Hi,
The only solution I've found to get the same reliable result, but
without locking, is the dirty way (loops) :
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CREATE OR REPLACE FUNCTION seq_min(sequence_name varchar, minval
integer) RETURNS VOID AS $$
DECLARE
sequence_record RECORD;
BEGIN
-- Get the current sequence value :
FOR sequence_record IN EXECUTE 'SELECT last_value FROM ' ||
sequence_name LOOP
NULL;
END LOOP;
-- Loop to bring the sequence to (at least) minval :
WHILE sequence_record.last_value < minval LOOP
-- Increment by 1 the sequence (and get the new value) :
FOR sequence_record IN EXECUTE 'SELECT nextval(''' || sequence_name
|| ''') AS last_value' LOOP
NULL;
END LOOP;
END LOOP;
RETURN;
END;
$$ LANGUAGE plpgsql;
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It gives the result I expect (and it doesn't interfere with concurrent
uses of the sequence), but it is not very optimized !
So, if someone have a better idea, I'm still open !
Thank you,
Philippe Ferreira.