Re: Does PLPythonU support COPY table FROM string?

On 08/28/2015 08:32 AM, Dominik Czarnota wrote:
> I am launching it from postgres plpythonu function (postgres version:
> PostgreSQL 9.4.4 on x86_64-unknown-linux-gnu, compiled by gcc (Debian
> 4.9.2-10) 4.9.2, 64-bit).
>
> The error can be reproduced using the SQL below:
>
> DROP TABLE IF EXISTS test;
> CREATE TABLE test(field1 integer, field2 integer);
>
> CREATE OR REPLACE FUNCTION example() RETURNS VOID AS
> $$
> plpy.execute("COPY test (field1, field2) FROM STDIN
> DELIMITER',';\n1,2\n\\.")
> $$ LANGUAGE 'plpythonu';
>
> select example();
>
>
> Maybe there is a way to get into the underlying psycopg2 driver and call
> some method that would do COPY FROM, but I can't find anything related
> to it in the docs.

The only thing I can think of is using io.BytesIO() to create an in
memory file and then reading from that. I have done it using psycopg2,
but not in plpythonu so I would mark this untested.

Otherwise, could you explain more where the list is coming from and it's
size as there may be other ways to attack this.

>
> 2015-08-28 17:15 GMT+02:00 Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com
> <mailto:adrian(dot)klaver(at)aklaver(dot)com>>:
>
> On 08/28/2015 05:58 AM, Dominik Czarnota wrote:
>
> Hello,
>
> Is there any possibility to make COPY from list of records in
> PLPythonU?
>
> I've tried to simply call `plpy.execute(query)` with such query:
>
> COPY table (field1, field2, field3) FROM STDIN DELIMITER',';
> val1,val2,val3
> \.
>
> But it fails with not so explicit error:
> ProgrammingError: (psycopg2.ProgrammingError)
> spiexceptions.SyntaxError:
> syntax error at or near "val1"
> LINE 2: val1,val2,val3
> ^
>
>
> The above is a psycopg2 error, so where are you running this and how?
>
>
>
> However the same thing works in psql.
>
> After some googling I found out that it doesn't work inside sql
> functions because there is no STDIN (
> http://www.postgresql.org/message-id/000501c5acc9$83747aa0$0501a8c0@plexus
> ).
>
>
> I've got working solution which was saving tmp file and then calling
> `COPY table FROM 'path'` but that's not cool.
>
> Did I miss something in plpythonu api? If not, where can I post
> "feature
> request" for that?
> Or can you point me place where I could dig into the code and
> implement it?
>
>
> ----
> Dominik Czarnota
>
>
>
> --
> Adrian Klaver
> adrian(dot)klaver(at)aklaver(dot)com <mailto:adrian(dot)klaver(at)aklaver(dot)com>
>
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com