Building hash table times for large files

[Rob Bosch]

I'm running pre4 on a 77GB file.  It seems like the hash table is taking a
long time to be built.  I'm not sure what is involved in this step but as an
example the following is logged during a run:

send_files(11, priv1.edb) 
send_files mapped priv1.edb of size 79187419136 
calling match_sums priv1.edb 
<f.st...... priv1.edb 
hash search b=131072 len=79187419136 
built hash table for entries 0 - 52427 
built hash table for entries 52428 - 104855 
built hash table for entries 104856 - 157283 
built hash table for entries 157284 - 209711

The first two hash table entries (0 - 52427 and 52428 - 104855) took only a
few minutes.  The next two entries written to the log file have taken
several hours.  

Does this make sense?  Should the entries take so long to be built?

Rob