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Showing entries 1 to 10 of 34734 10 Older Entries
InnoDB checkpoint strikes back
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In my recent benchmarks for MongoDB, we can see that the two engines WiredTiger and TokuMX struggle from periodical drops in throughput, which is clearly related to a checkpoint interval – and therefore I correspond it to a checkpoint activity.

The funny thing is that I thought we solved checkpointing issues in InnoDB once and for good. There are bunch of posts on this issue in InnoDB, dated some 4 years ago.  We did a lot of research back then working on a fix for Percona Server

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Deploy Asynchronous Replication Slave to MariaDB Galera Cluster 10.x using ClusterControl
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Combining Galera and asynchronous replication in the same MariaDB setup, aka Hybrid Replication, can be useful - e.g. as a live backup node in a remote datacenter or reporting/analytics server. We already blogged about this setup for Codership/Galera or Percona XtraDB Cluster users, but master failover did not work for MariaDB because of its different GTID approach. In this post, we will show you how to deploy an asynchronous replication slave to MariaDB Galera Cluster 10.x (with master failover!), using GTID …

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How to hire for Infrastructure Operations Engineers
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I have been working for a very large Australian website for over six years and during this period have been fortunate enough to hire many Infrastructure Operations Engineers that now work for that company. I want to detail the evolution of the hiring process and what I have driven it to over the last six years.
How was I hiredThis is the interview process I went through at my current company:

  • A technical and cultural pre-screening from a recruiter
  • A short phone interview with a small set of adhoc questions around technical skill set. How does DNS work?
  • An hour long face to face interview with the …

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on ORDER BY optimization | Domas Mituzas
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http://dom.as/2015/07/30/on-order-by-optimization/

An insightful exploration by Domas (Facebook) on how some of the MySQL optimiser’s decision logic is sometimes naive, in this case regarding ORDER BY optimisation.

Quite often, “simple” logic can work better than complex logic as chasing all the corner cases can just make things worse – but sometimes, logic can be too simple.

Everything must be made as simple as possible, but no simpler.
— Albert Einstein / Roger Sessions

Log Buffer #434: A Carnival of the Vanities for DBAs
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This Log Buffer Edition throws spotlight on some of the salient blog posts from Oracle, SQL Server and MySQL.

Oracle:

  • STANDARD date considerations in Oracle SQL and PL/SQL
  • My good friend, Oracle icon Karen Morton passed away.
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MariaDB automatic failover with MaxScale and MariaDB Replication Manager
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Fri, 2015-07-31 12:14guillaumelefranc

Mandatory disclaimer: the techniques described in this blog post are experimental, so use at your own risk. Neither me nor MariaDB Corporation will be held responsible if anything bad happens to your servers.

Context

MaxScale 1.2.0 and above can call external scripts on monitor events. In the case of a classic Master-Slave setup, this can be used for automatic failover and promotion using MariaDB Replication Manager. The following use case is exposed using three MariaDB servers (one master, two slaves) and a MaxScale server. Please refer to my …

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MySQL QA Episode 10: Reproducing and Simplifying: How to get it Right
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Welcome to the 10th episode in the MySQL QA series! Today we’ll talk about reproducing and simplifying: How to get it Right.

Note that unless you are a QA engineer stuck on a remote, and additionally difficult-to-reproduce or difficult-to-reduce bug, this episode will largely be non-interesting for you.

However, what you may like to see – especially if you watched episodes 7 (and possibly 8 and 9) – is how reducer automatically generates handy start/stop/client (cl) etc. scripts, all packed into a handy bug tarball, in combination with the reduced SQL testcase.

This somewhat separate part is covered …

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Shinguz: Max_used_connections per user/account
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Taxonomy upgrade extras: max_used_connectionsuseraccountconnectionconfiguration

How many connections can be opened concurrently against my MySQL or MariaDB database can be configured and checked with the following command:

SHOW GLOBAL VARIABLES LIKE 'max_connections';
+-----------------+-------+
| Variable_name …
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on ORDER BY optimization
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Generally in MySQL we send queries massaged to a point where optimizer doesn’t have to think about anything. In our major user database environment 99.9% of queries don’t have alternative query plans available (either because of forced indexes or just straightforward Primary Key read). We have various other systems and from time to time we have to do SQL work there and chase optimizer errors.

There’re multiple places where optimizer can make a choice in very basic queries, for example:

  • Which index returns less rows
  • Which index can be used for ORDER BY

A query that I was looking asked a very basic question, on a job …

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Webinar-on-demand: Learn how to add HA and DR to MySQL operating on-prem and in VMware's vCloud Air public cloud
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Learn how VMware Continuent adds HA, DR and real-time data warehouse loading to off-the-shelf MySQL operating on-prem and in VMware vCloud Air public cloud. 

We introduce vCloud Air basics, then do a deep dive into the VMware Continuent system architecture covering important issues like fail-over, zero-downtime maintenance, and load scaling. We will conclude with a demonstration of using

Showing entries 1 to 10 of 34734 10 Older Entries

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