> Bruce Momjian wrote:
> >
> > My guess is that the creation of the index updates the table size
> > statistics.
>
> Yes.
>
> > However, when I see zero size, I don't know if it is accurate, or if
> > someone has added rows since the last vacuum/index creation, so I think
> > it is correct to use an index on a zero-length table if it is
> > appropriate. If the size is 1, I will assume that number is accurate,
> > and do a sequential scan.
> >
> > Does that make sense?
>
> Yes. But we have to fix SeqScan for field1 = -1...
The basic problem is that the -1 is stored as:{ EXPR :typeOid 0 :opType op :oper { OPER :opno 558
:opid 0 :opresulttype 23 } :args ( { CONST :consttype 23 :constlen 4
:constisnullfalse :constvalue 4 [ 4 0 0 0 ] :constbyval true } )
This is clearly undesirable, and causes the optimizer to think it can't
use the index.
Is this bug report for 6.4.*, or did are you running the current
development tree? I assume you are running 6.4.*, and am surprised this
did not show as a larger problem.
I will look in the grammer for a fix. This should come across as a
single -4 constant.
-- Bruce Momjian | http://www.op.net/~candle maillist@candle.pha.pa.us | (610)
853-3000+ If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill,
Pennsylvania19026
