© 2004
Canonical Ltd.
•
Terms of use
•
Data privacy
•
Contact Launchpad Support
•
Blog
•
Careers
•
System status
•
0e1f616
(Get the code!)
EXPLAIN is fast—definitely sub-second even in tragically difficult cases; I doubt we'll ever spend more than 20 milliseconds on one.
It's EXPLAIN ANALYZE that's slow. But we shouldn't do that anyway because it executes the query in order to get the timings.
The practical use of this feature isn't clear until we try it. Right now we often face the question: "it runs fine for me now, and the plan looks good... did the plan change or did something else happen?" We may find that the plan is always the same, in which case we can stop worrying about it—and the devs can be confident that they get representative oopses that they can use for optimization. Conversely we may find that the plans change, in which case we can stop agonizing over the exact plans and start worrying about avoiding unpredictability.