Re: MacOS X Shared Buffers (SHMMAX)?

"Command Prompt, Inc." <pgsql-general(at)commandprompt(dot)com> writes:
> I was able to pull down the source for the Kernel, and increased the
> SHMMAX by a factor of 16. Upgraded to the new Kernel and I am now able to
> get safely 512 connections, even up around 900, but bumping it up to 1024,
> I run into the following error:

> PGSTATBUFF: recvfrom(2): Resource temporarily unavailable
> DEBUG: statistics collector process (pid 1988) exited with exit code 1

> ...which then repeats itself infinitely until the calling process is
> stopped. ;)

[ scratches head... ] "Resource temporarily unavailable" is EAGAIN
according to /usr/include/sys/errno.h on my OSX machine. But the man
page for recvfrom doesn't mention any plausible reasons for EAGAIN to
be signaled. select() just told us there was data available on the
socket, so WTF? Could this be a kernel bug?

You could try modifying pgstat.c to continue its loop rather than
exiting after it gets a recvfrom error. But if the error condition
recurs that'll just put pgstat.c into an infinite loop, so I'm not
sure this is any solution --- just a way of gathering more data.

regards, tom lane