Kevin Brown wrote:
Hints are dangerous, and I consider them a last resort.
If you consider them a last resort, then why do you consider them to
be a better alternative than a workaround such as turning off
enable_seqscan, when all the other tradeoffs are considered?
If I understand enable_seqscan, it's an all-or-nothing affair. Turning it off turns it off for the whole database, right? The same is true of all of the planner-tuning parameters in the postgres conf file. Since the optimizer does a good job most of the time, I'd hate to change a global setting like this -- what else would be affected? I could try this, but it would make me nervous to alter the whole system to fix one particular query.
If your argument is that planner hints would give you finer grained
control, then the question is whether you'd rather the developers
spend their time implementing planner hints or improving the planner.
I agree 100% -- I'd much prefer a better planner. But when it comes down to a do-or-die situation, you need a hack, some sort of workaround, to get you working *today*.
Regards,
Craig
