Adds support for deferrable exclude constraints in PostgreSQL. #47655
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yahonda
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Mar 14, 2023
activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
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By default, exclude constraints in PostgreSQL are checked after each statement. This works for most use cases, but becomes a major limitation when replacing records with overlapping ranges by using multiple statements. ```ruby exclusion_constraint :users, "daterange(valid_from, valid_to) WITH &&", deferrable: :immediate ``` Passing `deferrable: :immediate` checks constraint after each statement, but allows manually deferring the check using `SET CONSTRAINTS ALL DEFERRED` within a transaction. This will cause the excludes to be checked after the transaction. It's also possible to change the default behavior from an immediate check (after the statement), to a deferred check (after the transaction): ```ruby exclusion_constraint :users, "daterange(valid_from, valid_to) WITH &&", deferrable: :deferred ``` *Hiroyuki Ishii*
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@yahonda I have fixed the PR based on your review comments. 😄 |
yahonda
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Mar 14, 2023
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Motivation / Background
By default, exclude constraints in PostgreSQL are checked after each row. This works for most use cases, but becomes a major limitation when replacing records with overlapping ranges by using multiple statements.
Passing
deferrable: :immediatechecks constraint after each statement, but allows manually deferring the check usingSET CONSTRAINTS ALL DEFERREDwithin a transaction. This will cause the excludes to be checked after the transaction.It's also possible to change the default behavior from an immediate check (after the statement), to a deferred check (after the transaction):
Detail
This is follow up to #40224
Additional information
It is with reference to this comment that the
deferrableoption accepts only:immediateand:deferred.Checklist
Before submitting the PR make sure the following are checked:
[Fix #issue-number]