Justin wrote:
> Then why are the estimates so far off?
Perhaps a really high correlation between those records where coitem_status = 'O' and those records in your date range.
Theplanner estimates 1 row when restricting by both restrictions, whereas there where 458. The 1 row was probably a
resultof a small % for status='O' multiplied by a small % for the date range.
> If estimates where correct would it improve the performance that much.
Possibly, but a better performance gain might be obtained by rewriting the query, changing the case expression to
somethingalong the lines of:
coalesce((select wrkcnt_code || ' Operation Completed :' || cast(wooper_seqnumber as text) from wooper inner join
wrkcnton wrkcnt_id = wooper_wrkcnt_idwhere wooper_rncomplete = true and wooper_wo_id = coitem_order_idorder by
wooper_seqnumberdesc limit 1
),'No Operation Completed') as LastFinshedOp
regards,
Stephen Denne.
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