Re: Full-text search default vs specified configuration

On Fri, 22 Feb 2008, Richard Huxton wrote:

> Tom Lane wrote:
>> Richard Huxton <dev@archonet.com> writes:
>>> Would there be any support for two changes in 8.4 though?
>> 
>>> 1. Tag tsvector/tsquery's with the (oid of) their configuration?
>> 
>>> 2. Either warn or require CASCADE on changes to a configuration/dictionary 
>>> that could impact existing indexes etc.
>> 
>> IIRC, the current behavior is intentional --- Oleg and Teodor argued
>> that tsvector values are relatively independent of small changes in
>> configuration and we should *not* force people to, say, reindex their
>> tables every time they add or subtract a stopword.  If we had some
>> measure of whether a TS configuration change was "critical" or not,
>> it might make sense to restrict critical changes; but I fear that
>> would be kind of hard to determine.
>
> Well, clearly in my example it didn't impact operation at all, but it's an 
> accident waiting to happen (and more importantly, a hard one to track down). 
> It's like running SQL-ASCII encoding, everything just ticks along only to 
> cause problems a month later.
>
> What about the warning: "This may affect existing indexes - please check". 
> Would that cause anyone problems?
>
> What worries me is that it might take 10 messages on general/sql list to 
> figure out the problem. This was reported as "words with many hits causes 
> problems".

He just didn't read documentation thoroughly.

>
> Maybe it's just a matter of getting the message out: "always specify the 
> config or never specify the config".

Probably, just stress this in documentation.

    Regards,        Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83