An optimizer allegory

My attempt to give end users a feeling for SQL performance tuning:

Once upon a time there was a backwoodsman. His task was to clamber over the ridges and ford the streams between two settlements, not just once, but in every conceivable combination, in hopes of discovering the fastest route for the road-builders who were to follow. What a hard life! He sometimes overlooked a route. Or some stream that he thought he was done with would shift its course. And he was so tired!

Finally he exclaimed, "Oh, Evil One, I know you can hear me because the way I feel convinces me that I must not be far from your domain. If you would just make these roads find their own way through the wilderness by themselves, so that all a person had to do was say "Get me to Jamestown" and a road would appear, I would give anything. Anything!"

The Evil One appeared immediately, and handed him a contract and a red pen. "Sign here," he said, suppressing a grin. And as soon as the backwoodsman did, roads began to appear magically in front of every traveler through the wilderness.

He decided to try the new system. So he walked to the edge of town and said, "Get me to Jamestown." A smooth, finely-built road materialized and he began to follow it. Imagine his disappointment when, instead of following a valley trail he had blazed which went straight to Jamestown, it began switchbacking up a nearby ridge -- and not even heading in the right direction.

The backwoodsman asked the road, "Why are you going this way? There's a shortcut through the valley, under those trees!"

The road replied, "I overlooked that route. A stream must have shifted its course. And I am so tired!"

• Paul de Anguera, City of Seattle / HRIS