Horton

Re: SQL:2011 application time

Peter Eisentraut <peter@eisentraut.org>

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From: Peter Eisentraut <peter@eisentraut.org>
To: Paul Jungwirth <pj@illuminatedcomputing.com>
Cc: jian he <jian.universality@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, vignesh C <vignesh21@gmail.com>
Date: 2025-03-03T10:05:22Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Rename gist stratnum support function

  2. Remove support for temporal RESTRICT foreign keys

  3. Cache NO ACTION foreign keys separately from RESTRICT foreign keys

  4. Fix NO ACTION temporal foreign keys when the referenced endpoints change

  5. Improve whitespace in without_overlaps test

  6. Tests for logical replication with temporal keys

  7. Support for GiST in get_equal_strategy_number()

  8. Make the conditions in IsIndexUsableForReplicaIdentityFull() more explicit

  9. Replace get_equal_strategy_number_for_am() by get_equal_strategy_number()

  10. Improve internal logical replication error for missing equality strategy

  11. Simplify IsIndexUsableForReplicaIdentityFull()

  12. Fix ALTER TABLE / REPLICA IDENTITY for temporal tables

  13. doc: Update pg_constraint.conexclop docs for WITHOUT OVERLAPS

  14. doc: Add PERIOD to ALTER TABLE reference docs

  15. doc: Add WITHOUT OVERLAPS to ALTER TABLE reference docs

  16. Add temporal FOREIGN KEY contraints

  17. Add temporal PRIMARY KEY and UNIQUE constraints

  18. Add stratnum GiST support function

  19. Avoid crashing when a JIT-inlined backend function throws an error.

  20. Revert temporal primary keys and foreign keys

  21. Fix ON CONFLICT DO NOTHING/UPDATE for temporal indexes

  22. Add test for REPLICA IDENTITY with a temporal key

  23. Use half-open interval notation in without_overlaps tests

  24. Use daterange and YMD in without_overlaps tests instead of tsrange.

  25. Rename pg_constraint.conwithoutoverlaps to conperiod

  26. Fix comment on gist_stratnum_btree

  27. Add missing TAP test name

  28. Improve error handling of HMAC computations

  29. Rename functions to avoid future conflicts

On 26.02.25 06:15, Paul Jungwirth wrote:
> I agree with that last principle: it shouldn't matter how the primary 
> keys are split up. But it seems to me that "matches" in the standard 
> should include the period. It does for NO ACTION, so why not RESTRICT? 
> That's why your example of expanding the referenced range succeeds. None 
> of the referenced moments were changed, so there are no referencing 
> moments to match.
> 
>  > I'm not sure what other behavior of RESTRICT there might be that is 
> internally consistent and is
>  > meaningfully different from NO ACTION.
> 
> The difference between RESTRICT and NO ACTION for temporal foreign keys 
> is the same as the difference for ordinary foreign keys: we perform the 
> check prior to applying any "action" or allowing any other commands to 
> provide substitutes for the lost references. There are tests in sql/ 
> without_overlaps.sql showing how their behavior differs.
> 
> Also you haven't yet explained why anyone would *want* to use RESTRICT 
> as you've described it, since the temporal part of the key is just 
> ignored, and they could just define a non-temporal foreign key instead. 
> Or to be precise, it fails *more* than a non-temporal foreign key, 
> because changing the period can violate the constraint, even though we 
> ignore the period when looking for matches.

This is not what I'm aiming for.  (Maybe my patches were wrong about that.)

In the theory of the SQL standard, executing referential actions and 
checking the foreign-key constraint are two separate steps.  So it kind 
of goes like this:

1. run command
2. run any referential actions
3. check that foreign key is still satisfied

This is why the default referential action is called "NO ACTION": It 
just skips the step 2.  But it still does step 3.

This means that under RESTRICT and with my interpretation, the check for 
a RESTRICT violation in step 2 can "ignore" the period part, but the 
step 3 still has to observe the period part.

In the implementation, these steps are mostly combined into one trigger 
function, so it might be a bit tricky to untangle them.

> But since we don't agree on the behavior, it seems best to me to wait to 
> implement RESTRICT. Not much is lost, since NO ACTION is so similar. We 
> can wait for the SQL committee to clarify things, or see what another 
> RDBMS vendor does.

I'm fine with that.