Обсуждение: EXPLAIN

 When I do an explain what does the cost, size and width mean that is returned?

 Seq Scan on apts  (cost=249.95 size=2362 width=468)

 Thanks

 Andy

>  When I do an explain what does the cost, size and width mean that is returned?
>
>  Seq Scan on apts  (cost=249.95 size=2362 width=468)

Cost is a computed value by the optimizer of how long it will execute.
It is meaningful only in comparison to there queries.  size if the
number of rows estimated to return.  width is the number of bytes per
row returned.


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