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Comments for Inside PostgreSQL -- Multi-Batch Hash Join Improvements #122

Open phinjensen opened 7 years ago

phinjensen commented 7 years ago

Comments for https://www.endpointdev.com/blog/2009/03/inside-postgresql-multi-batch-hash-join/ By Josh Tolley

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phinjensen commented 7 years ago 
original author: Ethan Rowe
date: 2009-03-28T23:31:00-04:00

Thanks for the interesting write-up, and for helping out with patch.

When you say that it leads to "noticeable" performance improvements in common cases, what kind of gains are we talking about?

Good stuff. Thanks again.

phinjensen commented 7 years ago 
original author: Joshua Tolley
date: 2009-04-01T08:52:00-04:00

It varied a lot, being dependent not only on the database skew but also on how well PostgreSQL could characterize the skew in its internal statistics. Some of my fairly haphazard testing, as I recall, showed speedups under some conditions of ~20%.