Adds a benchmark that exercises the router's partitioning DmlHandler
implementation against a set of three files (very small, small, medium)
with 4 different partitioning schemes:
* Single tag, which occurs in all rows
* Single tag, which does not occur in any row
* Default strftime formatter (YYYY-MM-DD)
* Long and complicated strftime formatter
This covers the entire partitioning overhead - building the formatters,
evaluating each row, grouping the values into per-partition buckets, and
returning to the caller, where it normally would be passed to the next
handler in the pipeline.
Note that only one template part is evaluated in each case - this
measures the overhead of each type of formatter. In reality, we'd expect
partitioning with custom schemes to utilise more than one part,
increasing the cost of partitioning proportionally. This is a
lower-bound measurement!
This removes the look-aside cache from the retention_validation
and schema_validation DML handlers, instead setting up the new
NamespaceCache decorator and using that to handle cache misses.
This commit introduces a new (composable) trait; a NamespaceResolver is
an abstraction responsible for taking a string namespace from a user
request, and mapping to it's catalog ID.
This allows the NamespaceId to be injected through the DmlHandler chain
in addition to the namespace name.
As part of this change, the NamespaceAutocreation layer was changed from
an implementator of the DmlHandler trait, to a NamespaceResolver as it
is a more appropriate abstraction for the functionality it provides.
This doesn't really need to be fallible but forces propagation of a ton
of error handling - no shards is always a sign of something being very
wrong, and can be caught in the caller if it's for some reason an
acceptable state / can be recovered from.
Went through and remove all lazy_static uses with once_cell (while waiting for the project to compile). There are still dependencies using lazy_static so it is still in the crate graph but at least there isn't an explicit dependency on it (and it is easier to update to `std::lazy::Lazy` once that is stable).
Dom Dwyer
Carol (Nichols || Goulding)
Fraser Savage
Andrew Lamb
Markus Westerlind