Tag - explain

MongoDB: Investigate Queries with explain() and Index Usage (part 2)

MongoDB explain() method optimization tool

This is the second part of a two parts series. In MongoDB: index usage and MongoDB explain() we introduced the main index types supported by MongoDB, and how to create and use them. In this second article, we are going to see some examples on how to use explain() method to investigate queries. Do […]

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Webinar: How to Analyze and Tune MySQL Queries for Better Performance

database query tuning

Please join Percona’s MySQL Database Administrator, Brad Mickel as he presents How to Analyze and Tune MySQL Queries for Better Performance on Thursday, June 21st, 2018, at 10:00 AM PDT (UTC-7) / 1:00 PM EDT (UTC-4).
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Query performance is essential in making any application successful. In order to finely tune your queries you first […]

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Webinar Thursday, October 19, 2017: What You Need to Get the Most Out of Indexes – Part 2

Indexes

Join Percona’s Senior Architect, Matthew Boehm, as he presents What You Need to Get the Most Out of Indexes – Part 2 webinar on Thursday, October 19, 2017, at 11:00 am PDT / 2:00 pm EDT (UTC-7).
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Proper indexing is key to database performance. Finely tune your query writing and database performance with tips […]

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Introduction to Troubleshooting Performance – Troubleshooting Slow Queries webinar: Q & A

InnoDB Troubleshooting

In this blog, I will provide answers to the Q & A for the Troubleshooting Slow Queries webinar.
First, I want to thank you for attending the April 28 webinar. The recording and slides for the webinar are available here. Below is the list of your questions that I wasn’t able to answer during the webinar, with […]

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EXPLAIN FORMAT=JSON: nested_loop makes JOIN hierarchy transparent

EXPLAIN FORMAT=JSON

Once again it’s time for another EXPLAIN FORMAT=JSON is cool! post. This post will discuss how EXPLAIN FORMAT=JSON allows the nested_loop command to make the JOIN operation hierarchy transparent.
The regular
EXPLAIN  command lists each table that participates in a 
JOIN  operation on a single row. This works perfectly for simple queries:

MySQL

mysql> explain select * from […]

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