Re: [COMMITTERS] pgsql: Modify the isolation tester so that multiple sessions can wait.

On Wed, Apr 27, 2016 at 1:51 PM, Alvaro Herrera
<alvherre(at)2ndquadrant(dot)com> wrote:
> Robert Haas wrote:
>> Modify the isolation tester so that multiple sessions can wait.
>
> Mikael was kind enough to set up an OpenBSD 5.9 buildfarm member, and
> it's been failing in isolationtester. (I kindly accepted my suggestion
> to put it to run even though it is failing so that we could look at the
> logs). I think this commit is the problem; see the backtrace he sent me
> on private email.
>
> #0 0x00001e18c62af87a in thrkill () at <stdin>:2
> 2 <stdin>: No such file or directory.
> in <stdin>
> (gdb) bt
> #0 0x00001e18c62af87a in thrkill () at <stdin>:2
> #1 0x00001e18c62aaf39 in *_libc_abort () at
> /usr/src/lib/libc/stdlib/abort.c:52
> #2 0x00001e18c62a7838 in *_libc_memcpy (dst0=0x0, src0=0x6, length=0) at
> /usr/src/lib/libc/string/memcpy.c:65
> #3 0x00001e16a7904a7e in run_permutation (testspec=0x1e16a7d08b20,
> nsteps=11, steps=Variable "steps" is not available.
> ) at isolationtester.c:617
> #4 0x00001e16a7904d7c in run_testspec (testspec=0x1e16a7d08b20) at
> isolationtester.c:369
> #5 0x00001e16a79053ce in main (argc=Variable "argc" is not available.
> ) at isolationtester.c:251

That looks like malloc() returned NULL. I noticed when writing that
patch that isolationtester has never had any checks for malloc
returning NULL, which is bad, and probably worth fixing, but I didn't
choose to stop and fix it at that time.

I don't know off-hand why you see that problem starting at this commit
and not before, or why it doesn't show up on other machines.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company