On Fri, Sep 21, 2018 at 4:06 PM Tom Lane <t...@sss.pgh.pa.us> wrote: > Thomas Munro <thomas.mu...@enterprisedb.com> writes: > > ... There may be ways to fix the dsm_resize() path > > based on the observation that you don't need to fallocate() if you > > made the mapping smaller, and if you made it bigger then you could > > always undo that on error (or not) and you haven't thrown away any > > data. Hmm... I note that there are actually no callers of > > dsm_resize(), and it's not implemented on Windows or SystemV.
Erm, actually you probably only need to do ftruncate() *or* posix_fallocate(), depending on the direction of the resize. Doing both is redundant and introduces this theoretical hazard (in practice I'd be surprised if fallocate() really can fail after you shrank a file that was already fully allocated). > Why would we fix it rather than just removing it? I assumed we wouldn't remove an extern C function extension code somewhere might use. Though admittedly I'd be surprised if anyone used this one. -- Thomas Munro http://www.enterprisedb.com
