Re: [HACKERS] GSoC 2017: Foreign Key Arrays - Mailing list pgsql-hackers

From Alexander Korotkov
Subject Re: [HACKERS] GSoC 2017: Foreign Key Arrays
Date
Msg-id CAPpHfdvxzbRBL2zytnkd1RWuY8-eig2mE4=KmCbOHGaOh2hV9g@mail.gmail.com
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In response to Re: [HACKERS] GSoC 2017: Foreign Key Arrays  (Mark Rofail <markm.rofail@gmail.com>)
Responses Re: [HACKERS] GSoC 2017: Foreign Key Arrays
Re: [HACKERS] GSoC 2017: Foreign Key Arrays
List pgsql-hackers
On Thu, Jul 27, 2017 at 3:07 PM, Mark Rofail <markm.rofail@gmail.com> wrote:
On Thu, Jul 27, 2017 at 12:54 PM, Alexander Korotkov <aekorotkov@gmail.com> wrote:
How many rows of FK table were referencing the PK table row you're updating/deleting.
I wonder how may RI trigger work so fast if it has to do some job besides index search with no results?
The problem here is that the only to option for the foreign key arrays are NO ACTION and RESTRICT which don't allow me to update/delete a refrenced row in the PK Table. the EXPLAIN ANALYZE only tells me that this violates the FK constraint.

So we have two options. Either implement CASCADE or if there's a configration for EXPLAIN to show costs even if it violates the FK constraints.

Oh, ok.  I missed that.
Could you remind me why don't we have DELETE CASCADE?  I understand that UPDATE CASCADE is problematic because it's unclear which way should we delete elements from array.  But what about DELETE CASCADE?

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company 

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