G
George Potemkin
Guest
> And, are we sure that the WHERE FALSE is really doing all the same DB work? I'm sure. Checked with promon. > My point is just that WHERE FALSE is not a real world example because it provides no index selection and yet reads every record. The query uses exactly the same index as with WHERE TRUE clause (or without an explict WHERE clause) - the primary index. A bit off-topic: comparing a standard readprobe test vs. its "aggressive" version (with WHERE FALSE clause) is useful for a proving that the current bottleneck is the latches rather than the lack of CPUs on the box. Only if both tests shows the best results on the same number of concurrent sessions then the bottleneck is the latches.
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