The test that checks the expected plan for this self-join test has been known to have failed in the past due to badly timed VACUUMs causing small variations in row estimates on one of the tables, resulting in a swapped join order. Currently, failures have only been seen in v14, and seemingly due to74388a1acand4496020e6the failures have not been seen in more recent versions. Here we shrink down the number of matching rows on one side of the join to make the alternative join order's costs more expensive relative to the cheapest join order. Previously the alternative order had the same cost. We do this in all supported versions to reduce the chances of future changes reintroducing stability issues with these queries. Reported-by: Alexander Lakhin <exclusion@gmail.com> Author: David Rowley <dgrowleyml@gmail.com> Discussion: https://postgr.es/m/f5d1f4c2-6224-4797-be17-c86e77f96c9c@gmail.com Backpatch-through: 14
PostgreSQL Database Management System
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PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
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