Re: NOT LIKE much faster than LIKE?

On Wed, Jan 11, 2006 at 09:39:47PM +0100, Andrea Arcangeli wrote:
> On Wed, Jan 11, 2006 at 12:40:32PM -0600, Jim C. Nasby wrote:
> > On Tue, Jan 10, 2006 at 02:44:47AM +0100, Andrea Arcangeli wrote:
> > > "cooperative" runs "WHERE kernel_version NOT LIKE '%% PREEMPT %%'", while
> > > "preempt" runs "WHERE kernel_version LIKE '%% PREEMPT %%'. The only difference
> >
> > One thing you could do is change the like to:
> >
> > WHERE position(' PREEMPT ' in kernel_version) != 0
>
> That alone fixed it, with this I don't even need the index (yet). Thanks
> a lot.

The fix is online already w/o index:

    http://klive.cpushare.com/?branch=all&scheduler=preemptive

Of course I'm still fully available to test any fix for the previous
LIKE query if there's interest.