Re: BUG #19411: libpq 16.x exhibits a memory leak when connections are repeatedly created and destroyed

Matt Carter <Matt(dot)Carter(at)twosigma(dot)com> writes:
> Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> I think there are way too many moving parts here, and too few configuration details,
>> to allow assigning blame confidently.

> Thank you for taking the time to test this and for the feedback. Your C test showing no leak suggests the issue is specific to how psycopg2 uses libpq, not libpq itself. I apologize for not including enough environmental details. I used Kerberos/GSSAPI with SSL (TLS 1.2 connections). My connection string was: "postgresql://hostname/database" (no password, Kerberos auth).
> Your mention of "years ago libpq did leak memory while using GSSAPI encryption" is interesting because we ARE using GSSAPI/Kerberos authentication.

Interesting. I wondered about GSSAPI, but spinning up such an
environment is more work than I wanted to do on speculation.

> I can test with non-GSSAPI authentication to try to isolate that variable. I can also create a pure psycopg2 reproducer (without SQLAlchemy). I can also test whether disabling GSSAPI encryption (but keeping GSSAPI auth) changes the behavior. Would testing with GSSAPI authentication help narrow this down? I can also report this to the psycopg2 project if you think it's their issue.

Please try varying the connection type and encryption. I do suspect
this may be psycopg2's fault, but we lack enough data to pin blame
as yet.

regards, tom lane