Re: Simple join optimized badly?

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