> Furthermore, after trying to just index on a 8191-character long substring
> of the resume, I run into the following:
> ERROR: btree: index item size 3948 exceeds maximum 2713
> The only way I could actually get the index created was to substring the
> body of the resumes down to 2k. I also later tried using HASH rather than
> BTREE, which worked, but none of these solutions really appreciably
> increased performance in the way we were hoping.
>
> Are these known and accepted limitations of the current 7.1
> implementation, or am I doing something terribly wrong? ;)
Hmm. I'm pretty sure that a single index on the entire contents of a
resume *as a single field* is close to useless. And an index on an 8k
piece is also useless. Presumably you really want an index covering each
significant word of each resume, in which case you would not run into
the 4k limit (or 2k limit? it is documented somewhere) on the size of an
*index* field (which is still a limitation on PostgreSQL built with the
standard 8k block size. Of course, you can build with a larger block
size).
hth
- Thomas
