On Thu, 20 May 2021 11:45:22 +0000, Omacht András <omacht.and...@libra.hu>
wrote:
> UDF has been a compromise for us from the beginning (since IB 6.0 or maybe
> 5.5). If it is possible, we don’t want to depend on things outside of the
> database because it is only a problem to have to ask the customers for any
> extras for the programs to work.
>
At same time UDF is still faster than UDR/function. I did some
testing with Firebird 3.0.7 ja 4.0.0RC1. I have UDF with three
functions, one of which can be rewritten as PSQL function. Results, when
used in where condition were:
UDF: ~10 sec
UDR/PSQL Function: ~15 sec (UDR and PSQL function had no practical speed
difference).
PSQL SP: ~19 sec
For the other two functions it would be nice, if Firebrid 4.0
could do timezone conversion for TIMESTAMP WITHOUT TIMEZONE type.
Existing database has some fields, that contain timestamps in UTC time,
but some querys require converting it to local timezone (and some
reverse). And since developement enviroment does not have data type for
time wiht timezone, converting to TIMESTAMP WITH TIMEZONE is not
possible.
Actually, one conversion could be done with:
CAST((CAST(FIELD_WITH_UTC_TIME||'UTC' AS TIMESTAMP WITH TIME ZONE) AT LOCAL) AS
TIMESTAMP)
But it is ~4.5 times slower than UDF.
--
Virgo Pärna
virgo.pa...@mail.ee
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