Livius,
thank you.

And:  cool!  You obviously have hit *something*.
I learned before on different groups and seminars, that when comparing
different  execution times you better start by looking at the plans...
only... I usually don't :-)

So,  the  question needs to be changed from:
"Was there such a change between subreleases"

to:
"what have I done or omitted - unknowingly - to get different plans?"

I  don't  manipulate  query  plans, in fact I never touch them, or any
settings   related   to   them  because  in my case surely the risk of
breaking more than I would be fixing is substantial :-)

But  now  when  I look at them, they are different on the fast vs. the
slow machines!!!

Here is what I get for the query:

fast execution:
PLAN  JOIN  (JOIN (I INDEX (PI_T_INVOICES), R2 INDEX (I_T_RESULTS)), K
INDEX (I_T_KEYS)
PLAN (R1 NATURAL)

slow execution:
PLAN  MERGE  (SORT  (JOIN  (I  NATURAL, K INDEX (I_T_KEYS))), SORT (R2
INDEX (I_T_RESULTS)))
PLAN (R1 NATURAL)

Query   and   database   are  identical,  both  created  from the same
backup.

But  I  have an idea which I will check later this afternoon. It's all
probably just something on 2 or 3 of my systems.

I'll report back!

thanks,
André

> 


> Probably difference in query plans.
> Show query plan for both server versions




> Regards,Karol Bieniaszewski
> -------- Oryginalna wiadomość --------
> Od: "André Knappstein Knappstein@...
> [firebird-support]" <firebird-support@yahoogroups.com>
> Data: 12.11.2018  12:01  (GMT+01:00)
> Do: firebird-support@yahoogroups.com
> Temat: [firebird-support] Speed difference 2.5.3 - 2.5.7

>   Hello all,
> 
> for  a  local  conference,  I    am    preparing   a   session   for a
> Firebird  beginners'  group,  to  demonstrate  the  basics  of  Stored
> Procedures and their usage from different clients.
> 
> One scenario is about transforming a *slightly* complex sql query into
> a selectable stored proc which will yield the same result.
> 
> I stumbled over something strange:
> Query  and  SP  are  running with similar same speed on 2.5.7, which I
> have   in  production  systems. But query is *MUCH* slower than stored
> proc  on  different(!)  2.5.3  systems  (more  rarely used machines, I
> failed to upgrade so far).
> 
> 2.5.7. systems: ~ 3 seconds for Query and SP
> 2.5.3. systems: ~ 3 seconds for SP, 15 minutes(!) for Query
> always  tested  from  a  fresh restored database with starting results
> normalized to 0,00.
> 
> It  does  not look like a difference in the machines' hardware or even
> the used antivirus or OS can cause this big a difference.
> 
> Just  out   of   curiosity  - because all production systems should be
> updated  to  at  least  2.5.7  anyway:   has   there   been   such  an
> improvement between sub releases?
> 
> I checked the change logs:
> https://www.firebirdsql.org/file/documentation/release_notes/Firebird-2.5..8-ReleaseNotes.pdf
> and  checked  all  between  2.5.3  and  2.5.8,  but found nothing that
> matches this experience.
> 
> Query  is  pretty  much straigthforward; one nested subquery to update
> outer stream, no UDF or other built-in functions
> 
> best regards,
> André
> 
> 


>   



------------------------------------
Posted by: =?utf-8?Q?Andr=C3=A9_Knappstein?= <Knappstein@...>
------------------------------------

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