Horton

Re: Schema variables - new implementation for Postgres 15

Pavel Stehule <pavel.stehule@gmail.com>

View thread
From: Pavel Stehule <pavel.stehule@gmail.com>
To: Sergey Shinderuk <s.shinderuk@postgrespro.ru>
Cc: Tomas Vondra <tomas.vondra@enterprisedb.com>, Julien Rouhaud <rjuju123@gmail.com>, dean.a.rasheed@gmail.com, er@xs4all.nl, joel@compiler.org, pgsql-hackers@lists.postgresql.org
Date: 2022-11-15T05:00:44Z
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. Allow underscores in integer and numeric constants.

  2. Remove special outfuncs/readfuncs handling of RangeVar.catalogname.

  3. Remove extra space from dumped ALTER DEFAULT PRIVILEGES.

  4. Create FKs properly when attaching table as partition

  5. psql: improve tab-complete's handling of variant SQL names.

po 14. 11. 2022 v 8:00 odesílatel Sergey Shinderuk <
s.shinderuk@postgrespro.ru> napsal:

> On 13.11.2022 20:59, Pavel Stehule wrote:
> > fresh rebase
>
> Hello,
>
> Sorry, I haven't been following this thread, but I'd like to report a
> memory management bug. I couldn't apply the latest patches, so I tested
> with v20221104-1-* patches applied atop of commit b0284bfb1db.
>
>
> postgres=# create variable s text default 'abc';
>
> create function f() returns text as $$
> begin
>          return g(s);
> end;
> $$ language plpgsql;
>
> create function g(t text) returns text as $$
> begin
>          let s = 'BOOM!';
>          return t;
> end;
> $$ language plpgsql;
>
> select f();
> CREATE VARIABLE
> CREATE FUNCTION
> CREATE FUNCTION
> server closed the connection unexpectedly
>         This probably means the server terminated abnormally
>         before or while processing the request.
>
> LOG:  server process (PID 55307) was terminated by signal 11:
> Segmentation fault
> DETAIL:  Failed process was running: select f();
>
>
> I believe it's a use-after-free error, triggered by assigning a new
> value to s in g(), thus making t a dangling pointer.
>
> After reconnecting I get a scary error:
>
> postgres=# select f();
> ERROR:  compressed pglz data is corrupt
>

I am able to reproduce it, and I have a quick fix, but I need to
investigate i this fix will be correct

It's a good example so I have to always return a copy of value.

Regards

Pavel





>
> Best regards,
>
> --
> Sergey Shinderuk                https://postgrespro.com/
>
>