Do you have an index on uptime_id (I suspect not, since your analyze output doesn't show it being used)? The subquery shouldn't be all that bad, unless there's no index. The main query should use a sequential scan, but the sub-query should be using an index, if it's a decent query optimizer. I agree the joined query is better anyway, and without an index, it's at least able to use a merge join, but that's still worse than if it could use an index for the join.

In reply to Re^2: OT: peak values with SQL by runrig
in thread OT: peak values with SQL by revdiablo

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