Horton

Re: cataloguing NOT NULL constraints

Alexander Lakhin <exclusion@gmail.com>

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From: Alexander Lakhin <exclusion@gmail.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>, Dean Rasheed <dean.a.rasheed@gmail.com>, Peter Eisentraut <peter@eisentraut.org>
Cc: Robert Haas <robertmhaas@gmail.com>, pgsql-hackers@lists.postgresql.org
Date: 2023-10-12T10:00:01Z
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

Hi Alvaro,

25.08.2023 14:38, Alvaro Herrera wrote:
> I have now pushed this again.  Hopefully it'll stick this time.

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

Namely, with "max_locks_per_transaction = 600" and default ulimit -s (8192),
I observe server crashes with the following scripts:
# ATExecSetNotNull()
(n=40000; printf "create table t0 (a int, b int);";
for ((i=1;i<=$n;i++)); do printf "create table t$i() inherits(t$(( $i - 1 ))); "; done;
printf "alter table t0 alter b set not null;" ) | psql >psql.log

# dropconstraint_internal()
(n=20000; printf "create table t0 (a int, b int not null);";
for ((i=1;i<=$n;i++)); do printf "create table t$i() inherits(t$(( $i - 1 ))); "; done;
printf "alter table t0 alter b drop not null;" ) | psql >psql.log

# set_attnotnull()
(n=110000; printf "create table tp (a int, b int, primary key(a, b)) partition by range (a); create table tp0 (a int 
primary key, b int) partition by range (a);";
for ((i=1;i<=$n;i++)); do printf "create table tp$i partition of tp$(( $i - 1 )) for values from ($i) to (1000000) 
partition by range (a);"; done;
printf "alter table tp attach partition tp0 for values from (0) to (1000000);") | psql >psql.log # this takes half an 
hour on my machine

May be you would find appropriate to add check_stack_depth() to these
functions.

(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().)

(There were patches prepared for similar cases [1], but they don't cover new
functions, of course, and I'm not sure how to handle all such instances.)

[1] https://commitfest.postgresql.org/45/4239/

Best regards,
Alexander