Re: batch insertion

On Sat, Aug 24, 2013 at 7:15 PM, Korisk <korisk@yandex.ru> wrote:
> Hi!
> I want quick insert into db a lot of data (in form of triplets). Data is formed dynamical so "COPY" is not suitable.
> I tried batch insert like this:
>
> insert into triplets values (1,1,1);
> insert into triplets values (1,1,1), (3,2,5), (4,5,5);
> ...
> insert into triplets values (1,1,1), (3,2,5), (4,5,5) .... ;
>
> The more triplets I use the quicker operation is.
> With preparation it looks like this:
>
> res = PQprepare(conn, "qu", "insert into triplets values ($1::bigint, $2::bigint, $3::float);",3, NULL);
> ...
> res = PQprepare(conn, "qu", "insert into triplets values ($1::bigint, $2::bigint, $3::float), ($4::bigint,
$5::bigint,$6::float), ($7::bigint, $8::bigint, $9::float), ($10::bigint, $11::bigint, $12::float);",12, NULL); 
> ...
>
> The question:
> Is there any way to prepare query with any number of triplets without casting such a long string?

yes.  you can use COPY with some tricks, or use arrays.

CREATE TYPE triplet_t AS (a bigint, b bigint, c bigint);

WITH data AS (SELECT UNNEST($1::triplet_t[]) INSERT INTO triplets
SELECT * FROM data;

Also see libpqtypes: http://libpqtypes.esilo.com/man3/pqt-composites.html

merlin