Re: PQexec() hangs on OOM

On Mon, Sep 7, 2015 at 8:43 PM, Michael Paquier <michael.paquier@gmail.com>
wrote:

> On Mon, Sep 7, 2015 at 10:41 PM, Michael Paquier wrote:
> > In any case, attached are two patches:
> > - 0001 adds the OOM/failure handling for the BIND and COPY start
> > messages. This time the connection is not dropped. After a failure,
> > successive commands work as well, this addresses the previous issue
> > you reported.
> > - 0002 is a cleanup bonus, getRowDescriptions and getAnotherTuple have
> > some dead code that I think would be better removed, those are
> > remnants from a copy/paste from the similar code of protocol 2.
>
> And I forgot... Attached is a simple program to test BIND messages.
>

Still the same test fails for me.

postgres=# copy t1 from stdin;
out of memory
postgres=# copy t1 from stdin; --hangs here

It hangs in second statement, basically I think you can't change the
state to PGASYNC_BUSY on failure in case of copy in below code.

+ case PGASYNC_FATAL:
+ res = NULL;
+ /*
+ * Set the state back to BUSY, allowing parsing to proceed to
+ * consume messages coming from the server.
+ */
+ conn->asyncStatus = PGASYNC_BUSY;
+ break;

I think you need to keep the state as PGASYNC_COPY_*, so that
the pending data can be discarded.

With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com