Thread

Re: [HACKERS] Re: [BUGS] General Bug Report: Bug in optimizer

Bruce Momjian <maillist@candle.pha.pa.us> — 1999-03-18T18:46:16Z

> Bruce Momjian wrote:
> > 
> > Let me tell you why I don't think this is a bug.  The optimizer will
> > choose ordered results over unordered results if the costs are the same.
> > In this case, the cost of the query is zero, so it chose to use the
> > index because the index produces an ordered result.
> > 
> > This works well for un-vacuumed tables, because it thinks everything is
> > zero cost, and chooses the index.
> 
> Agreed, this is ok as long as
> 
> vac=> create table table1 (field1 int);
> CREATE
> vac=> insert into table1 values (1);
> INSERT 1583349 1
> vac=> create index i_table1__field1 on table1 (field1);
> CREATE
> vac=> explain select * from table1 where field1 = 1;
> NOTICE:  QUERY PLAN:
> 
> Seq Scan on table1  (cost=1.03 size=1 width=4)
> 
> - SeqScan is used for small tables.
> 
> So, only bug reported is left.
> 

Can you get on IRC now?  Why are you up so late?

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