On Thu, Nov 8, 2012 at 05:37:22PM -0800, Tianyin Xu wrote:
> Thanks, Craig,
>
> Yes, I know "context diff". What I don't know is whether + or - some rows is a
> big problem, let's say correctness problem. I didn't write the test cases so I
> don't know what these test cases are exactly doing.
> If you tell me the failure of these test cases are severe and not acceptable,
> I'm fine with it. It means these configurations are not allowed.
>
> For this particular case, I figured out that it's because of the following
> settings,
>
> cpu_index_tuple_cost = 2147483647
>
> which assigned a big number to the cpu_index_tuple_cost, affecting the query
> planner.
>
> But to me, the configuration settings should not affect the correctness, right?
> Because whatever optimizations you do, the results should be the same (what
> matters is the performance). And that's why I need testing before adjusting
> these values.
We can't test the optimizer is reasonable if you change settings in this
way, so no, I am not surprised it failed.
--
Bruce Momjian <bruce@momjian.us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ It's impossible for everything to be true. +