RE: Must Read for Every Developer and DBA

2002-09-06 Thread Cary Millsap
...But only on the first execution of a session. It's a bug. Test (credit Jonathan Lewis): 0. Set up "select c1, c2 from t1 where c1=:bind1" where different bind1 values would motivate different execution plans if we used literals. E.g., insert only a few rows where c1=5, and thousands of rows w

RE: Must Read for Every Developer and DBA

2002-09-06 Thread Khedr, Waleed
Histograms are useless if the optimizer does not know the exact value in the bind variable during a one pass execution plan (static execution plans). But if the execution path could be delayed to a later phase (bind stage) then probably the execution plan could be altered based on the value in the

RE: Must Read for Every Developer and DBA

2002-09-06 Thread BALA,PRAKASH (Non-HP-USA,ex1)
This is true in 8i. But in 9i, this has changed per Gaja. Even if bind variables are used, it will use histograms if histograms are present. Prakash -Original Message- Sent: Friday, September 06, 2002 10:23 AM To: Multiple recipients of list ORACLE-L I thought that bind variables were

RE: Must Read for Every Developer and DBA

2002-09-06 Thread Fink, Dan
Another issue is the ability of the CBO to use bind variables. Until recently (9i, I think), the CBO would use a single execution plan for a statement with bind variables, even if the data values of the bind variables actually indicated that the plan was not optimal. For example, a query that retr

RE: Must Read for Every Developer and DBA

2002-09-06 Thread Naveen Nahata
>I thought that bind variables were faster >but you always have to ensure that >if you're accessing by data which may be >heavily skewed and histograms would >usually help you may not want to use >bind variables as they will disable >the use of histograms. What will happen if i don't use bind

RE: Must Read for Every Developer and DBA

2002-09-06 Thread DENNIS WILLIAMS
Vikas I had a developer recently report that his program was actually a little faster by not using bind variables. Once I stopped screaming I calmly explained the following. The issue isn't whether bind variables are faster or not, but rather what SQL statements that don't use bind variables

RE: Must Read for Every Developer and DBA

2002-09-06 Thread Nicoll, Iain \(Calanais\)
I thought that bind variables were faster but you always have to ensure that if you're accessing by data which may be heavily skewed and histograms would usually help you may not want to use bind variables as they will disable the use of histograms. In saying that it doesn't look as though that w

Must Read for Every Developer and DBA

2002-09-06 Thread Vikas Khanna
Hello Vikas, As You said We should always make use of bind variables as it executes faster as compare to the statements where we do not make use of bind variables. Q1) Can you please take a more specific example as how a statement can be altered to make use of bind variable. Q2) I made use of S