FK Constraint sort order with pg_dump
От | Christian Barthel |
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Тема | FK Constraint sort order with pg_dump |
Дата | |
Msg-id | 87h73a4bu3.fsf@online.de обсуждение исходный текст |
Ответы |
Re: FK Constraint sort order with pg_dump
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Список | pgsql-general |
Hello, The sorting order of FK constraints with the same name is based on the OID (because it lands in the “Usually shouldn’t get here” OID comparison block at [1]). Wouldn’t it be better if the order of those constraints were based on the table name? Details: The above schema is identical except in the order how the constraints were added (the constraint name is the same on those two tables): --8<---------------cut here---------------start------------->8--- -- --- Schema Version 1: CREATE TABLE a (id int unique); CREATE TABLE b (id int); ALTER TABLE b ADD CONSTRAINT x_fkey FOREIGN KEY (id) REFERENCES a(id); CREATE TABLE c (id int); ALTER TABLE c ADD CONSTRAINT x_fkey FOREIGN KEY (id) REFERENCES a(id); -- --- Schema Version 2: CREATE TABLE a (id int unique); CREATE TABLE c (id int); ALTER TABLE c ADD CONSTRAINT x_fkey FOREIGN KEY (id) REFERENCES a(id); CREATE TABLE b (id int); ALTER TABLE b ADD CONSTRAINT x_fkey FOREIGN KEY (id) REFERENCES a(id); --8<---------------cut here---------------end--------------->8--- Doing a pg_dump on Version 1 and Version 2 leads to two different dumps despite being the same schema: (*) --8<---------------cut here---------------start------------->8--- --- version1 2022-07-21 19:16:31.369010843 +0200 +++ version2 2022-07-21 19:16:26.688976178 +0200 @@ -86,18 +86,18 @@ -- --- Name: b x_fkey; Type: FK CONSTRAINT; Schema: public; Owner: bch +-- Name: c x_fkey; Type: FK CONSTRAINT; Schema: public; Owner: bch -- -ALTER TABLE ONLY public.b +ALTER TABLE ONLY public.c ADD CONSTRAINT x_fkey FOREIGN KEY (id) REFERENCES public.a(id); -- --- Name: c x_fkey; Type: FK CONSTRAINT; Schema: public; Owner: bch +-- Name: b x_fkey; Type: FK CONSTRAINT; Schema: public; Owner: bch -- -ALTER TABLE ONLY public.c +ALTER TABLE ONLY public.b ADD CONSTRAINT x_fkey FOREIGN KEY (id) REFERENCES public.a(id); --8<---------------cut here---------------end--------------->8--- Attached is a patch file that adds a string comparison function call to sort FK constraints (based on the table if it exists). Any thoughts on that? [1] https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/bin/pg_dump/pg_dump_sort.c;h=80641cd79a2e6ce0a10bd55218b10d22ac369ed5;hb=7c850320d8cfa5503ecec61c2559661b924f7595#l212 (*) Tested on 14.4 -- Christian Barthel
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