On 13-05-2011 19:20:44 +0200, Fabian Groffen wrote:
> Changeset: fc6142f33071 for MonetDB
> URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=fc6142f33071
> Modified Files:
>       configure.ag
>       gdk/gdk_utils.mx
> Branch: default
> Log Message:
> 
> memory: drop getrlimit code block

This change improved performance dramatically on the Mac:
http://monetdb.cwi.nl/testing/projects/monetdb/testweb/web/testgrid.php?serial=40197:fc6142f33071,40195:dcb51041c4a0&module=clients,geom,monetdb5,template,sql&targets=GNU-Darwin-x86_64-propcheck&order=platform,compiler,arch

Given the extreme performance win, should we consider backporting it to
Apr2011 branch?

> The getrlimit approach was meant to detect memory-limited environments,
> however, in practice it never does what it was supposed to do (except on
> Solaris).
> 
> On Darwin, the data size is by default set to 6MiB, causing a default of
> 6MiB memory to be detected.  We can in reality allocate much more than
> that.  The OS uses it as hint for victim choosing when memory shortage
> occurs anyway.  On Linux the limit is never respected.  In short, nice
> idea, but it doesn't quite work out as intended, and only seems to
> confuse.
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