几十万的数据更新总是超时

update shop_snsn
set nclassid = '172'
where  (IsNumeric(nclassid) = 0) AND (shopclass = '2') AND (adddate > '2009-04-07')

更新如此简单的，在sql2000中总是超时。。。请高手帮忙。。。

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select *
into #temp
from shop_snsn
WHERE (IsNumeric(nclassid) = 0) AND (shopclass = '2') AND (adddate > '2009-04-07')

update shop_snsn
SET nclassid = '172'
from shop_snsn a,#temp b
where a.聚集索引列=b.聚集索引列