Hi, I created a new patch that throws an exception if we try to call destroy on a dsm segment that is still in use. I added a function in dsm.h that returns a refcnt of a given dsm segment. The destroy function uses that refcnt getter to check if the dsm segment is in use.
2025년 6월 16일 (월) 오후 11:40, Nathan Bossart <nathandboss...@gmail.com>님이 작성: > > On Mon, Jun 16, 2025 at 09:02:22AM +0900, Sungwoo Chang wrote: > > 2025년 6월 14일 (토) 오전 6:50, Nathan Bossart <nathandboss...@gmail.com>님이 작성: > >> Could your use-case be handled with a DSA? On the other thread [0], we're > >> talking about adding a GetNamedDSA() function, which returns a DSA that you > >> can use to allocate and free shared memory as needed. In theory you could > >> even detach the DSA if you no longer needed it in a backend, although > >> that's probably unnecessary. > > > > My use-case requires access to the shared memory object through a named key. > > Even if we migrate the code to NamedDSA, within the DSA we will need some > > sort > > of a map between the named key and the object to access. So, I think > > NamedDSA > > won't be the solution. > > Right, you'd need some other shared space for the DSA pointers. In the > other thread, I'm using a dshash table (created via GetNamedDSMHash()) to > store those for test_dsm_registry [0]. There are probably other ways to do > this. > > > How about when we call destroy, we check if there are other processes > > attached to it and if so, we throw an exception? I checked C++ boost > > interprocess library [0], and it looks like that's the way boost does. > > This way, we can avoid the aforementioned "partitioned" scenario. > > That might work. > > [0] https://postgr.es/m/aEyX-9k5vlK2lxjz%40nathan > > -- > nathan
v4-0001-add-detach-and-destroy-for-dsm_registry.patch
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