Fix "before delete" trigger on Scheduling Specification Conditions #1631
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If a "before" trigger returns `NULL`, the operation is cancelled, as per the Postgres Documentation (https://www.postgresql.org/docs/16/trigger-definition.html).
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mattdailis
approved these changes
Jan 29, 2025
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Description
If a "before" trigger returns
NULL, the operation is cancelled, as per the Postgres Documentation.Since
newis not defined in adeletetrigger, the trigger would always returnnull, cancelling the deletion. This made it impossible to remove scheduling conditions from a plan's specification.Verification
Bryan tested the new code and proved that it fixed the bug.
Additionally, I searched for all instances of "before delete" triggers, since this is not an issue with "after" triggers (from the docs "The return value is ignored for row-level triggers fired after an operation, and so they can return NULL."). The regex search I used was
before .*delete.Future work
Nowhere near the scope of this ticket, but the fact that it took just over a year for this bug to be observed gives the impression that Scheduling Conditions aren't used that often. Given the current work to increase the power of goals and constraints, I think they may end up obsoleting conditions entirely.