On Fri, Feb 14, 2020 at 4:47 AM Alvaro Herrera <alvhe...@2ndquadrant.com> wrote: > So, you said lseek() is faster than fstat, and we would only use the > latter because we want to avoid the file position jumping ahead, even > though it's slower. But if the next read/write is not going to care > about the file position because pread/pwrite, then why not just do one > lseek() and not worry about the file position jumping ahead? Maybe the > API could offer this as an option; caller can say "I do care about file > position" (a boolean flag) and then we use fstat; or they can say "I > don't care" and then we just do a single lseek(SEEK_END). Of course, in > Windows we ignore the flag since we can do it in the fast way. > > pg_file_size(int fd, bool careful) > > Let's have the function comment indicate that -1 is returned in case of > failure.
Reviving an old thread... yeah, we should probably figure out if we still want a central fd size function and how it should look, but in the meantime, we might as well have slru.c using pread/pwrite as already agreed, so I went ahead and pushed that part.
