Re: [HACKERS] GSoC 2017: Foreign Key Arrays
| От | Mark Rofail |
|---|---|
| Тема | Re: [HACKERS] GSoC 2017: Foreign Key Arrays |
| Дата | |
| Msg-id | CAJvoCutWOXV1fNu0dZOxerqXmrna+7OgFPrnXEshURuFpPZG6g@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: [HACKERS] GSoC 2017: Foreign Key Arrays (Mark Rofail <markm.rofail@gmail.com>) |
| Ответы |
Re: [HACKERS] GSoC 2017: Foreign Key Arrays
Re: [HACKERS] GSoC 2017: Foreign Key Arrays |
| Список | pgsql-hackers |
This is the query fired upon any UPDATE/DELETE for RI checks:
SELECT 1 FROM ONLY <pktable> x WHERE pkatt1 = $1 [AND ...] FOR KEY SHARE OF x
SELECT 1 FROM ONLY <pktable> x WHERE pkatt1 = $1 [AND ...] FOR KEY SHARE OF x
in the case of foreign key arrays, it's wrapped in this query:
This is where the limitation appears, the DISTINCT keyword. Since in reality, count(DISTINCT) will fall back to the default btree opclass for the array element type regardless of the opclass indicated in the access method. Thus I believe going around DISTINCT is the way to go.
This is what I came up with:
I understand there might be some syntax errors but this is just a proof of concept.
Is this the right way to go?
It's been a week and I don't think I made significant progress. Any pointers?
SELECT 1 WHERE
(SELECT count(DISTINCT y) FROM unnest($1) y)
= (SELECT count(*) FROM (<QUERY>) z)
This is what I came up with:
SELECT 1 WHERE
(SELECT COUNT(*)
FROM
(
SELECT y
FROM unnest($1) y
GROUP BY y
)
)
= (SELECT count(*) (<QUERY>) z)
I understand there might be some syntax errors but this is just a proof of concept.
Is this the right way to go?
It's been a week and I don't think I made significant progress. Any pointers?
Best Regards,
MarkRofail
MarkRofail
В списке pgsql-hackers по дате отправления: