Search optimization

[patelprateek]

i read in the documentation

Create Searcher Searcher accepts level parameter as the optimization level. You can set level as 0 or 1 or 2. The higher the level, the faster the searching, but it may cause unstable recall.

Can you please elaborate on what exactly this optimization level is doing ? what does 0, 1, 2 indicate , how they change/impact the search process , what kind of optimizaton is done in the optimize method

Any documents or desing pointers will help