Hi Thiemo,
On 07/01/2019 11:30, Thiemo Kellner wrote:
Hi HP
Thanks for your reply.
Quoting "Peter J. Holzer" <hjp-pgsql@hjp.at>:
On 2018-12-25 11:54:11 +0000, Thiemo Kellner wrote:
[three different but functionally equivalent queries]
Explain analyze verbose showed for:
A (cost=264.72..626.97 rows=31 width=90) (actual time=1.117..1.117 rows=0
loops=1)
C (cost=0.42..611.19 rows=31 width=52) (actual time=2.217..2.217 rows=0
loops=1)
626.97 doesn't seem "much higher" to me than 611.19. I would call that
"about the same".
So would I but the cost is given as a range. Taking the the average somewhat 400 compare to somewhat 300. I do not know whether averaging is appropriate here.
The cost is not a range. The 2 numbers you see are:
As you can read here:
https://www.postgresql.org/docs/current/using-explain.html
regards,
fabio pardi