Most people who have worked with a Windows PC, especially in the past where SSD disks were not that common, are aware of a utility tool called Disk Defragmenter.

Microsoft included Disk Defragmenter with all their OS distribution. Now, you might wonder why we mention a Windows OS utility tool in a guide about Amazon Redshift, but there’s a similar process related to Amazon Redshift. That process is Vacuuming, and it also happens to be quite important for the health and maintenance of our Redshift cluster.
The Vacuuming process is quite important for the health and maintenance of your AWS Redshift cluster.
The purpose of the Disk Defragmenter was to rearrange the files on the disk to increase access speed. The Vacuuming process of tables on an Amazon Redshift cluster is of course not about rearranging files, but instead about reclaiming freed space under some specific conditions.
However, as with Disk Defragmenter, the Vacuum command process is an important process that also affects the performance of our queries, among others.
Vacuum is an important process which also affects the performance of our queries, among others.