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keys, compound: switch from bytes_view to managed_bytes_view

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The keys classes (partition_key et al) already use managed_bytes,
but they assume the data is not fragmented and make liberal use
of that by casting to bytes_view. The view classes use bytes_view.

Change that to managed_bytes_view, and adjust return values
to managed_bytes/managed_bytes_view.

The callers are adjusted. In some places linearization (to_bytes())
is needed, but this isn't too bad as keys are always <= 64k and thus
will not be fragmented when out of LSA. We can remove this
linearization later.

The serialize_value() template is called from a long chain, and
can be reached with either bytes_view or managed_bytes_view.
Rather than trace and adjust all the callers, we patch it now
with constexpr if.

operator bytes_view (in keys) is converted to operator
managed_bytes_view, allowing callers to defer or avoid
linearization.
This commit is contained in:
Michał Chojnowski
2020-12-20 23:22:38 +01:00
parent a1a0839164
commit dbcf987231
14 changed files with 160 additions and 89 deletions
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11
db/view/view.cc
View File

@@ -406,7 +406,7 @@ row_marker view_updates::compute_row_marker(const clustering_row& base_row) cons
deletable_row& view_updates::get_view_row(const partition_key& base_key, const clustering_row& update) {
std::vector<bytes> linearized_values;
auto get_value = boost::adaptors::transformed([&, this] (const column_definition& cdef) -> bytes_view {
auto get_value = boost::adaptors::transformed([&, this] (const column_definition& cdef) -> managed_bytes_view {
auto* base_col = _base->get_column_definition(cdef.name());
if (!base_col) {
bytes_opt computed_value;
@@ -423,7 +423,7 @@ deletable_row& view_updates::get_view_row(const partition_key& base_key, const c
if (!computed_value) {
throw std::logic_error(format("No value computed for primary key column {}", cdef.name()));
}
return linearized_values.emplace_back(*computed_value);
return managed_bytes_view(linearized_values.emplace_back(*computed_value));
}
switch (base_col->kind) {
case column_kind::partition_key:
@@ -433,8 +433,13 @@ deletable_row& view_updates::get_view_row(const partition_key& base_key, const c
default:
auto& c = update.cells().cell_at(base_col->id);
auto value_view = base_col->is_atomic() ? c.as_atomic_cell(cdef).value() : c.as_collection_mutation().data;
// FIXME: don't linearize.
// This is hard right now, because we are dealing with two different types:
// managed_bytes_view and data::basic_value_view, and we can't put both types in one
// container.
// If IMR transitions to managed_bytes_view, this should be revisited.
if (value_view.is_fragmented()) {
return linearized_values.emplace_back(value_view.linearize());
return managed_bytes_view(linearized_values.emplace_back(value_view.linearize()));
}
return value_view.first_fragment();
}