Re: Shared memory leak on DSM slot exhaustion

On Thu, Jan 30, 2020 at 4:54 AM Thomas Munro <thomas(dot)munro(at)gmail(dot)com> wrote:
> As reported over on pgsql-general[1], we leak shared memory when we
> run out of DSM slots. To see this, add the random-run-out-of-slots
> hack I showed in that thread, create and analyze a table t(i) with a
> million integers, run with dynamic_shared_memory_type=mmap, and try
> SELECT COUNT(*) FROM t t1 JOIN t t2 USING (i) a few times and you'll
> see that pgbase/pg_dynshmem fills up with leaked memory segments each
> time an out-of-slots errors is raised. (It happens with all DSM
> types, but then the way to list the segments varies or there isn't
> one, depending on type and OS.) Here's a draft patch to fix that.

Whoops. The patch looks OK to me.

--
Robert Haas
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