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174b101a49
The row_cache::partitions_type is replaced from boost::intrusive::set to bplus::tree<Key = int64_t, T = array_trusted_bounds<cache_entry>> Where token is used to quickly locate the partition by its token and the internal array -- to resolve hashing conflicts. Summary of changes in cache_entry: - compare's goes away as the new collection needs tri-compare one which is provided by ring_position_comparator - when initialized the dummy entry is added with "after_all_keys" kind, not "before_all_keys" as it was by default. This is to make tree entries sorted by token - insertion and removing of cache_entries happens inside double_decker, most of the changes in row_cache.cc are about passing constructor args from current_allocator.construct into double_decker.empace_before() - the _flags is extended to keep array head/tail bits. There's a room for it, sizeof(cache_entry) remains unchanged The rest fits smothly into the double_decker API. Also, as was told in the previous patch, insertion and removal _may_ invalidate iterators, but may leave them intact. However, currently this doesn't seem to be a problem as the cache_tracker ::insert() and ::on_partition_erase do invalidate iterators unconditionally. Later this can be otimized, as iterators are invalidated by double-decker only in case of hash conflict, otherwise it doesn't change arrays and B+ tree doesn't invalidate its. tests: unit(dev), perf(dev) Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>