Changes:
* LeafNode is aligned to LEAF_PAGE_SIZE.
Alignment brings 24 bytes memory overhead for 4096, but reduces
cache misses rate.
* Unused m_element_count from leaf nodes file.
The size is computed as m_leaves_region.size() / LEAF_PAGE_SIZE.
* Added try/catch for mmap exceptions messages.
candidate_cache is removed because of failing test
make util-tests && ./unit_tests/util-tests --run_test=*/construct_multiple_levels_test
first bad commit: [9692be6f50] Add cache for CandidateSegments to reduce heap worke even more
Now SegmentIndex contains leaf index, object index and fixed_projected_coordinate
This increses query performance dramatically for queries with a lot of
coordinates. However it increases the internal memory usage of the
StaticRTree also 4x.
StaticRTree now uses projected coordinates internally. That means we can
use a euclidean distance measure (squared distance) for sorting the
query queue.
Small fixes I didn't want to include in unrelated PRs.
There are a few left in `storage.cpp` but since it's a single function
in 600 lines of code, I didn't want to touch the mess. The others are
safe to remove, cucumber and test run on Finland gives 👍.
rather than being cached in the StaticRTree. This means we
can freely apply traffic data and not have stale values lying
around. It reduces the size of the RTree on disk, at the expense
of some additional data in RAM.
Phew, a lot of classes were affected by this. The rationale for the
changes are as follows:
- When a type X declares any constructor, the default constructor is
not declared, so there is no need for X() = delete there. In fact,
there is brutal difference between those two: deleted members
participate in overload resolution, but not-declared members do not!
- When a type X wants to be non-copyable (e.g. to be only movable, like
threads, unique_ptrs, and so on), you can either do it by inheriting
from boost::noncopyable (the old way), or better declare both (!) the
copy constructor _and_ the copy assignment operator as deleted:
X(X const&) = delete;
X& operator=(X const&) = delete;
We had tons of types with deleted copy constructors that were lacking
a corresponding deleted copy assignment operator, making them still
copyable and you wouldn't even notice (read: scary)!
References:
- http://accu.org/content/conf2014/Howard_Hinnant_Accu_2014.pdf
- http://www.boost.org/doc/libs/master/libs/core/doc/html/core/noncopyable.html
Note: I know, I'm quoting Hinnant's extraordinary slides a lot, but
getting the sematic right here is so incredibly important.
