Enabling Real-Time Analytics With Database In-Memory

  • May 25, 2018

Focus on Hash Joins

Andy Rivenes
Product Manager

I've posted three new videos of the demonstrations that Maria Colgan (@SQLMaria) and I (@TheInMemoryGuy) did in our Ask TOM Office Hours session focusing on hash joins. This is a follow up to the posts that we did on Hash Joins and Join Groups and goes into more detail with actual demonstrations in SQL*Plus.

The videos are available on our Database In-Memory YouTube channel and are listed in our DBIM demos playlist. There are three videos and in them we run queries to show how Database In-Memory uses hash joins with Bloom filters to provide up to a 10x performance improvement over a traditional row-store based hash join. We also cover how Database In-Memory can leverage multiple Bloom filters to turn a multi-table join into a scan and filter operation, and then we explore how the 12.2 feature Join Groups further enhances join performance.

The full Ask TOM session is available here if you want to review all of the background on hash joins and even more detail on how they work with Database In-Memory. We encourage you to subscribe so that you will be notified of our future sessions as well.


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