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Showing entries 1 to 10 of 418 10 Older Entries

Displaying posts with tag: Insight for DBAs (reset)

Multi-source replication in MySQL 5.7 vs Tungsten Replicator
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MySQL 5.7 comes with a new set of features and multi-source replication is one of them. In few words this means that one slave can replicate from different masters simultaneously.

During the last couple of months I’ve been playing a lot with this trying to analyze its potential in a real case that I’ve been facing while working with a customer.

This was motivated because my customer is already using multi-sourced slaves with Tungsten Replicator and I wanted to do a side-by-side comparison between Tungsten Replicator and Multi-source Replication in MySQL 5.7

Consider the following scenario:

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MySQL QA Episode 9: Reducing Testcases for Experts: multi-threaded reducer.sh
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Welcome to MySQL QA Episode 9. This episode will go more in-depth into reducer.sh: Reducing Testcases for Experts: multi-threaded reducer.sh

We will explore how to use reducer.sh to do true multi-threaded testcase reduction – a world’s first.

Topics:

  1. Expert configurable variables & their default reducer.sh settings
    1. PQUERY_MULTI
    2. PQUERY_MULTI_THREADS
    3. PQUERY_MULTI_CLIENT_THREADS
    4. PQUERY_MULTI_QUERIES
    5. PQUERY_REVERSE_NOSHUFFLE_OPT

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The Q&A: Creating best-in-class backup solutions for your MySQL environment
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Thank you for attending my July 15 webinar, “Creating Best in Class Backup solutions for your MySQL environment.” Due to the amount of content we discussed and some minor technical difficulties faced near the end of webinar we have decided to cover the final two slides of the presentation along with the questions asked by attendees during the webinar via this blog post.

The …

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MySQL QA Episode 8: Reducing Testcases for Engineers: tuning reducer.sh
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Welcome to MySQL QA Episode 8: Reducing Testcases for Engineers: tuning reducer.sh

  1. Advanced configurable variables & their default/vanilla reducer.sh settings
    1. FORCE_SKIPV
    2. FORCE_SPORADIC
    3. TIMEOUT_COMMAND & TIMEOUT_CHECK
    4. MULTI_THREADS
    5. MULTI_THREADS_INCREASE
    6. QUERYTIMEOUT
    7. STAGE1_LINES
    8. SKIPSTAGE
    9. FORCE_KILL
  2. Some examples
    1. FORCE_SKIPV/FORCE_SPORADIC
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MySQL QA Episode 7: Reducing Testcases for Beginners – single-threaded reducer.sh!
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Welcome to MySQL QA Episode #7 – Reducing Testcases for Beginners: single-threaded reducer.sh!

In this episode we’ll learn how to use reducer.sh. Topics discussed;

  1. reducer.sh introduction/concepts
  2. Basic configurable variables & their default reducer.sh settings
    1. INPUTFILE options
    2. MODE=x
    3. TEXT=”text”
    4. WORKDIR_LOCATION & WORKDIR_M3_DIRECTORY
    5. MYEXTRA
    6. MYBASE
    7. PQUERY_MOD & PQUERY_LOC
    8. MODE5_COUNTTEXT, …
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How to create a rock-solid MySQL database backup & recovery strategy
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Have you ever wondered what could happen if your MySQL database goes down?

Although it’s evident such a crash will cause downtime – and surely some business impact in terms of revenue – can you do something to reduce this impact?

The simple answer is “yes” by doing regular backups (of course) but are you 100% sure that your current backup strategy will really come through when an outage occurs? And how much precious time will pass (and how much revenue will be lost) before you get your business back online?

I usually think of backups as the step after HA fails. Let’s say we’re in …

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How to obtain the MySQL version from an FRM file
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I recently helped a customer figure out why a minor version MySQL upgrade was indicating that some tables needed to be rebuilt. The mysql_upgrade program should be run for every upgrade, no matter how big or small the version difference is, but when only the minor version changes, I would normally not expect it to require tables to be rebuilt.

Turns out some of their tables were still marked with an older MySQL version, which could mean a few things… most likely that something went wrong with a previous upgrade, or that the tables were copied from a server with an older version.

In cases like this, did you know there is a fast, safe and …

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MySQL QA Episode 3: How to use the debugging tool GDB
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Welcome to MySQL QA Episode 3: “Debugging: GDB, Backtraces, Frames and Library Dependencies”

In this episode you’ll learn how to use debugging tool GDB. The following debugging topics are covered:

1. GDB Introduction
2. Backtrace, Stack trace
3. Frames
4. Commands & Logging
5. Variables
6. Library dependencies
7. c++filt
8. Handy references
– GDB Cheat sheet (page #2): https://goo.gl/rrmB9i
– From Crash to testcase:  …








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Getting EXPLAIN information from already running queries in MySQL 5.7
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When a new version of MySQL is about to be released we read a lot of blog posts about the performance and scalability improvements. That’s good but sometimes we miss some small features that can help us a lot in our day-to-day tasks. One good example is the blog post that Aurimas wrote about a new small feature in MySQL 5.6 that I didn’t know about until I read it: the Automatic InnoDB transaction log file size change. How cool is that?

I plan to write a series of blog posts that will show some of those small …

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Optimizing Percona XtraDB Cluster for write hotspots
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Some applications have a heavy write workload on a few records – for instance when incrementing a global counter: this is called a write hotspot. Because you cannot update the same row simultaneously from multiple threads, this can lead to performance degradation. When using Percona XtraDB Cluster (PXC), some users try to solve this specific issue by writing on multiple nodes at the same time. Good idea or bad idea? Read on!

Simultaneous writes on a standalone InnoDB server

Say you have these 3 transactions being run …

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Showing entries 1 to 10 of 418 10 Older Entries

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