* feat: parquet cache metrics
* feat: track parquet cache metrics
Adds metrics to track the following in the in-memory parquet cache:
* cache size in bytes (also included a fix in the calculation of that)
* cache size in n files
* cache hits
* cache misses
* cache misses while the oracle is fetching a file
A test was added to check this functionality
* refactor: clean up logic and fix cache removal tracking error
Some logic and naming was cleaned up and the boolean to optionally track
metrics on entry removal was removed, as it was incorrect in the first place:
a fetching entry still has a size, which counts toward the size of the
cache. So, this makes is such that anytime an entry is removed, whether
its state is success or fetching, its size will be decremented from
the cache size metrics.
The sizing caclulations were made to be correct, and the cache metrics
test was updated with more thurough assertions
Moved all of the last cache implementation into the `influxdb3_cache`
crate. This also splits out the implementation into three modules:
- `cache.rs`: the core cache implementation
- `provider.rs`: the cache provider used by the database to hold multiple
caches.
- `table_function.rs`: same as before, holds the DataFusion impls
Tests were preserved and moved to `mod.rs`, however, they were updated to
not rely on the WriteBuffer implementation, and instead use the types in
the `influxdb3_cache::last_cache` module directly. This simplified the
test code, while not changing any of the test assertions at all.
This adds the MetaDataCacheProvider for managing metadata caches in the
influxdb3 instance. This includes APIs to create caches through the WAL
as well as from a catalog on initialization, to write data into the
managed caches, and to query data out of them.
The query side is fairly involved, relying on Datafusion's TableFunctionImpl
and TableProvider traits to make querying the cache using a user-defined
table function (UDTF) possible.
The predicate code was modified to only support two kinds of predicates:
IN and NOT IN, which simplifies the code, and maps nicely with the DataFusion
LiteralGuarantee which we leverage to derive the predicates from the
incoming queries.
A custom ExecutionPlan implementation was added specifically for the
metadata cache that can report the predicates that are pushed down to
the cache during query planning/execution.
A big set of tests was added to to check that queries are working, and
that predicates are being pushed down properly.
* feat: core metadata cache structs with basic tests
Implement the base MetaCache type that holds the hierarchical structure
of the metadata cache providing methods to create and push rows from the
WAL into the cache.
Added a prune method as well as a method for gathering record batches
from a meta cache. A test was added to check the latter for various
predicates and that the former works, though, pruning shows that we need
to modify how record batches are produced such that expired entries are
not emitted.
* refactor: filter expired entries and do some clean up in the meta cache
Trevor Hilton