* Add columns description to metadata in case of schema inference
* Make better
* Remove unnecessary code
* Fix tests
* More tests
* Add tag no-fasttest
* Fix test
* Fix test
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
TODO (suggested by Nikolai)
1. Build query plan fro current query (inside storage::read) up to WithMergableState
2. Check, that plan is simple enough: Aggregating - Expression - Filter - ReadFromStorage (or simplier)
3. Check, that filter is the same as filter in projection, and also expression calculates the same aggregation keys as in projection
4. Return WithMergableState if projection applies
3 will be easier to do with ActionsDAG, cause it sees all functions, and dependencies are direct (but it is possible with ExpressionActions also)
Also need to figure out how prewhere works for projections, and
row_filter_policies.
wip
