Jim C. Nasby wrote:
(snippage)... but we'll never get any progress so long as every
time hints are brought up the response is that they're evil and should
never be in the database. I'll also say that a very simple hinting
language (ie: allowing you to specify access method for a table, and
join methods) would go a huge way towards enabling app developers to get
stuff done now while waiting for all these magical optimizer
improvements that have been talked about for years.
It is possibly because some of us feel they are evil :-) (can't speak
for the *real* Pg developers, just my 2c here)
As for optimizer improvements well, yeah we all want those - but the
basic problem (as I think Tom stated) is the developer resources to do
them. As an aside this applies to hints as well - even if we have a
patch to start off with - look at how much time bitmap indexes have been
worked on to get them ready for release....
Personally I don't agree with the oft stated comment along the lines of
"we will never get the optimizer to the point where it does not need
some form of hinting" as:
1/ we don't know that to be a true statement, and
2/ it is kind of admitting defeat on a very interesting problem, when in
fact a great deal of progress has been made to date, obviously by people
who believe it is possible to build a "start enough" optimizer.
best wishes
Mark
