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10 Newer Entries Showing entries 61 to 70 of 398 10 Older Entries

Displaying posts with tag: Insight for DBAs (reset)

Q&A: Putting MySQL Fabric to use
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Martin Arrieta and I gave an online presentation last week on “Putting MySQL Fabric To Use.” If you missed it, you can find a recording and the slides here, and the vagrant environment we used plus a transcript of the commands we ran here (be sure to check out the ‘sharding’ branch, as that’s what we used during the …

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Advanced MySQL Query Tuning (Aug. 6) and MySQL 5.6 Performance Schema (Aug. 13) webinars
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I will be presenting two webinars in August:

This Wednesday’s webinar on advanced MySQL query tuning …

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Examining the TokuDB MySQL storage engine file structure
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As we know different storage engines in MySQL have different file structures. Every table in MySQL 5.6 must have a .frm file in the database directory matching the table name. But where the rest of the data resides depends on the storage engine.

For MyISAM we have .MYI and .MYD files in the database directory (unless special settings are in place); for InnoDB we might have data stored in the single table space (typically ibdata1 in the database directory) or as file per table (or better said file per partition) producing a single file with …

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Prevent MySQL downtime: Set max_user_connections
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One of the common causes of downtime with MySQL is running out of connections. Have you ever seen this error? “ERROR 1040 (00000): Too many connections.” If you’re working with MySQL long enough you surely have. This is quite a nasty error as it might cause complete downtime… transient errors with successful transactions mixed with failing ones as well as only some processes stopping to run properly causing various kinds of effects if not monitored properly.

There are number of causes for running out of connections, the most common ones involving when the Web/App server is creating unexpectedly large numbers of …

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What I learned while migrating a customer MySQL installation to Amazon RDS
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Hi, I recently had the experience of assisting with a migration of a customer MySQL installation to Amazon RDS (Relational Database Service). Amazon RDS is a great platform for hosting your MySQL installation and offers the following list of pros and cons:

  • You can scale your CPU, IOPS, and storage space separately by using Amazon RDS. Otherwise you need to take downtime and upgrade physical components of a rack-mounted server.
  • Backups, software version patching, failure detection, and (some) recovery is automated …
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Monitoring MySQL flow control in Percona XtraDB Cluster 5.6
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Monitoring flow control in a Galera cluster is very important. If you do not, you will not understand why writes may sometimes be stalled. Percona XtraDB Cluster 5.6 provides 2 status variables for such monitoring: wsrep_flow_control_paused and wsrep_flow_control_paused_ns. Which one should you use?

What is flow control?

Flow control does not exist with regular MySQL replication, but only with Galera replication. It is simply the mechanism nodes are using when they are not able to keep up with …

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Reference architecture for a write-intensive MySQL deployment
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We designed Percona Cloud Tools (both hardware and software setup) to handle a very high-intensive MySQL write workload. For example, we already observe inserts of 1bln+ datapoints per day. So I wanted to share what kind of hardware we use to achieve this result.

Let me describe what we use, and later I will explain why.

Server:

  • Chassis: Supermicro SC825TQ-R740LPB 2U Rackmount Chassis
  • Motherboard: Supermicro X9DRI-F dual socket
  • CPU: Dual Intel Xeon Ivy Bridge E5-2643v2 (6x 3.5Ghz cores, 12x …
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A schema change inconsistency with Galera Cluster for MySQL
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I recently worked on a case where one node of a Galera cluster had its schema desynchronized with the other nodes. And that was although Total Order Isolation method was in effect to perform the schema changes. Let’s see what happened.

Background

For those of you who are not familiar with how Galera can perform schema changes, here is a short recap:

  • Two methods are available depending on the value of the wsrep_OSU_method setting. Both have benefits and drawbacks, it is not the main topic of this post.
  • With TOI (Total Order Isolation), a DDL statement is performed …
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Systemtap solves phantom MySQLd SIGTERM / SIGKILL issue
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The Percona Managed Services team recently faced a somewhat peculiar client issue. We’d receive pages about their MySQL service being unreachable. However, studying the logs showed nothing out of the ordinary…. for the most part it appeared to be a normal shutdown and there was nothing in anyone’s command history nor a cron task to speak of that was suspicious.

This is one of those obscure and peculiar (read: unique) issues that triggered an old memory; I’d seen this behavior before and I had just the tool to catch the culprit in the act.

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Managing shards of MySQL databases with MySQL Fabric
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This is the fourth post in our MySQL Fabric series. In case you’re joining us now, we started with an introductory post, and then discussed High Availability (HA) using MySQL Fabric here (Part 1) and here (Part 2). Today we will talk about how MySQL Fabric can help you …

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10 Newer Entries Showing entries 61 to 70 of 398 10 Older Entries

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