"Simon Riggs" <[EMAIL PROTECTED]> writes:
> ... BMI is not useful at all
> for PKs, whilst GIT is specifically designed to handle them.

This seems a strange statement, because GIT doesn't look particularly
efficient for unique indexes AFAICS.  In the worst case you'd have to
look individually at each tuple on a heap page to check for uniqueness
conflict (no binary search, because you couldn't assume they are
ordered).

> B-TREE INDEXES (Integers) 

> Rows/value    Best time       Size in blocks
> 10000000      49s             21899
> 1000000               49s             21899
> 100000                49s             21899
> 10000         47s             21899
> 1000          43s             21899
> 100           38s             21899
> 10            38s             21899
> 1             33s             21899

Surely the GIT code failed to kick in at all here?  That's just about
exactly the index size I'd expect for 10 million integers with the
existing btree code (at least when MAXALIGN=4).

                        regards, tom lane

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