Wednesday, March 5, 2014
On Wednesday, March 5, 2014 12:32:04 AM UTC, John Merlino wrote:
reports = Report.find_by_sql(["SELECT DISTINCT ON (unit_id) r.*FROM reports rWHERE r.unit_id IN (?)ORDER BY unit_id, time DESC",units.map(&:id)])But this is running incredibly slow. In fact, after 15 minutes, I just cancelled the process.Any idea why the second query is taking markedly longer than the first?
Run the query through explain (depending on your rails version, that might get logged for you automatically) and see what your database is doing.
Fred
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