Christo Du Preez <christo(at)mecola(dot)com> writes:
> On my laptop the explain analyze looks like this:
> "Index Scan using fki_layertype_parentid on layertype (cost=0.00..8.27
> rows=1 width=109)"
> " Index Cond: (parentid = 300)"
OK ...
> and on the problem server:
> "Seq Scan on layertype (cost=0.00..20.39 rows=655 width=110)"
> " Filter: (parentid = 300)"
The server thinks that every row of the table matches the WHERE clause.
That being the case, it's making the right choice to use a seqscan.
The question is why is the rows estimate so far off? Have you ANALYZEd
the table lately?
regards, tom lane