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Displaying posts with tag: Insight for DBAs (reset)
Replay the Execution of MySQL With RR (Record and Replay)

Chasing bugs can be a tedious task, and multi-threaded software doesn’t make it any easier. Threads will be scheduled at different times, instructions will not have deterministic results, and in order for one to reproduce a particular issue, it might require the exact same threads, doing the exact same work, at the exact same time. As you can imagine, this is not straightforward.

Let’s say your database is crashing or even having a transient stall.  By the time you get to it, the crash has happened and you are stuck restoring service quickly and doing after-the-fact forensics.  Wouldn’t it be nice to replay the work from right before or during the crash and see exactly what was happening?

Record and Replay is a technique where we record the execution of a program allowing it to be replayed over and over producing the same result. Engineers at …

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Percona XtraBackup Point-In-Time Recovery for the Single Database

Recovering to a particular time in the past is called Point-In-Time Recovery (PITR). With PITR you can rollback unwanted DELETE without WHERE clause or any other harmful command.

PITR with Percona XtraBackup is pretty straightforward and perfectly described in the user manual. You need to restore the data from the backup, then apply all binary logs created or updated after the backup was taken, but skip harmful event(s).

However, if your data set is large you may want to recover only the affected database or table. This is possible but you need to be smart when filtering events from the binary log. In this post, I will show how to perform such a partial recovery using Percona XtraBackup, …

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Upgrading to MySQL 8: Embrace the Challenge

Nobody likes change, especially when that change may be challenging.  When faced with a technical challenge, I try to remember this comment from Theodore Roosevelt: “Nothing in the world is worth having or worth doing unless it means effort, pain, difficulty.”  While this is a bit of an exaggeration, in this case, the main concept is still valid.  We shouldn’t shy away from an upgrade path because it may be difficult.

MySQL 8.0 is maturing and stabilizing.  There are new features (too many to list here) and performance improvements.  More and more organizations are upgrading to MySQL 8 and running it in production, which expedites the stabilization.  While there is still some significant runway on 5.7 and it is definitely stable (EOL slated for October 2023), organizations need to be preparing to make the jump if they haven’t already. 

What Changed?

So …

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Easily Validate Configuration Settings in MySQL 8

In past versions of MySQL, there was often an ‘upgrade dance’ that had to be performed in starting up a newly upgraded MySQL instance with the previous version configuration file. In some cases a few deprecated options might no longer be supported in the newer server version, triggering an error and a subsequent shutdown moments after starting. The same thing can happen even outside of upgrade scenarios if a configuration change was made with a mistake or typo in the variable name or value.

As of MySQL 8.0.16 and later, there is now a ‘validate-config’ option to quickly test and validate server configuration options without having to start the server. Once used, if no issues are found with the configuration file, the server will exit with an exit code of zero (0). If a problem is found, the server will exit with an error code of one (1) for the first occurrence of anything that is determined to be invalid.

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Webinar April 14: Optimize and Troubleshoot MySQL Using Percona Monitoring and Management

Optimizing MySQL performance and troubleshooting MySQL problems are two of the most critical and challenging tasks for MySQL DBAs. The databases powering applications need to be able to handle changing traffic workloads while remaining responsive and stable in order to deliver an excellent user experience. Further, DBAs are also expected to find cost-efficient means of solving these issues.

In this webinar, we will demonstrate the advanced options of Percona Monitoring and Management V.2 that enable you to solve these challenges, which are built on free and open-source software. We will look at specific, common MySQL problems and review them.

Please join Peter Zaitsev on Wednesday, April 14th, 2021, at 11 am EDT for his webinar Optimize and Troubleshoot MySQL using Percona Monitoring and Management (PMM).

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MySQL 101: Using super_read_only

As many of you may remember, Percona added the super_read_only feature way back in Percona Server for MySQL 5.6.21, based on work done by WebScaleSQL. This feature eventually found its way into the Community branch of MySQL starting with 5.7.8, and it works the same in both cases. While this is now old news, over the last year I’ve had a couple of inquiries from clients around super_read_only usage in MySQL, and how it works in practice. While the usage of super_read_only is not complex, there is a small caveat that occasionally leads to some confusion around its use. As such, I thought it may be a good idea to write a quick blog post explaining this feature a bit more, and expanding on how it interacts with read_only.

What is super_read_only?

For those unfamiliar, what …

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Overview of MySQL Alternative Storage Engines

For MySQL, MyISAM and InnoDB storage engines are very popular. Currently, we are mostly using InnoDB engines for high reliability and high performance. Apart from those engines, we also have some other alternative engines and they have some nice features in them. In this blog, I am going to explain some of those engines, which I have listed below. 

  • FEDERATED Storage Engine
  • Merge or MRG_MyISAM Engine
  • Blackhole Engine
  • CSV Engine

FEDERATED Storage Engine Overview:

  • FEDERATED Storage Engine allows you to access the data remotely without replication and cluster technologies. 
  • Using the FEDERATED tables, you can scale your server load. Queries for the given table will be sent over the network to another MySQL instance. In this case, to scale the DB, you can use many MySQL instances without changing the application code.
  • FEDERATED tables …
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Importing an Encrypted InnoDB Tablespace into MySQL

Transportable tablespaces were introduced in MySQL 5.6. Using this feature, we can directly copy a tablespace to another server and populate the table with data. This is a very useful feature for large tables. The transportable tablespace mechanism is faster than any other method for exporting and importing tables because the files containing the data just need to be copied to the target location using traditional Linux commands (cp, scp, rsync). Our post MySQL 5.6 Transportable Tablespaces best practices covers the best practices about transportable tablespaces. The feature also supports encrypted tablespaces, and in this article, I am going to explain how to use this feature with them.

Requirements

Below I am sharing my current setup and the requirements.

  • I have two servers – s1 and s2. …
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Is a Session Analyzer a Good Tool to Simulate Real Traffic?

Starting a long time ago, we wanted to reproduce workload in a non-production environment, and there were different attempts to achieve that goal (Query Playback is just one of them). But there is another point of view, where you need to write your own workload to do so.

Both Have Pros and Cons

Reproduce Workload:

Pros:

  • Simple to implement
  • Ready to go

Cons:

  • Need to rebuild the environment each time

Custom Scripts:

Pros:

  • Possible to have a more realistic workload
  • You can reuse the environment
  • You can use Sysbench that allows you to change …
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How to Build Percona Server for MySQL From Sources

Lately, the number of questions about how to build Percona software has been increased. More and more people try to add their own patches, add some modifications, and build software by themselves. But this raises the question of how to do this in the same way as Percona does, as sometimes the compiler flag can make a drastic impact on the final binary.

First of all, let’s talk about the stages of compiling software.

I would say that at the beginning you need to prepare the build environment, install all the needed dependencies, and so on. For each version, the dependency list would be different. How do you get the correct dependency list? You can get all build requirements from the spec file (on rpm-based systems) or from the control file( on deb-based systems).

The next stage is to get the source code of Percona …

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