* refactor: change level 1 to level 2 preparing for next design changes
* fix: make level-2 consistent everywhere
* chore: remove unused comments
* refactor: change all the name level_1 to level_2 to completely replace 1 with 2 to amke everything consistent
* chore: add correspinding constants for the comapction levels in the comments
Co-authored-by: Dom <dom@itsallbroken.com>
* refactor: store per-file column set in catalog
Together with the table-wide schema and the partition-wide sort key, this should
be everything we need to read a parquet file directly into memory
without peeking any file-level metadata.
The querier will use this to directly load parquet files into the read
buffer.
**WARNING: This requires a catalog wipe!**
Ref #4124.
* refactor: use proper `ColumnSet` type
This commit changes the code base to use a new reference-counted
PartitionKey type wrapper, instead of passing a bare String around.
This allows the compiler to type check & verify usage of the partition
key, instead of passing a bare string around. By reference counting the
underlying string, we reduce memory usage for some use cases.
Carol (Nichols || Goulding)
Marco Neumann
Raphael Taylor-Davies
Nga Tran
Andrew Lamb
Dom Dwyer