Hi, On 2022-08-07 09:24:40 +0530, Dilip Kumar wrote: > On Sat, Aug 6, 2022 at 9:36 PM Tom Lane <t...@sss.pgh.pa.us> wrote: > > > > Dilip Kumar <dilipbal...@gmail.com> writes: > > > On Fri, Aug 5, 2022 at 10:43 AM Dilip Kumar <dilipbal...@gmail.com> wrote: > > >> Yeah maybe it is not necessary to close as these unowned smgr will > > >> automatically get closed on the transaction end. > > > > I do not think this is a great idea for the per-relation smgrs created > > during RelationCopyStorageUsingBuffer. Yeah, they'll be mopped up at > > transaction end, but that doesn't mean that creating possibly tens of > > thousands of transient smgrs isn't going to cause performance issues.
I was assuming that the files would get reopened at the end of the transaction anyway, but it looks like that's not the case, unless wal_level=minimal. Hm. CreateAndCopyRelationData() calls RelationCreateStorage() with register_delete = false, which is ok because createdb_failure_callback will clean things up. But that's another thing that's not great for a routine with a general name... > Okay, so for that we can simply call smgrcloserellocator(rlocator); > before exiting the RelationCopyStorageUsingBuffer() right? Yea, I think so. > > I think RelationCopyStorageUsingBuffer needs to open and then close > > the smgrs it uses, which means that ReadBufferWithoutRelcache is not the > > appropriate API for it to use, either; need to go down another level. > > Not sure how going down another level would help, the whole point is > that we don't want to keep the reference of the smgr for a long time > especially in the loop which is interruptible. Yea, I'm not following either. Greetings, Andres Freund
