jd@commandprompt.com ("Joshua D. Drake") writes:
> On the other hand ANALYZE also:
>
> 1. Uses lots of memory
> 2. Lots of processor
> 3. Can take a long time
>
> We normally don't notice because most sets won't incur a penalty. We got a
> customer who
> has a single table that is over 1TB in size... We notice. Granted that is
> the extreme
> but it would only take a quarter of that size (which is common) to start
> seeing issues.
I find it curious that ANALYZE *would* take a long time to run.
After all, its sampling strategy means that, barring having SET
STATISTICS to some ghastly high number, it shouldn't need to do
materially more work to analyze a 1TB table than is required to analyze
a 1GB table.
With the out-of-the-box (which may have changed without my notice ;-))
default of 10 bars in the histogram, it should search for 30K rows,
which, while not "free," doesn't get enormously more expensive as tables
grow.
--
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Rules of the Evil Overlord #179. "I will not outsource core
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