* Considering the database is loaded separately for each session, does
this also imply that each running backend has a separate dictionary
stored in memory?
Yes.
As for downsides, I only really see two:
* Tracking updates of dictionaries - but it's reasonable to believe
that new connections get open more often than the dictionary gets
updated. Also, this might be easily solved by stat()-ing the dictionary
file before starting up session, and only have the server reload it if
there's a notified change.
* Possibly complicated to implement?
Keeping dictionary up to date - it's a most difficult part here. Configuration
of dictionary might be done by ALTER command - so, parent process (and all
currently running backends) should get that information to reload dictionary.
As for my second question, is it possible to use functions in tsearch2?
For example, writing my own stemmer in PL/pgSQL or in C as a postgres
function.
Yes, of course, you can develop your dictionary (-ies) and parser. Dut only in
C, because they are critical for performance.
--
Teodor Sigaev E-mail: teodor@xxxxxxxxx
WWW: http://www.sigaev.ru/
