Changes the partitioning logic to be fallible. This prevents an invalid
partition template from causing a panic, previously possible through two
known code paths:
* TagValue formatter referencing a non-tag column
* Time formatter using an invalid strftime format string
If either occurs, the write attempt is now aborted and an error returned
to the user with a HTTP 500 status code.
Additionally unexpected partitioner errors now map to a catch-all error
instead of panicking.
Move the import into the submodule itself, rather than re-exporting it
at the crate level.
This will make it possible to link to the specific module/logic.
Min/max values and distinct counts are already optional, so let's make
the null counts optional as well. This will be helpful for NG to deal w/
partial statistics (e.g. we only populate stats for the time column).
Note that the total count is still mandatory, but we normally have the
chunk/file-level row count at hand.
Carol (Nichols || Goulding)
Dom Dwyer
Andrew Lamb
Marco Neumann
Andrew Lamb
Raphael Taylor-Davies