Re: Strange choice of general index over partial index

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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




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