| From: | Andrey Lepikhov <a(dot)lepikhov(at)postgrespro(dot)ru> |
|---|---|
| To: | Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Justin Pryzby <pryzby(at)telsasoft(dot)com> |
| Cc: | Peter Geoghegan <pg(at)bowt(dot)ie>, Robert Haas <robertmhaas(at)gmail(dot)com>, Greg Stark <stark(at)mit(dot)edu>, vignesh C <vignesh21(at)gmail(dot)com>, Ibrar Ahmed <ibrar(dot)ahmad(at)gmail(dot)com>, "David G(dot) Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, Simon Riggs <simon(at)2ndquadrant(dot)com>, Ron Mayer <rm_pg(at)cheapcomplexdevices(dot)com>, Euler Taveira de Oliveira <euler(at)timbira(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Subject: | Re: explain analyze rows=%.0f |
| Date: | 2022-11-07 04:20:59 |
| Message-ID: | a9393107-6bb9-c835-50b7-c0f453a514b8@postgrespro.ru |
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| Lists: | pgsql-hackers |
On 22/7/2022 16:47, Amit Kapila wrote:
> I feel the discussion has slightly deviated which makes it unclear
> whether this patch is required or not?
After quick review I want to express my thoughts.
At first, We have been waiting for this feature for years. Often clients
give an explain to us where we see something like:
"rows=0, loops=1000000".
Without verbose mode, I can't even understand whether this node produces
any rows or not.
So, I think this feature is useful for parameterized plans mostly.
Also, printing two decimal digits or even three isn't meaningful -
sometimes we have a plan where number of loops is about 1E6 or even 1E7,
but number of real rows is equal 100 or 1000.
To overcome this issue, I see two options:
1. Show the exact number of tuples without division by loops (fair case
but invasive and bad for automation tools).
2. Show rows in scientific format like X.XXEXX.
I vote for second option.
--
regards,
Andrey Lepikhov
Postgres Professional
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