Re: [MonetDB-users] Tweaking performance

Garrett Smith wrote:
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Does anyone have some guidance on approaches for optimizing database performance?
I realize this is a pretty broad question :)
More specifically, I'm running a simple query
select max(date) from metric
on a table with 21 million rows (or whatever you call them in Monet). It's taking quite a bit longer than I'd expect, given a typically indexed column. Given the fact that there is no (b-tree) index, the underlying engine has to perform a scan to find the maximum. This entails a linear scan over 21M elements in the current implementation.
On an "explain" I see that there's no difference between the plan with or without the presence of an index on 'date'. Per the SQL index docs, I see that indexes are more of a hint to Monet and they're often ignored.
Cool.
But what happens when I want to fix what seems to be a configuration problem with my database/schema?
Thanks!
Garrett
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Martin Kersten