who calls database

[barmar@THINK.COM]

   Date: Tue, 21 Nov 89 16:44 CST
   From: dmitchell@backus.trc.amoco.com (Donald H. Mitchell)

   A Symbolics tech support person asked me if I had enabled the who calls
   database the other day.  I said I hadn't done anything explicit and that
   seemed to imply that I hadn't given their response.  Wanting to find out
   more I looked in my 7.2 documentation and saw that the database is
   automatically enabled by Set Site.  Is the documentation correct (and
   thus I inferred the wrong thing from the Symbolics rep's comment)?  Is
   it different for 7.4?

I don't know about 7.4, but in 7.2 the who-calls database is enabled when
setting the site.  However, it enables it in the :ALL mode, which means
that it only records callers in functions defined after enabling; it
doesn't go through the world building the who-calls database.  If you want
all callers in the database, you must use (SI:ENABLE-WHO-CALLS
:ALL-REMAKE).

   If I do :optimize world, will it automatically compress the who calls
   database or do I need to do that as a separate step?

No, Optimize World doesn't do this.  You have to call SI:COMPRESS-WHO-CALLS
explicitly.  By the way, we've run into some problems with this recently;
it would FEP out in some worlds due to mismanagement of some GC variables.