Tag - indexes

MongoDB Explain – Using PMM-QAN for MongoDB Query Analytics

MongoDB 4.0 Features Webinar

In this blog post, we will walk through PMM-Query Analytics for MongoDB. We will see how to analyze MongoDB query performance; review the initial parameters that we need to check; and find out how to compare MongoDB query performance with and without indexes with the help of EXPLAIN plan.
The Percona Monitoring and Management QAN (PMM-QAN) dashboard […]

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Four Ways MySQL Executes GROUP BY

MySQL GROUP BY

In this blog post, I’ll look into four ways MySQL executes GROUP BY. 
In my previous blog post, we learned that indexes or other means of finding data might not be the most expensive part of query execution. For example, MySQL GROUP BY could potentially be responsible for 90% or more of the query execution time. 
The […]

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MySQL Query Performance: Not Just Indexes

Running MySQL in Kubernetes

In this blog post, I’ll look at whether optimizing indexing is always the key to improving MySQL query performance (spoiler, it isn’t).
As we look at MySQL query performance, our first concern is often whether a query is using the right indexes to retrieve the data. This is based on the assumption that finding the data is […]

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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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Webinar Wednesday July 12, 2017: MongoDB Index Types – How, When and Where Should They Be Used?

MongoDB Index Types

Join Percona’s Senior Technical Services Engineer, Adamo Tonete as he presents MongoDB Index Types: How, When and Where Should They Be Used? on Wednesday, July 12, 2017 at 11:00 am PDT / 2:00 pm EDT (UTC-7).
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MongoDB has 12 index types. Do you know how each works, or when you should use each of […]

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MongoDB Indexing Types: How, When and Where Should They Be Used?

MongoDB Index Types

In this blog post, we will talk about MongoDB indexing, and the different types of indexes that are available in MongoDB.
Note: We are hosting a webinar on July 12, 2017, where I will talk about MongoDB indexes and how to choose a good indexing plan.
MongoDB is a NoSQL database that is document-oriented. NoSQL databases […]

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Webinar Wednesday July 5, 2017: Indexes – What You Need to Know to Get the Most Out of Them

Indexes

Join Percona’s Senior Architect, Matthew Boehm, as he presents Indexes – What You Need to Know to Get the Most Out of Them on Wednesday, July 5, 2017 at 8:00 am PDT / 11:00 am EDT (UTC-7).
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Proper indexing is key to database performance. Find out how MySQL uses indexes for query execution, and then how […]

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Basic Housekeeping for MySQL Indexes

MySQL Indexes

In this blog post, we’ll look at some of the basic housekeeping steps for MySQL indexes.
We all know that indexes can be the difference between a high-performance database and a bad/slow/painful query ride. It’s a critical part that needs deserves some housekeeping once in a while. So, what should you check? In no particular order, […]

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Find unused indexes on MongoDB and TokuMX

Finding and removing unused indexes is a pretty common technique to improve overall performance of relational databases. Less indexes means faster insert and updates but also less disk space used. The usual way to do it is to log all queries’ execution plans and then get a list of those indexes that are not […]

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Speed up MySQL Queries GROUP BY with subselects

Speed up queries on MySQL

We usually try to avoid subselects because sometimes they force the use of a temporary table and limits the use of indexes. But, when is good to use a subselect?
This example was tested over table a (1310723 rows), b, c and d ( 5 rows each) and with MySQL version 5.5 and 5.6.
Let’s suppose […]

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