Rowley: What’s new in the Postgres 16 query planner / optimizer

Sesse — Mon, 12 Feb 2024 15:26:00 +0000

An inner join is exactly equivalent to a cross-product followed by a filter on the join condition. Outer joins, however, follow different and sometimes more complex rules.

Rowley: What’s new in the Postgres 16 query planner / optimizer

LtWorf — Mon, 12 Feb 2024 07:51:40 +0000

Writing optimizations is an interesting exercise.

I did it myself (at an amateur level) with my relational algebra compiler.

I remember when i proved that a certain transformation would work for product, and I decided to apply the same to joins, since they are similar enough… they weren't similar enough and the optimization generated different results in those cases.

Of course, since only students use that software, there were no consequences.

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Rowley: What’s new in the Postgres 16 query planner / optimizer

Rowley: What’s new in the Postgres 16 query planner / optimizer