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The section on parallel joins is a bit out of date. Shameless plug: I've written and spoken about this subject extensively, if you are looking for more inform
by macdice 7y ago
The section on parallel joins is a bit out of date. Shameless plug: I've written and spoken about this subject extensively, if you are looking for more information, with further links and pointers to other blogs and academic papers.
Parallelism in PostgreSQL in general:
https://speakerdeck.com/macdice/parallelism-in-postgresql-11 https://speakerdeck.com/macdice/parallelism-in-postgresql-11
Deeper dives on hash joins:
https://write-skew.blogspot.com/2018/01/parallel-hash-for-postgresql.html https://write-skew.blogspot.com/2018/01/parallel-hash-for-po...
https://speakerdeck.com/macdice/hash-joins-past-present-and-future https://speakerdeck.com/macdice/hash-joins-past-present-and-...
- ibrar74 7y agoIt is not outdated, it has less information. The parallel joins is a bigger topic itself. In this blog, I want to give a brief introduction about parallelism in PostgreSQL. I will definitely read what you suggested. But keep in touch I will post more blogs for each sub-topic to cover it all.
- macdice 7y agoCool. I was just reacting to the fact that you highlighted merge joins in parallel queries with a partial plan on the outer side only, which was a new feature back in 2017 when 10 came out (and was already supported for hash joins and nested loops since 9.6), without mentioning that in 2018 when 11 came out we got parallel hash joins that can use a partial plan on both sides of the join.