This is yet another part in the BTI index project.
Overarching issue: https://github.com/scylladb/scylladb/issues/19191
Previous part: https://github.com/scylladb/scylladb/pull/25506/
Next part: plugging the BTI index readers and writers into sstable readers and writers.
The new code added in this PR isn't used outside of tests yet, but it's posted as a separate PR for reviewability.
This series implements, on top of the key translation logic, and abstract trie writing and traversal logic, a writer and a reader of sstable index files (which map primary keys to positions in Data.db), as described in f16fb6765b/src/java/org/apache/cassandra/io/sstable/format/bti/BtiFormat.md.
Caveats:
1. I think the added test has reasonable coverage, but that depends on running it multiple times. (Though it shouldn't need more than a few runs to catch any bug it covers). It's somewhat awkward as a test meant for running in CI, it's better as something you run many times after a relevant change.
2. These readers and writers are intended to be compatible with Cassandra, but I did *NOT* do any compatibility testing. The writers and readers added here have only been tested against each other, not against Cassandra's readers and writers.
3. This didn't undergo any proper benchmarking and optimization work. I was doing some measurements in the past, but everything was rewritten so much since then that the my old measurements are effectively invalidated. Frankly I have no idea what the performance of all this branchy-branchy logic is now.
No backports needed, new functionality.
Closesscylladb/scylladb#25626
* github.com:scylladb/scylladb:
test/manual: add bti_cassandra_compatibility_test
test/lib/random_schema: add some constraints for generated uuid and time/date values
test/lib/random_utils: add a variant of get_bytes which takes an `engine&`
test/boost: add bti_index_test
sstables/writer: add an accessor for the current write position in Data.db
sstables/trie: introduce bti_index_reader
sstables/trie: add bti_partition_index_writer.cc
sstables/trie: add bti_row_index_writer.cc
utils/bit_cast: add a new overload of write_unaligned()
sstables/trie: add trie_writer::add_partial()
sstables/consumer: add read_56()
sstables/trie: make bti_node_reader::page_ptr copy-constructible
sstables: extract abstract_index_reader from index_reader.hh to its own header
sstables/trie: add an accessor to the file_writer under bti_node_sink
sstables/types: make `deletion_time::operator tombstone()` const
sstables/types: add sstables::deletion_time::make_live()
sstables/trie: fix a special case in max_offset_from_child
sstables/trie: handle `partition_region`s other than `clustered` in BTI position encoding
sstables/trie: rewrite lcb_mismatch to handle fragment invalidation
test/boost/bti_key_translation_test: fix a compilation error hidden behind `if constexpr`
fc64333040