Authoriy Work Implications?

["Stephen McLaughlin" <sMcLaughlin at sfpl dot org>]

I'm about to do a massive replacement of authority records, and I want
to make sure I understand all the potential side-effects. Here's what's
on tap:

In our previous (DRA) system, there was one authority file, so only one
name authority record was needed, since it served as both a name and a
subject-name authority. When we migrated to Innovative, we were unable
to distinguish pure name authorities from name + subject authorities, so
we dumped ALL the name authorities in with the subject authorities.

This, of course, hugely bloated our subject authority file, so we sent
our entire bibliographic database off to OCLC for MARS authority
processing. They updated the bib records (which have been loaded already
into the database, overlaying the original versions) and sent us files
with the appropriate name and subject authority records. Now I need to
swap out the new authorities for the old ones.

I have devised a somewhat complex process that is intended to preserve
certain local headings, as well as authorities loaded since the bib
extract (now several months ago - there was a lot of clean-up after the
loading of the bib records, but we won't go into that right now!).
Because I don't want to fill up the bibtemp file, I will be loading the
authority records in smallish batches (probably about 50,000 per day is
the maximum, based on past experience). What worries me is this: Will
there be any sort of an impact on the overnight headings reports (and
consequently on system performance) from dumping 50,000 authority
records a day over several days into the database? I'm afraid I do not
have a good grasp of how the headings reports work, when flipping of
headings in bib records is invoked by a new authority record, and so
forth, to understand the possible side-effects of loading so many
authority records into the database.

I would be very grateful for any advice, warnings, suggestions, horror
stories or tales with happy endings that may help guide me as I work my
way through what promises to be a highly, um, entertaining experience!

Many thanks!

Steve McLaughlin
San Francisco Public Library
smclaughlin at sfpl dot org