crawler

ebay.sql

CREATE OR REPLACE FUNCTION new_peer(n character varying, r bigint, c bigint, tp integer, lp integer)
  RETURNS bigint AS
$BODY$
DECLARE peerid bigint;
BEGIN
    LOOP
        -- first try to update the key
        UPDATE peers INTO peerid SET lastpage=lp WHERE "name" = n returning id;
        IF found THEN
      -- SELECT id into peerid from peers where "name"=n;
            RETURN peerid;
        END IF;
        -- not there, so try to insert the key
        -- if someone else inserts the same key concurrently,
        -- we could get a unique-key failure
        BEGIN
            INSERT INTO peers("name", "reputation", "capital", "totalpages", "lastpage") values(n, r, 0, tp, lp);
        EXCEPTION WHEN unique_violation THEN
            -- do nothing, and loop to try the UPDATE again
        END;
    END LOOP;
END;
$BODY$
  LANGUAGE plpgsql VOLATILE