Re: Total estimated I/O cost for statement - 11-02-2011 , 03:45 PM
On Nov 3, 3:39*am, 1dg618 <1dg... (AT) gmail (DOT) com> wrote:
Unfortunately there are no *good* books. The Jeffery Garbus book is
the best of the bad lot. For the level of your questions, it will
increase your understanding. No question that you should know as much
as you can about your platform, so that you can administer it better.
It is true that platform-specific info will allow you to take
advantage of that, but that is at the higher end, let's say the last
20% of performance. The issues here are not internals or platform-
specific. They fall squarely within the first 80%. Really, they are
Data Modelling errors. Sybase is by far the best at taking whatever
you have modelled and making the most of it: the better/more standard-
compliant your model, the better Sybase will handle it.
- if you add the FK Constraint the QP will correct itself (eg. change
from merge join to nested loop join; otherwise MJ is probably the best
it can do)
- if you correct the code, you can examine one table only
- if you correct the nullable FK (serious error) the problem
None of that is "taking advantage of platform-specific info"
Re: Total estimated I/O cost for statement - 11-04-2011 , 07:11 AM
On Nov 2, 4:45*pm, Derek Asirvadem <derek.asirva... (AT) gmail (DOT) com> wrote: