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Showing entries 1 to 10 of 13 3 Older Entries

Displaying posts with tag: Tips and Tricks (reset)

5 Database Insights Easy to See with VividCortex SaaS Monitoring
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There are manifold ways to collect, visualize, and analyze data… but not all methods are equally useful. VividCortex, however, is singular as a database-centric SaaS monitoring platform, and it's designed to provide you with powerful insights into your system that are both inherently actionable and unique. Within minutes of first booting up VividCortex, users frequently discover new aspects of their system. They understand it in brand new ways, just by viewing our app’s basic dashboards and metrics.

But that's just the start. Even beyond those initial revelations, there are many more powerful insights …

  [Read more...]
Fun with MySQL Cluster Memcached #1 - "ERROR: You can't mix -e with the old options"
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When using the bundled memcached that comes with MySQL Cluster and trying to set one of the 'classic' options along with passing the cluster connect string with -e you may end up getting the following message:

  ERROR: You can't mix -e with the old options

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Configuring email in the Cloud
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What a relief! A few simple configuration steps gives me new hope for coping with email.

It unlikely matters to you, but it does to me: My inbox is down to zero. That is, both my two inboxes are empty. I get work email to my address and private email to my, both of which have been suffering from bad email habits.

Inspired by years of discussions with Giuseppe Maxia, who is living proof that proper IT tools make geeks work smarter, faster and better, I bought the book "

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Nasty InnoDB regression in MySQL 5.5.25
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We just ran into a nasty InnoDB bug that only seems to exist in MySQL 5.5.25:

An InnoDB update that modifies a rows primary key can trigger some recursive behavior that creates new rows until all disk space is exceeded. This does not affect all primary key updates in general but only gets triggered when a few other conditions are also met, so you're not too likely to run into it, but if you do your mysqld server will waste a lot of IO bandwidth and storage space on this and will usually eventually run out of disk space.

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Adding a case insensitive, distinct unicode collation
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Every once in a while questions like the one in MySQL Bug #60843 or Bug #19567 come up:

What collation should i use if i want case insensitive behavior but also want all accented letter to be treated as distinct to their base letters?

or shorter, as the reporter of bug #60843 put it:

I need something like utf8_bin + ci

utf8_general_ci and utf8_unicode_ci unfortunately do not provide this behavior and utf8_bin is obviously not case insensitive.

…  [Read more...]
Using the MySQL stack trace to isolate bugs
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I came across an interesting error reported on #mysql the other day. When I went through it with the reporter it looks like we uncovered up to two bugs in InnoDB (or rather XtraDB as it was Percona Server). I thought it might be useful to go through the error message, including the stack trace, to show that you don't need to be a developer to track down some useful information.

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SkySQL Presents a New Community Resource
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SkySQL has always been committed to the MySQL® community and today we've unveiled a new resource page for the community. This is designed for the community to get a single point of information, assistance, and inspiration. While we are starting quite modestly it is up to you, the community, to make this the best resource for MySQL and related technologies.

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Consistent transactions between storage engines
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You may not realize it, but in MariaDB 5.2 and earlier and in MySQL up to version 5.5, START TRANSACTION WITH CONSISTENT SNAPSHOT does not give any guarantees of consistency between different storage engines.

For example, suppose you have two transactions which run in parallel:

Transaction T1:

    SET @t = NOW();
    UPDATE xtradb_table SET a= @t WHERE id = 5;
    UPDATE pbxt_table SET b= @t WHERE id = 5;

Transaction T2:

    SELECT t1.a, t2.b
      FROM xtradb_table t1 …
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How to produce a full stack trace for mysqld
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The information here was adapted from the AskMonty Knowledgebase.

There are two main parts to MariaDB and MySQL: The mysqld server and whatever client you use to interact with the server. The server is absolutely essential and must remain up and running. mysqld is normally very reliable, but there are rare occasions when it will fail. When mysqld fails hard (or core dump) it will, by default, write a stack trace in the 'hostname'.err file in the database directory. However, in some cases this is not enough to find out …

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The Importance of Planning
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Whenever I start a new project with MySQL or MariaDB I am tempted to jump in and start creating my schema and tables with nothing more than a basic outline of the requirements. Often the justification I give myself is that the sooner I have something up and running, the better off I'll be, and besides, there will be plenty of time to sort things out later. Even when I am absolutely sure my ad-hoc schema is only for "development purposes" and will "never ever be used in production" it often is.


A lot of grief can be avoided if time is taken right at the start, before any tables are defined, to plan. This is big picture time and every …

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Showing entries 1 to 10 of 13 3 Older Entries

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