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Re: newbie : BIND VARIABLES

From: cava123 <cava123_at_noos.fr>
Date: Mon, 17 Jun 2002 01:29:16 +0200
Message-ID: <3D0D1F4C.C4333D4@noos.fr>


Jim Kennedy a écrit :

> Bind variables are place holders in DML (eg select .. from mytable where
> field1:=hvField1)

>>Only in PL/SQL code ? Which V$ vues give the information if the code use bind
variables or not ? (EXPLAIN PLAN can help to detect if variables are bound or not -what does HASH JOIN mean- ?

>
> Without bind variables you are forcing Oracle to serielize on a latch and
> you are causing earch and every statement to be reparsed.(high CPU) It will
> mean each sql statement will take longer. Once the statement is parced, is
> you use bind variables, then it does not need to be reparsed and the
> execution plan does not need to be redone.
> Jim
> "cava123" <cava123_at_noos.fr> wrote in message
> news:3D0CB6CC.B3A0C34_at_noos.fr...
> > Hi all,
> > We have to use "bind variables" : What does bind variables means exactly
> > ? relation ship with performance ? and how I can see if it used or not ?
> > (V$SQLAREA,V$SQL,V$SESSION, ...)
> > I have also execute an ALTER SESSION SET AUTOTRACE TRACEONLY EXPLAN PLAN
> > for .... and get 'HASH JOIN' : What does it mean HASH JOIN and HASH
> > TABLES ?
> > Thanks
> >
> >
Received on Sun Jun 16 2002 - 18:29:16 CDT

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