"In production this query was taking too long, so the next step was to look at the query plan, which showed a table scan was being used instead of an index. A new index was created which cut the page load time by a factor of 10."
I read it as: 1) noticed that's slow in production, 2) look at query plan (prod or dev, not clear) 3) add index (not clear if they did that in dev first and then prod)
my dev box runs a clone of production, I do all my tuning on dev then deploy to staging, confirm it is still good there and finally ship it to production
I read it as: 1) noticed that's slow in production, 2) look at query plan (prod or dev, not clear) 3) add index (not clear if they did that in dev first and then prod)