Re: BUG #6327: Prefix full-text-search fails for hosts with complicated names

Marcin(dot)Kasperski(at)mekk(dot)waw(dot)pl writes:
> Synopsis
> =========

> 'goog:*' matches google.com
> but
> 'e-goog:*' does not match e-google.com

The reason for this seems to be that the pattern is treated as a
hyphenated word:

regression=# select TO_TSQUERY('english', 'e-goog:*');
to_tsquery
-------------------------------
'e-goog':* & 'e':* & 'goog':*
(1 row)

but the hostname isn't:

regression=# select TO_TSVECTOR('english', 'See e-google.com');
to_tsvector
--------------------------
'e-google.com':2 'see':1
(1 row)

If you change the text so it's not recognized as a hostname, you get
lexemes that would match the query:

regression=# select TO_TSVECTOR('english', 'See e-google com');
to_tsvector
---------------------------------------------
'com':5 'e':3 'e-googl':2 'googl':4 'see':1
(1 row)

Possibly we could fix this by hacking the ts parser so that it would
also apply the hyphenated-word rules to a hostname containing a dash.

In general though, there are always going to be cases where prefix
match doesn't work because of dictionary transformations ...

regards, tom lane