Comment 42 for bug 264336

It does appear that these errors are triggered due to the per-segment limit being 32MB. People can work round this by either reducing the size of the segment in their application or by increasing the kernel limit using sysctl, this can be made permenant using files in /etc/sysctl.d. These should persist over an upgrade.

The default value in the kernel does not appear to have changed since Hardy at 32MB, so its not clear that we should change the default at the kernel level. It may be appropriate to ship a /etc/sysctl.d file to update this with postgres if its defaults require more than the default kernel limit. Else it may be a documentation issue for those configuring larger databases.