On 16/01/15 16:06, Mark Kirkwood wrote:
> A bit more poking about shows that the major factor (which this fake
> dataset anyway) is the default for effective_cache_size (changes from
> 128MB to 4GB in 9.4). Increasing this makes 9.2 start using the
> files_in_flight index in a plain index scan too.
>
Arrg - misread the planner output....in 9.2 what changes is a plan that
uses an index scan on the *file_state* index (not
files_in_flight)...which appears much faster than the bitmap scan on
file_state. Apologies for the confusion.
I'm thinking that I'm seeing the effect Tom has just mentioned.
regards
Mark