On Thu, Oct 17, 2019 at 11:52:39AM +0200, Tom Lane wrote:
Morris de Oryx <morrisdeoryx@xxxxxxxxx> writes:
Given that Amazon is bragging this week about turning off Oracle, it seems
like they could kick some resources towards contributing something to the
Postgres project. With that in mind, is the idea of defining dictionaries
within a table somehow meritless, or unexpectedly difficult?
Well, it'd just be totally different. I don't think anybody cares to
provide two separate definitions of common dictionaries (which'd have to
somehow be kept in sync).
As for why we did it with external text files in the first place ---
for at least some of the dictionary types, the point is that you can
drop in data files that are available from upstream sources, without any
modification. Getting the same info into a table would require some
nonzero amount of data transformation.
IMHO being able to load dictionaries from a table would be quite
useful, and not just because of RDS. For example, it's not entirely true
we're just using the upstream dictionaries verbatim - it's quite common
to add new words, particularly in specialized fields. That's way easier
when you can do that through a table and not through a file.
Having said that ... in the end a dictionary is really just a set of
functions implementing the dictionary API; where they get their data
from is their business. So in theory you could roll your own
dictionary that gets its data out of a table. But the dictionary API
would be pretty hard to implement except in C, and I bet RDS doesn't
let you install your own C functions either :-(
Not sure. Of course, if we expect the dictionary to work just like the
ispell one, with preprocessing the dictionary into shmem, then that
requires C. I don't think that's entirely necessary, thoug - we could
use the table directly. Yes, that would be slower, but maybe it'd be
sufficient.
But I think the idea is ultimately that we'd implement a new dict type
in core, and people would just specify which table to load data from.
regards
--
Tomas Vondra http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
