i have a table named test.
which occupy around 400m.
i run two query as the following:
select * from test order by a;
select /*+PARALLEL(test,3)*/ * from test order by a;
for no parallel one , if data is inside SGA, it will read from SGA, for parallel one, even if data is inside SGA, it still read from disk.
am i right?
the reason i am asking this is because
i run both query several times, each time
i run first one, i didn't notice much disk activity.
but when i run second one, i notice a lot of disk activity.
also , i notice that parallel one is actually SLOWER than the
one without parallel.
guru is on the way!!!!
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