This reverts commit b0643f8959, reversing
changes made to e8b0f8faa9.
The change forgot to update
sstables_manager::get_highest_supported_format(), which results in
/system/highest_supported_sstable_version still returning me, confusing
and breaking tests.
Fixes: scylladb/scylla-dtest#6435Closesscylladb/scylladb#27379
Trie-based indexes and older indexes have a difference in metrics,
and the test uses the metrics to check for bypass cache.
To choose the right metrics, it uses highest_supported_sstable_format,
which is inappropriate, because the sstable format chosen for writes
by Scylla might be different than highest_supported_sstable_format.
Use chosen_sstable_format instead.
The test looks at metrics to confirm whether queries
hit the row cache, the index cache or the disk,
depending on various settings.
BIG index readers use a two level, read-through index cache,
where the higher layer stores parsed "index pages"
of Index.db, while the lower layer is a cache of
raw 4kiB file pages of Index.db.
Therefore, if we want to count index cache hits,
the appropriate metric to check in this case is
`scylla_sstables_index_page_hits",
which counts hits in the higher layer.
This is done by the test.
However, BTI index readers don't have an equivalent of the higher cache
layer. Their cache only stores the raw 4 kiB pages, and the hits are
counted in `scylla_sstables_index_page_cache_hits`. (The same metric
is incremented by the lower layer of the BIG index cache).
Before this commit, the test would fail with `ms` sstables,
because their reads don't increment `scylla_sstables_index_page_hits`.
In this commit we adapt the test so that it instead checks
`scylla_sstables_index_page_cache_hits` for `ms` sstables.
Use universalasync library to make test.py async code compatible
with synchronous code of dtest/ccm
Also, copied unmodified error_example_test.py from dtest as an example.
Run the test in `dev` mode only.
