Re: Where can I get a complete list of all SQL Hints?

tonym101_at_hotmail.com (TM) wrote in message news:<7b718442.0306181730.2ab7f95e_at_posting.google.com>...
> "Noons" <wizofoz2k_at_yahoo.com.au.nospam> wrote in message news:<3eeb195c$0$16255$afc38c87_at_news.optusnet.com.au>...
>
> > For the same reason SQL Server, Sybase
> > and DB2 have the same feature: the CBO is NOT
> > so great.
>
> DB2 doesn't have hints. At least, not DB2 UDB For Multiplatforms
> (UNIX, Linux, Windows, OS/2)... i.e. the common code base flavour
> that's gobbling market share. DB2 UDB is widely recognised as having
> the leading optimizer though. Oracle still needs hints because it's
> playing catch up.
>
> Believe DB2 For OS/390 has some feature once billed as vaguely akin to
> "hints" but which in fact involves storing the hint in the catalog.
> Maybe that's what you meant. This still doesn't involve coding hints
> into your SQL though.
>
>
> TM

Then what's DB2's Optimizer Level (1 to 9 if I remember right)?

DB2's optimizer is neither smarter nor dumber, but more rigid in its behavior and more abstract. For a SQL statement, you can only specify level 1 to level 9 to adjust the level of rewrite done by DB2's optimizer. But which level's best? God knows.

Just my cents.

Bosco Received on Thu Jun 19 2003 - 04:49:53 CDT