result_set_row is a heavyweight object containing multiple cell types:
regular columns, partition keys, and static values. To prevent expensive
accidental copies, delete the copy constructor and replace it with:
1. A move constructor for efficient vector reallocation
2. An explicit copy() method when copies are actually needed
This change reduces overhead in some non-hot paths by eliminating implicit
deep copies. Please note, previously, in `create_view_from_mutation()`,
we kept a copy of `result_set_row`, and then reused `table_rs` for
holding the mutation for `scylla_tables`. Because we don't copy
the `result_set_row` in this change, in order to avoid invalidating
the `row` after reusing `table_rs` in the outer scope, we define a
new `table_rs` shadowing the one in the out scope.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#22741
aa8c27b872