Horton

Re: SQL:2011 application time

Paul A Jungwirth <pj@illuminatedcomputing.com>

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From: Paul Jungwirth <pj@illuminatedcomputing.com>
To: jian he <jian.universality@gmail.com>
Cc: Isaac Morland <isaac.morland@gmail.com>, Robert Haas <robertmhaas@gmail.com>, Jeff Davis <pgsql@j-davis.com>, Peter Eisentraut <peter@eisentraut.org>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2024-07-18T18:39:09Z
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

Attachments

On 7/17/24 20:34, Paul Jungwirth wrote:
> I like this approach a lot, but I'd like to hear what some other people think?
> 
> Jian he's &&& operator is similar to what I proposed upthread, but when either operand is an empty 
> value it simply raises an error. (It should be an ereport, not an elog, and I think 
> multirange_overlaps_multirange_internal is missing the empty check, but I can clean things up when I 
> integrate it into the patch series.)

I thought of a possible problem: this operator works great if there are already rows in the table, 
but what if the *first row you insert* has an empty range? Then there is nothing to compare against, 
so the operator will never be used. Right?

Except when I test it, it still works! After running `make installcheck`, I did this:

regression=# truncate temporal_rng cascade;
NOTICE:  truncate cascades to table "temporal_fk_rng2rng"
TRUNCATE TABLE
regression=# insert into temporal_rng values ('[1,2)', 'empty');
ERROR:  range cannot be empty

My mental model must be wrong. Can anyone explain what is happening there? Is it something we can 
depend on?

So I swapped in the &&& patch, cleaned it up, and added tests. But something is wrong. After I get 
one failure from an empty, I keep getting failures, even though the table is empty:

regression=# truncate temporal_rng cascade;
NOTICE:  truncate cascades to table "temporal_fk_rng2rng"
TRUNCATE TABLE
regression=# insert into temporal_rng values ('[1,2)', '[2000-01-01,2010-01-01)'); -- ok so far
INSERT 0 1
regression=# insert into temporal_rng values ('[1,2)', 'empty'); -- should fail and does
ERROR:  range cannot be empty
regression=# insert into temporal_rng values ('[1,2)', '[2010-01-01,2020-01-01)'); -- uh oh
ERROR:  range cannot be empty
regression=# truncate temporal_rng cascade;
NOTICE:  truncate cascades to table "temporal_fk_rng2rng"
TRUNCATE TABLE
regression=# insert into temporal_rng values ('[1,2)', '[2000-01-01,2010-01-01)'); -- ok so far
INSERT 0 1
regression=# insert into temporal_rng values ('[1,2)', '[2010-01-01,2020-01-01)'); -- ok now
INSERT 0 1

It looks like the index is getting corrupted. Continuing from the above:

regression=# create extension pageinspect;
CREATE EXTENSION
regression=# select gist_page_items(get_raw_page('temporal_rng_pk', 0), 'temporal_rng_pk');
                               gist_page_items
----------------------------------------------------------------------------
  (1,"(0,1)",40,f,"(id, valid_at)=(""[1,2)"", ""[2000-01-01,2010-01-01)"")")
  (2,"(0,2)",40,f,"(id, valid_at)=(""[1,2)"", ""[2010-01-01,2020-01-01)"")")
(2 rows)

regression=# insert into temporal_rng values ('[1,2)', 'empty');
ERROR:  range cannot be empty
regression=# select gist_page_items(get_raw_page('temporal_rng_pk', 0), 'temporal_rng_pk');
                               gist_page_items
----------------------------------------------------------------------------
  (1,"(0,1)",40,f,"(id, valid_at)=(""[1,2)"", ""[2000-01-01,2010-01-01)"")")
  (2,"(0,2)",40,f,"(id, valid_at)=(""[1,2)"", ""[2010-01-01,2020-01-01)"")")
  (3,"(0,3)",32,f,"(id, valid_at)=(""[1,2)"", empty)")
(3 rows)

So maybe this is a bad place to ereport? Or is this a deeper bug with GiST? Here is where we're 
doing it:

#0  range_nonempty_overlaps_internal (typcache=0x635a7fbf67f0, r1=0x635a7fc11f20, r2=0x635a7fc11f40) 
at rangetypes.c:876
#1  0x0000635a7f06175d in range_gist_consistent_leaf_range (typcache=0x635a7fbf67f0, strategy=31, 
key=0x635a7fc11f20, query=0x635a7fc11f40)
     at rangetypes_gist.c:1076
#2  0x0000635a7f05fc9a in range_gist_consistent (fcinfo=0x7ffcd20f9f60) at rangetypes_gist.c:216
#3  0x0000635a7f12d780 in FunctionCall5Coll (flinfo=0x635a7fb44eb8, collation=0, 
arg1=140723832725648, arg2=109240340727454, arg3=31, arg4=0,
     arg5=140723832725567) at fmgr.c:1242
#4  0x0000635a7e999af6 in gistindex_keytest (scan=0x635a7fb44d50, tuple=0x7d155c0a3fd0, 
page=0x7d155c0a2000 "", offset=1, recheck_p=0x7ffcd20fa129,
     recheck_distances_p=0x7ffcd20fa12a) at gistget.c:221
#5  0x0000635a7e99a109 in gistScanPage (scan=0x635a7fb44d50, pageItem=0x7ffcd20fa1e0, 
myDistances=0x0, tbm=0x0, ntids=0x0) at gistget.c:436
#6  0x0000635a7e99a797 in gistgettuple (scan=0x635a7fb44d50, dir=ForwardScanDirection) at gistget.c:637
#7  0x0000635a7e9e4d38 in index_getnext_tid (scan=0x635a7fb44d50, direction=ForwardScanDirection) at 
indexam.c:590
#8  0x0000635a7e9e4f7d in index_getnext_slot (scan=0x635a7fb44d50, direction=ForwardScanDirection, 
slot=0x635a7fb44950) at indexam.c:682
#9  0x0000635a7ec5690b in check_exclusion_or_unique_constraint (heap=0x7d1560cea348, 
index=0x7d1560cedd98, indexInfo=0x635a7fb44c40, tupleid=0x635a7fb44580,
     values=0x7ffcd20faf00, isnull=0x7ffcd20faee0, estate=0x635a7fb434a0, newIndex=false, 
waitMode=CEOUC_WAIT, violationOK=false, conflictTid=0x0)
     at execIndexing.c:780
#10 0x0000635a7ec55c58 in ExecInsertIndexTuples (resultRelInfo=0x635a7fb43930, slot=0x635a7fb44550, 
estate=0x635a7fb434a0, update=false, noDupErr=false,
     specConflict=0x0, arbiterIndexes=0x0, onlySummarizing=false) at execIndexing.c:483
#11 0x0000635a7eca38a2 in ExecInsert (context=0x7ffcd20fb1b0, resultRelInfo=0x635a7fb43930, 
slot=0x635a7fb44550, canSetTag=true, inserted_tuple=0x0,
     insert_destrel=0x0) at nodeModifyTable.c:1145

Is there anything I can do to save this &&& idea? I've attached the patches I'm working with, 
rebased to cd85ae1114.

If ereport just won't work, then I might explore other definitions of a &&& operator. It was really 
nice to have such a clean solution.

Yours,

-- 
Paul              ~{:-)
pj@illuminatedcomputing.com