Text field performance

[Glen Parker <glenebob@xxxxxxxxxx>]

We are having some performance issues we think may be related to large 
text field values, and many records.  So, a couple questions...

1) Are text values always stored in the companion text file, or only if 
they exceed a certain size?  What size?

2) When the query executer reads tuples during a query, does it always 
read the text companion file too?  For example, the executer finds an 
index match and then goes after the heap tuple to continue field 
matching.  Now, assuming the query does not contain any conditions 
involving a text field, does the executer read the text field in even if 
the tuple does not match and won't be included in the result set?

3) Is there any eqivelent to the CLUSTER functionality for text 
companion files?  Is there any such thing planned?  What's the best way 
to reduce fragmentation in a text companion file?

TIA

-Glen