Horton

Re: cataloguing NOT NULL constraints

Alvaro Herrera <alvherre@alvh.no-ip.org>

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From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Alexander Lakhin <exclusion@gmail.com>
Cc: Dean Rasheed <dean.a.rasheed@gmail.com>, Peter Eisentraut <peter@eisentraut.org>, Robert Haas <robertmhaas@gmail.com>, pgsql-hackers@lists.postgresql.org
Date: 2023-11-08T17:53:27Z
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. Revert structural changes to not-null constraints

  2. Fix inconsistencies in error messages

  3. Disallow direct change of NO INHERIT of not-null constraints

  4. Disallow NO INHERIT not-null constraints on partitioned tables

  5. Better handle indirect constraint drops

  6. Don't try to assign smart names to constraints

  7. Fix restore of not-null constraints with inheritance

  8. ATTACH PARTITION: Don't match a PK with a UNIQUE constraint

  9. Fix propagating attnotnull in multiple inheritance

  10. Check stack depth in new recursive functions

  11. Move privilege check to the right place

  12. Update information_schema definition for not-null constraints

  13. Fix not-null constraint test

  14. Disallow changing NO INHERIT status of a not-null constraint

  15. Catalog not-null constraints

  16. parallel_schedule: add comment on event_trigger test dependency

  17. Revert "Catalog NOT NULL constraints" and fallout

  18. Adjust contrib/sepgsql regression test expected outputs.

  19. Fix table name clash in recently introduced test

  20. Catalog NOT NULL constraints

  21. Change the rules for inherited CHECK constraints to be essentially the same

On 2023-Oct-12, Alexander Lakhin wrote:

Hello,

> I've discovered that that commit added several recursive functions, and
> some of them are not protected from stack overflow.

True.  I reproduced the first two, but didn't attempt to reproduce the
third one -- patching all these to check for stack depth is cheap
protection.  I also patched ATAddCheckNNConstraint:

> (ATAddCheckNNConstraint() is protected because it calls
> AddRelationNewConstraints(), which in turn calls StoreRelCheck() ->
> CreateConstraintEntry() ->  recordDependencyOnSingleRelExpr() ->
> find_expr_references_walker() ->  expression_tree_walker() ->
> expression_tree_walker() -> check_stack_depth().)

because it seems uselessly risky to rely on depth checks that exist on
completely unrelated pieces of code, when the function visibly recurses
on itself.  Especially so since the test cases that demonstrate crashes
are so expensive to run, which means we're not going to detect it if at
some point that other stack depth check stops being called for whatever
reason.

BTW probably the tests could be made much cheaper by running the server
with a lower "ulimit -s" setting.  I didn't try.

I noticed one more crash while trying to "drop table" one of the
hierarchies your scripts create.  But it's a preexisting issue which
needs a backpatched fix, and I think Egor already reported it in the
other thread.

Thank you

-- 
Álvaro Herrera        Breisgau, Deutschland  —  https://www.EnterpriseDB.com/
"Industry suffers from the managerial dogma that for the sake of stability
and continuity, the company should be independent of the competence of
individual employees."                                      (E. Dijkstra)