The Ultimate Guide to High Availability with MariaDB

LooseScan strategy

You are viewing an old version of this article. View the current version here.

LooseScan is an execution strategy for Semi-join subqueries.

The idea

LooseScan strategy eliminates duplicates by using an ordered index. When one scans an index, they get records with the same key value together.

Let's look at a query that searches for countries that have satellites:

select * from Country  
where 
  Country.code in (select country_code from Satellite)

Comments

Comments loading...
Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.