Andres Freund <and...@anarazel.de> writes: > On 2017-10-02 18:33:17 -0400, Tom Lane wrote: >> I'm kind of surprised that machine B doesn't show obvious tanking in this >> test given that msync() makes it suck so badly at copying a database. >> I wonder what is different from the kernel's standpoint ... maybe the >> sheer number of different files mmap'd by a single process during the >> copy?
> Yea, that's curious. I've really no clue about OSX, so pardon my > question: With HEAD and CREATE DATABASE, is it IO blocked or kernel cpu > blocked? What I saw was that the backend process was consuming 100% of (one) CPU, while the I/O transaction rate viewed by "iostat 1" started pretty low --- under 10% of what the machine is capable of --- and dropped from there as the copy proceeded. I did not think to check if that was user or kernel-space CPU, but I imagine it has to be the latter. regards, tom lane -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers