On Sat, Sep 22, 2018 at 4:52 PM Amit Kapila <amit.kapil...@gmail.com> wrote: > On Sat, Sep 22, 2018 at 2:28 AM Andres Freund <and...@anarazel.de> wrote: > > On 2018-09-22 08:54:57 +1200, Thomas Munro wrote: > > > On Fri, Sep 21, 2018 at 4:43 PM Tom Lane <t...@sss.pgh.pa.us> wrote: > > > > Unless it looks practical to support this behavior in the Windows > > > > and SysV cases, I think we should get rid of it rather than expend > > > > effort on supporting it for just some platforms. > > > > > > We can remove it in back-branches without breaking API compatibility: > > > > > > 1. Change dsm_impl_can_resize() to return false unconditionally (I > > > suppose client code is supposed to check this before using > > > dsm_resize(), though I'm not sure why it has an "impl" in its name if > > > it's part of the public interface of this module). > > > 2. Change dsm_resize() and dsm_remap() to raise an error conditionally. > > > 3. Rip out the DSM_OP_RESIZE cases from various places. > > > > > > Then in master, remove all of those functions completely. However, > > > I'd feel like a bit of a vandal. Robert and Amit probably had plans > > > for that code...? > > > > Robert, Amit: ^ > > I went through and check the original proposal [1] to see if any use > case is mentioned there, but nothing related has been discussed. I > couldn't think of much use of this facility except maybe for something > like parallelizing correalated sub-queries where the size of outer var > can change across executions and we might need to resize the initially > allocated memory. This is just a wild thought, I don't have any > concrete idea about this. Having said that, I don't object to > removing this especially because the implementation doesn't seem to be > complete. In future, if someone needs such a facility, they can first > develop a complete version of this API.
Thanks for looking into that. Here's a pair of draft patches to disable and then remove dsm_resize() and dsm_map(). -- Thomas Munro http://www.enterprisedb.com
0001-Desupport-dsm_resize-and-dsm_remap.patch
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0002-Remove-dsm_resize-and-dsm_remap.patch
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