Horton

Re: SQL:2011 application time

Isaac Morland <isaac.morland@gmail.com>

View thread
From: Isaac Morland <isaac.morland@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Jeff Davis <pgsql@j-davis.com>, Peter Eisentraut <peter@eisentraut.org>, Paul Jungwirth <pj@illuminatedcomputing.com>, jian he <jian.universality@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2024-05-21T18:27:29Z
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 Tue, 21 May 2024 at 13:57, Robert Haas <robertmhaas@gmail.com> wrote:

What I think is less clear is what that means for temporal primary
> keys. As Paul pointed out upthread, in every other case, a temporal
> primary key is at least as unique as a regular primary key, but in
> this case, it isn't. And someone might reasonably think that a
> temporal primary key should exclude empty ranges just as all primary
> keys exclude nulls. Or they might think the opposite.
>

Fascinating. I think you're absolutely right that it's clear that two empty
intervals don't conflict. If somebody wants to claim two intervals
conflict, they need to point to at least one instant in time that is common
between them.

But a major point of a primary key, it seems to me, is that it uniquely
identifies a row. If items are identified by a time range, non-overlapping
or not, then the empty range can only identify one item (per value of
whatever other columns are in the primary key). I think for a unique key
the non-overlapping restriction has to be considered an additional
restriction on top of the usual uniqueness restriction.

I suspect in many applications there will be a non-empty constraint; for
example, it seems quite reasonable to me for a meeting booking system to
forbid empty meetings. But when they are allowed they should behave in the
mathematically appropriate way.