Shridhar Daithankar wrote: > There seem to be two objections to mmap. > > 1. If a backend from last crashed running postmaster exists then it might > have file etc. open and that is in general not such a good idea > > 2. For replacing stdio for data and WAL files with mmap, mmap does not > guarantee order of IO which defeats WAL.
[...] > Did I miss something? Yes: based on everything that I've read on the subject, you can't change the size of a shared memory segment allocated by mmap(). It's unlikely that mremap() will propgate changes to all other processes that share the same area, since it can (if passed the proper flags) return a starting address that differs from the current starting address. And since propagation of the shared memory area is done via duplication of the parent's page tables by the kernel at fork() time, new segments would not be picked up by existing backends -- only new ones -- and then only if the postmaster is the process that allocates them. -- Kevin Brown [EMAIL PROTECTED] ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])