Re: passing parameters to CREATE INDEX

>> http://archives.postgresql.org/pgsql-hackers/2005-09/msg00851.php
> 
> Just to follow up on the discussion of that thread: what's been
> implemented is a way to store arbitrary name=value strings in an index's
> pg_class entry, and to make these available in a pre-parsed form through
> the index relcache entry.  However you'd have to be cautious about using
> the values directly for any fundamental index structure decisions,
> because ALTER INDEX will just change them without giving you an
> opportunity to modify the index in response.  So depending on what you
> are doing, you might need to store the "real" values in the index
> metapage, and set those values from the reloptions parameters only at
> ambuild() time.  This would mean that ALTER INDEX + REINDEX would be the

I see. There is one more problem: pluggable parameters for index. For example, 
the parameter needed for tsearch2 (size of signature) isn't useful for others 
modules/opclasses. Another issue, GiST (and GIN too) doesn't have metapage at 
all for now, it's not a problem, but until now it wasn't needed. I think, we may 
can add to pg_opclass's definition method/parameter name and create some API 
(may be, index specific) to propagate parameter's to module's interface 
functions to index.


> Also: as of CVS tip ginoptions() accepts FILLFACTOR but nothing is done
> with it.  Can you do something useful with FILLFACTOR in GIN?

Now GIN is nested B-Tree: B-tree for entries (lexemes for tsearch2) and B-Tree 
for ItemPointers per entry if entry is popular enough. So fillfactor may be used 
as usual.
Small advertising :) : http://www.sigaev.ru/gin/GinStructure.pdf

-- 
Teodor Sigaev                                   E-mail: teodor@sigaev.ru
  WWW: http://www.sigaev.ru/