On 10/22/2018 10:00 PM, Amit Langote wrote:
>
> After observing the test case in the provided log, I managed to reproduce
> it with the following:
>
> create table foo (a int primary key, b int);
> create table bar (a int references foo on delete cascade, b int);
> insert into foo values (1, 1);
> insert into foo values (2, 2);
> alter table foo add c int;
> alter table foo drop c;
> delete from foo;
> server closed the connection unexpectedly
> This probably means the server terminated abnormally
> before or while processing the request.
> The connection to the server was lost. Attempting reset: Failed.
>
> Analyzing this crash, I located the bug down to GetTupleForTrigger(), but
> perhaps it's really in heap_expand_tuple() / expand_tuple(), where the
> value of trigger tuple's t_self is being switched from a valid one to an
> invalid value.
>
> In heaptuple.c: expand_tuple()
>
>
> ItemPointerSetInvalid(&((*targetHeapTuple)->t_self));
>
>
> FWIW, attached patch fixes this for me. Adding Andrew whose recent commit
> 7636e5c60f [1] seems to have introduced the heap_expan_tuple call in
> GetTupleForTrigger. Maybe, he can better judge a fix for this.
>
Thanks. I think the line in expand_tuple is a thinko and we should
change it, rather than change GetTupleForTrigger().
Here is a patch that does that and also adds your test case to the
regression tests.
cheers
andrew
--
Andrew Dunstan https://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
