Re: Manipulating complex types as non-contiguous structures in-memory
| От | Pavel Stehule |
|---|---|
| Тема | Re: Manipulating complex types as non-contiguous structures in-memory |
| Дата | |
| Msg-id | CAFj8pRB-otCuSW4JMMAddwaEk9RnYuKjorjLdLtQM=QwzAs4mA@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Manipulating complex types as non-contiguous structures in-memory (Pavel Stehule <pavel.stehule@gmail.com>) |
| Ответы |
Re: Manipulating complex types as non-contiguous structures in-memory
|
| Список | pgsql-hackers |
2015-05-01 20:53 GMT+02:00 Pavel Stehule <pavel.stehule@gmail.com>:
Original Patch
2015-05-01 20:11 GMT+02:00 Tom Lane <tgl@sss.pgh.pa.us>:Pavel Stehule <pavel.stehule@gmail.com> writes:
> I am looking on this patch, but it cannot be applied now.
> lxml2 -lssl -lcrypto -lrt -lcrypt -ldl -lm -o postgres
> utils/fmgrtab.o:(.rodata+0x2678): undefined reference to `array_append'
> utils/fmgrtab.o:(.rodata+0x2698): undefined reference to `array_prepend'
What are you trying to apply it to? I see array_append() in
src/backend/utils/adt/array_userfuncs.c in HEAD. Also, are
you checking the 1.1 version of the patch?I tested old version. 1.1. looks well.
It is hard to believe how it is fast
I use buble sort for plpgsql benchmarking. Following variant is suboptimal (but it is perfect for this test)
CREATE OR REPLACE FUNCTION public.buble(a anyarray, OUT r anyarray)
RETURNS anyarray
LANGUAGE plpgsql
AS $function$
DECLARE
aux r%type;
sorted bool := false;
BEGIN
r := a;
WHILE NOT sorted
LOOP
sorted := true;
FOR i IN array_lower(a,1) .. array_upper(a,1) - 1
LOOP
IF r[i] > r[i+1] THEN
sorted := false;
aux[1] := r[i];
r[i] := r[i+1]; r[i+1] := aux[1];
END IF;
END LOOP;
END LOOP;
END;
$function$
CREATE OR REPLACE FUNCTION public.array_generator(integer, anyelement, OUT r anyarray)
RETURNS anyarray
LANGUAGE plpgsql
AS $function$
BEGIN
r := (SELECT ARRAY(SELECT random()*$2 FROM generate_series(1,$1)));
END;
$function$
CREATE OR REPLACE FUNCTION public.buble(a anyarray, OUT r anyarray)
RETURNS anyarray
LANGUAGE plpgsql
AS $function$
DECLARE
aux r%type;
sorted bool := false;
BEGIN
r := a;
WHILE NOT sorted
LOOP
sorted := true;
FOR i IN array_lower(a,1) .. array_upper(a,1) - 1
LOOP
IF r[i] > r[i+1] THEN
sorted := false;
aux[1] := r[i];
r[i] := r[i+1]; r[i+1] := aux[1];
END IF;
END LOOP;
END LOOP;
END;
$function$
CREATE OR REPLACE FUNCTION public.array_generator(integer, anyelement, OUT r anyarray)
RETURNS anyarray
LANGUAGE plpgsql
AS $function$
BEGIN
r := (SELECT ARRAY(SELECT random()*$2 FROM generate_series(1,$1)));
END;
$function$
Test for 3000 elements:
Integer 55sec 8sec
Numeric 341sec 8sec
Quicksort is about 3x faster -- so a benefit of this patch is clear.
Regards
Pavel
RegardsPavel
regards, tom lane
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