We've seen something similar, but not with a 'LIKE'.
A query based on an INT field would table scan if the value was over the
32 bit limit.
We had an issue open for a long time and they just ended up saying
'sorry, we can't do anything about that'.
Andre
________________________________
From: info-ingres-bounces@[EMAIL PROTECTED]
on behalf of Roy Hann
Sent: Tue 08/07/2008 3:42 AM
To: info-ingres@[EMAIL PROTECTED]
[Info-Ingres] LIKE with oversize pattern forces table scan?
One of my colleagues is dealing with a Unicenter Helpdesk site and has a
call open with CA (remember them?). The problem is that he's noticed
that when a query includes a LIKE condition where the pattern contains
no wild-card characters but the pattern is longer than the declared
length of the column being tested, Ingres invariably does a table scan,
even though there's a usable index.
CA tech sup****t have responded "Ingres has always behaved this way, and
as far as we know, it always will, because of the way the architecture
is designed."
I can buy the first bit of that, but the second part sounds like
baloney. Can anyone sup****t or refute that?
(Privately, it seems to me that it would be more correct to re****t an
error when the pattern is too long to match any data. But that is
another rant for another day.)
Roy
--
UK Ingres User Association Conference 2009 will be on Tuesday June 9, 2009
Go to http://www.iua.org.uk/join
to get on the mailing list.
_______________________________________________
Info-Ingres mailing list
Info-Ingres@[EMAIL PROTECTED]
|
