Re: Initial ugly reverse-translator - Mailing list pgsql-general

From Tom Lane
Subject Re: Initial ugly reverse-translator
Date
Msg-id 10234.1208623093@sss.pgh.pa.us
Whole thread Raw
In response to Re: Initial ugly reverse-translator  (Craig Ringer <craig@postnewspapers.com.au>)
Responses Re: Initial ugly reverse-translator  (Oleg Bartunov <oleg@sai.msu.su>)
Re: Initial ugly reverse-translator  (Craig Ringer <craig@postnewspapers.com.au>)
List pgsql-general
Craig Ringer <craig@postnewspapers.com.au> writes:
> Tom Lane wrote:
>> I don't really see the problem.  I assume from your reference to pg_trgm
>> that you're using trigram similarity as the prefilter for potential
>> matches

> It turns out that's no good anyway, as it appears to ignore characters
> outside the ASCII range. Rather less than useful for searching a
> database of translated strings ;-)

A quick look at the pg_trgm code suggests that it is only prepared to
deal with single-byte encodings; if you're working in UTF8, which I
suppose you'd have to be, it's dead in the water :-(.  Perhaps fixing
that should be on the TODO list.

But in any case maybe the full-text-search stuff would be more useful
as a prefilter?  Although honestly, for the speed we need here, I'm
not sure a prefilter is needed at all.  Full text might be useful
if a LIKE-based match fails, though.

>> (And besides, speed doesn't seem like the be-all and end-all here.)

> True. It's not so much the speed as the fragility when faced with small
> changes to formatting. In addition to whitespace, some clients mangle
> punctuation with features like automatic "curly"-quoting.

Yeah.  I was wondering whether encoding differences wouldn't be a huge
problem in practice, as well.

            regards, tom lane

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