The original motivation for this commit was that shared_ptr_helper used
std::shared_ptr<>() which does two heap allocations instead of
make_shared<>() which does a single allocation. Turned out that
1. the affected code (--> Storages/) is not on a hot path (rendering the
performance argument moot ...)
2. yet copying Storage objects is potentially dangerous and was
previously allowed.
Hence, this change
- removes shared_ptr_helper and as a result all inherited create() methods,
- instead, Storage objects are now created using make_shared<>() by the
caller (for that to work, many constructors had to be made public), and
- all Storage classes were marked as noncopyable using boost::noncopyable.
In sum, we are (likely) not making things faster but the code becomes
cleaner and harder to misuse.
1. Dropped support for DatabaseOrdinary for MaterializeMySQL. It
is marked as experimental, and dropping support makes the code
more maintaible, and speeds up integration tests by 50%.
2. Get rid of thread name logic for StorageMaterializeMySQL wrapping,
use setInternalQuery instead (similar to MaterializedPostgreSQL).
