-------------------+
2 rows in set (0 sec)

In Drizzle it’s important to note that

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Evolution of MySQL metadata
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I was looking at the latest MySQL versions, and I happened to notice that there has been a great increment in the number of metadata tables, both in the information_schema and performance_schema databases. So I made a simple count of both schemas in the various versions, and draw a graph. The advance looks straightforward.

versionInformation_schemaperformance_schema5.0.921705.1.542805.1.54 with innodb plugin3505.5.837175.6.24823


The difference between 5.0 and 5.6 is staggering. We came from 17 to 71 metadata total tables. A stacked bar chart helps visualize the changes.



I noticed, BTW, that








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INFORMATION_SCHEMA tables are case sensitive
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I wanted to get examples of some of the extra information that the Percona server has in its INFORMATION_SCHEMA metadata, and in doing so, I stumbled across an interesting MySQL bug/feature/point — INFORMATION_SCHEMA tables (which are actually system views) are case sensitive when used in comparisons:

mysql> use information_schema;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql>  select @@version;
+--------------------+
| @@version          |
+--------------------+
| 5.1.36-xtradb6-log |
+--------------------+
1 row in set (0.00 sec)

mysql> use information_schema;
Database changed
mysql> show tables like 'innodb%';
Empty set (0.00 sec)

mysql>  show tables like 'INNODB%';

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Log Buffer #150
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This is the 150th edition of Log Buffer, the weekly review of database blogs. Someone accidentally left Dave Edwards‘ cage unlocked, and he escaped, thus leaving me with the pleasurable duty of compiling the 150th weekly Log Buffer.

Many people other than Dave are finding release this week. Giuseppe Maxia explains some details of MySQL’s New Release Model. Andrew Morgan announces a New MySQL Cluster Maintenance Release. Aleksandr Kuzminsky of the MySQL Performance Blog releases

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New in MySQL 5.1: Sheeri’s Presentation
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In a nutshell: What’s New in MySQL 5.1.

Release notes: Changes in release 5.1.x (Production).

And yes, very early on (at about two minutes in), I talk about my take on Monty’s controversial post at Oops, we did it again.

To play the video directly, go to http://technocation.org/node/663/play. To download the 146 Mb video to your computer for offline playback, go to http://technocation.org/node/663/download. The slides can be downloaded as a

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Using Plugins in MySQL™ 5.1
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[HoneyMonitor is a GUI for MySQL™. Server Administration, Database and Database Objects Administration, Code Development, Server Monitoring, Performance Monitoring, Performance Auditing. Read more on http://www.honeysoftware.com/]

This is a short tutorial on the features implemented in HoneyMonitor for the use and administration of Plugins. It could be useful for Users who are new to the product and want to get start with it or to whom want to learn the basis of Plugins in MySQL™ 5.1

More details on the HoneyMonitor Reference Manual at http://www.honeysoftware.com/honeymonitor/doc.

Contents

  • Introduction
  • Plugins Metadata
  • Retrieving the list of Plugins
  • The Plugins
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Using Federated Servers in MySQL™ 5.1
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[HoneyMonitor is a GUI for MySQL™. Server Administration, Database and Database Objects Administration, Code Development, Server Monitoring, Performance Monitoring, Performance Auditing. Read more on http://www.honeysoftware.com]

This is a short tutorial on the features implemented in HoneyMonitor for the use and administration of Federated Servers . It could be useful for Users who are new to the product and want to get start with it or to whom want to learn the basis of Federated Servers in MySQL™ 5.1

More details on the HoneyMonitor Reference Manual at http://www.honeysoftware.com/honeymonitor/doc.

 

Contents

  • Introduction
  • Federated Server Metadata
  • Retrieving the list of
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[HoneyMonitor Tutorial] Brief Introduction to the Server Objects List
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[HoneyMonitor is a GUI for MySQL™. Server Administration, Database and Database Objects Administration, Code Development, Server Monitoring, Performance Monitoring, Performance Auditing. Read more on http://www.honeysoftware.com]

This is a short tutorial on the Server Objects List included in HoneyMonitor. I am writing it because I will reference it in some posts I am going to write in the next weeks. Furthermore, it could be useful for Users who are new to the product and want to get start with it.

More details on the HoneyMonitor Reference Manual at http://www.honeysoftware.com/honeymonitor/doc.

 

Contents:

  • Introduction
  • Connections Tree
  • Metadata Catalog
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Pentaho changes
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I’m back at my favorite spot at the Orlando airport:

This week has gone bye so fast it’s kinda scary.  I got dragged into one meeting after another design session after another knowledge transfer opportunity for 5 days in a row.  After our long working days, the discussions and talks just continued over dinner and beers.

It was great to meet everyone and as always we had a good time around the office and at the Ale House.  I even managed to stay sober this time around.  Well at least most of the time.

As always, the thing that struck me the most was how fast Pentaho changes.  It’s almost like visiting a different company every time I drop in.  Since I don’t see the day-to-day changes around the office, the difference between the first time I visited (15 people) and now (70+) is striking.  The office

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Discovering FALCON Metadata in MySQL® v. 6.0.5-alpha
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Introduction
MySQL® 6.0.5-alpha, the latest version of the 6.x branch of the Database Server, is available for download from the SUN|MySQL Web Site.

Metadata (data about the data) are very important, especially for software developers. In this article we will see what’s new in FALCON metadata handling doing some comparison with the old 6.0.4-alpha version.

New tables in the `information_schema` database
As you know, the source for metadata is the database `information_schema`. To start, let’s see which tables related with FALCON metadata are included in that database:

mysql> SELECT VERSION();
+—————————+
|



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Describing outer joins in metadata
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Dear Metadata fans,

It’s been a while that I blogged about Pentaho Metadata. This is undeservedly so because the last couple of months, a lot of things have been moving. Most of that is not really visible to the end-user. The GUI part of the metadata suite was attacked last year and doesn’t really need all that much work. What we have been doing is extending the underlaying architecture by making it more flexible, more robust and easier to program from an API viewpoint. Most of that work has been in the capable hands of Pentaho rock star Will Gorman. The work he did last year for example was building in support for libformula (Open Office formula) by Pentaho reporting wizard Thomas Morgner.

Lately, Will and I started on the next

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Pentaho reference case
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Thought I’d mention that a new case study featuring Pentaho and Kettle showed up over at the Database Trends and Applications. The name of the paper is called “Loma Linda University Health Care Deploys Pentaho BI” (PDF).

To quote :

With commercial products you don’t know if you are getting what you want, but with open source you can create proofs-of-concept. And the TCO is so much lower.

Until next time!

Matt

Pentaho metadata
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Today Pentaho released the first milestone of “Pentaho metadata” as a new core utility to make the life of BI professionals yet a little bit easier.

As you can see in the screenshot of the Pentaho metadata editor above, we offer a solution that bridges the gap between the worlds of the relational databases and business information. Here are a few of the key points that differentiate Pentaho metadata from the competition:

  • Completely open
    • Released under an open source license (Mozilla Public License v1.0)
    • Persisting in the Common Warehouse Metamode, a recognised industry standard, potentially allowing for easier interoperability with
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Showing entries 1 to 19

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