Always test your performance assumptions. The plpgsql function is
faster than the sql function, a lot faster on smaller arrays.
unnest - 10 element array - 100,000 times: 6701.746 ms
unnest - 100 element array - 100,000 times: 11847.933 ms
unnest - 1000 element array - 100,000 times: 59472.691 ms
explode - 10 element array - 100,000 times: 1941.942 ms
explode - 100 element array - 100,000 times: 8521.289 ms
explode - 1000 element array - 100,000 times: 44980.048 ms
On 29/05/2009, at 8:55 PM, Grzegorz Jaśkiewicz wrote:
why complicate so much ? this is a single sql query. It really shocks
me, how people easily lean on plpgsql and for/loops - which are times
slower than simple sql query:
CREATE FUNCTION unnest(anyarray) RETURNS SETOF anyelement AS
$_$
SELECT ($1)[i] FROM
generate_series(array_lower($1,1),array_upper($1,1)) i;
$_$
LANGUAGE sql IMMUTABLE;
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