Re: [HACKERS] Transform for pl/perl

[Pavel Stehule]

Hi

2017-10-24 14:27 GMT+02:00 Anthony Bykov :

> There are some moments I should mention:
> 1. {"1":1}::jsonb is transformed into HV {"1"=>"1"}, while
> ["1","2"]::jsonb is transformed into AV ["1", "2"]
>
> 2. If there is a numeric value appear in jsonb, it will be transformed
> to SVnv through string (Numeric->String->SV->SVnv). Not the best
> solution, but as far as I understand this is usual practise in
> postgresql to serialize Numerics and de-serialize them.
>
> 3. SVnv is transformed into jsonb through string
> (SVnv->String->Numeric).
>
> An example may also be helpful to understand extension. So, as an
> example, function "test" transforms incoming jsonb into perl,
> transforms it back into jsonb and returns it.
>
> create extension jsonb_plperl cascade;
>
> create or replace function test(val jsonb)
> returns jsonb
> transform for type jsonb
> language plperl
> as $$
> return $_[0];
> $$;
>
> select test('{"1":1,"example": null}'::jsonb);
>
>
I am looking to this patch:

1. the patch contains some artefacts - look the word "hstore"

2. I got lot of warnings


make[1]: Vstupuje se do adresáře
„/home/pavel/src/postgresql/contrib/jsonb_plperl“
gcc -Wall -Wmissing-prototypes -Wpointer-arith
-Wdeclaration-after-statement -Wendif-labels -Wmissing-format-attribute
-Wformat-security -fno-strict-aliasing -fwrapv -fexcess-precision=standard
-g -ggdb -Og -g3 -fno-omit-frame-pointer -fPIC -I../../src/pl/plperl -I.
-I. -I../../src/include  -D_GNU_SOURCE -I/usr/include/libxml2
-I/usr/lib64/perl5/CORE  -c -o jsonb_plperl.o jsonb_plperl.c
jsonb_plperl.c: In function ‘SV_FromJsonbValue’:
jsonb_plperl.c:83:9: warning: ‘result’ may be used uninitialized in this
function [-Wmaybe-uninitialized]
  return (result);
 ^
jsonb_plperl.c: In function ‘SV_FromJsonb’:
jsonb_plperl.c:95:10: warning: ‘object’ may be used uninitialized in this
function [-Wmaybe-uninitialized]
  HV *object;
  ^~
In file included from /usr/lib64/perl5/CORE/perl.h:5644:0,
 from ../../src/pl/plperl/plperl.h:52,
 from jsonb_plperl.c:17:
/usr/lib64/perl5/CORE/embed.h:404:19: warning: ‘value’ may be used
uninitialized in this function [-Wmaybe-uninitialized]
 #define newRV(a)  Perl_newRV(aTHX_ a)
   ^~
jsonb_plperl.c:101:10: note: ‘value’ was declared here
  SV *value;
  ^
gcc -Wall -Wmissing-prototypes -Wpointer-arith
-Wdeclaration-after-statement -Wendif-labels -Wmissing-format-attribute
-Wformat-security -fno-strict-aliasing -fwrapv -fexcess-precision=standard
-g -ggdb -Og -g3 -fno-omit-frame-pointer -fPIC -shared -o jsonb_plperl.so
jsonb_plperl.o  -L../../src/port -L../../src/common -Wl,--as-needed
-Wl,-rpath,'/usr/lib64/perl5/CORE',--enable-new-dtags   -Wl,-z,relro
-specs=/usr/lib/rpm/redhat/redhat-hardened-ld -fstack-protector-strong
-L/usr/local/lib  -L/usr/lib64/perl5/CORE -lperl -lpthread -lresolv -lnsl
-ldl -lm -lcrypt -lutil -lc
make[1]: Opouští se adresář
„/home/pavel/src/postgresql/contrib/jsonb_plperl“

[pavel@nemesis contrib]$ gcc --version
gcc (GCC) 7.2.1 20170915 (Red Hat 7.2.1-2)
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

3. regress tests passed

4. There are not any documentation - probably it should be part of PLPerl

5. The regress tests doesn't coverage other datatypes than numbers. I miss
boolean, binary, object, ... Maybe using data::dumper or some similar can
be interesting

Note - it is great extension, I am pleasured so transformations are used.

Regards

Pavel







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Re: [HACKERS] Transform for pl/perl

[Robert Haas]

On Tue, Oct 24, 2017 at 1:01 PM, anthony  wrote:
> Hello.
> Please, check out jsonb transform
> (https://www.postgresql.org/docs/9.5/static/sql-createtransform.html)
> for pl/perl language I've implemented.

Neat.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company


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Re: [HACKERS] Transform for pl/perl

[Anthony Bykov]

There are some moments I should mention:
1. {"1":1}::jsonb is transformed into HV {"1"=>"1"}, while
["1","2"]::jsonb is transformed into AV ["1", "2"]

2. If there is a numeric value appear in jsonb, it will be transformed
to SVnv through string (Numeric->String->SV->SVnv). Not the best
solution, but as far as I understand this is usual practise in
postgresql to serialize Numerics and de-serialize them.

3. SVnv is transformed into jsonb through string
(SVnv->String->Numeric).

An example may also be helpful to understand extension. So, as an
example, function "test" transforms incoming jsonb into perl,
transforms it back into jsonb and returns it.

create extension jsonb_plperl cascade;

create or replace function test(val jsonb)
returns jsonb
transform for type jsonb
language plperl
as $$
return $_[0];
$$;

select test('{"1":1,"example": null}'::jsonb);


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