Files
scylladb/index/built_indexes_virtual_reader.hh
Avi Kivity 69a385fd9d Introduce schema/ module
Schema related files are moved there. This excludes schema files that
also interact with mutations, because the mutation module depends on
the schema. Those files will have to go into a separate module.

Closes #12858
2023-02-15 11:01:50 +02:00

239 lines
10 KiB
C++

/*
* Copyright (C) 2018-present ScyllaDB
*/
/*
* SPDX-License-Identifier: AGPL-3.0-or-later
*/
#include "replica/database.hh"
#include "db/system_keyspace.hh"
#include "readers/flat_mutation_reader_v2.hh"
#include "mutation/mutation_fragment_v2.hh"
#include "query-request.hh"
#include "schema/schema_fwd.hh"
#include "secondary_index_manager.hh"
#include "tracing/tracing.hh"
#include "view_info.hh"
#include <memory>
namespace db::index {
class built_indexes_virtual_reader {
replica::database& _db;
struct built_indexes_reader : flat_mutation_reader_v2::impl {
replica::database& _db;
schema_ptr _schema;
query::partition_slice _view_names_slice;
flat_mutation_reader_v2 _underlying;
sstring _current_keyspace;
// Convert a key holding an index name (e.g., xyz) to a key holding
// the backing materialized-view name (e.g., xyz_index).
static clustering_key_prefix index_name_to_view_name(
const clustering_key_prefix& c,
const schema& built_views_schema,
const schema& built_indexes_schema)
{
sstring index_name = value_cast<sstring>(utf8_type->deserialize(*c.begin(built_indexes_schema)));
sstring view_name = ::secondary_index::index_table_name(index_name);
return clustering_key_prefix::from_single_value(built_views_schema, utf8_type->decompose(view_name));
}
// Convert a clustering_range holding a range of index names (e.g.,
// abc..xyz) to a range of backing view names (abc_index..xyz_index).
static query::clustering_range index_name_range_to_view_name_range(
const query::clustering_range& range,
const schema& built_views_schema,
const schema& built_indexes_schema)
{
bool singular = range.is_singular();
auto start = range.start();
auto end = range.end();
if (start) {
*start = query::clustering_range::bound(
index_name_to_view_name(start->value(), built_views_schema, built_indexes_schema),
start->is_inclusive());
}
if (end) {
*end = query::clustering_range::bound(
index_name_to_view_name(end->value(), built_views_schema, built_indexes_schema),
end->is_inclusive());
}
return query::clustering_range(std::move(start), std::move(end), singular);
}
// The index list reader is created with a slice of index names
// (e.g., xyz) but the underlying reader needs a slice of view names,
// e.g., xyz_index, so we need to add the _index suffix with
// index_table_name().
static query::partition_slice index_slice_to_view_slice(
const query::partition_slice& slice,
const schema& built_views_schema,
const schema& built_indexes_schema)
{
// Most of the slice - such as options and which columns to read -
// should be copied unchanged. Just the clustering row ranges need
// changing.
// Fix _row_ranges (used for WHERE specifying a clustering range):
query::partition_slice ret = slice;
for (query::clustering_range &range : ret._row_ranges) {
range = index_name_range_to_view_name_range(range, built_views_schema, built_indexes_schema);
}
// Fix _specific_ranges (used for continuing on paging).
auto& specific_ranges = ret.get_specific_ranges();
if (specific_ranges) {
partition_key pk = specific_ranges->pk();
std::vector<query::clustering_range> ranges;
for (const query::clustering_range &range : specific_ranges->ranges()) {
ranges.push_back(index_name_range_to_view_name_range(range, built_views_schema, built_indexes_schema));
}
ret.clear_ranges();
ret.set_range(built_indexes_schema, pk, ranges);
}
return ret;
}
built_indexes_reader(
replica::database& db,
schema_ptr schema,
reader_permit permit,
replica::column_family& built_views,
const dht::partition_range& range,
const query::partition_slice& slice,
const io_priority_class& pc,
tracing::trace_state_ptr trace_state,
streamed_mutation::forwarding fwd,
mutation_reader::forwarding fwd_mr)
: flat_mutation_reader_v2::impl(schema, permit)
, _db(db)
, _schema(std::move(schema))
, _view_names_slice(index_slice_to_view_slice(slice, *built_views.schema(), *_schema))
, _underlying(built_views.make_reader_v2(
built_views.schema(),
std::move(permit),
range,
_view_names_slice,
pc,
std::move(trace_state),
fwd,
fwd_mr)) {
}
bool is_index(const clustering_row& built_view_row) const {
auto view_name = value_cast<sstring>(utf8_type->deserialize(*built_view_row.key().begin(*_underlying.schema())));
try {
auto s = _db.find_schema(_current_keyspace, view_name);
return s->is_view() && _db.find_column_family(s->view_info()->base_id()).get_index_manager().is_index(view_ptr(s));
} catch (const replica::no_such_column_family&) {
return false;
}
}
virtual future<> fill_buffer() override {
return _underlying.fill_buffer().then([this] {
_end_of_stream = _underlying.is_end_of_stream();
while (!_underlying.is_buffer_empty()) {
auto mf = _underlying.pop_mutation_fragment();
if (mf.is_partition_start()) {
_current_keyspace = value_cast<sstring>(utf8_type->deserialize(*mf.as_partition_start().key().key().begin(*_underlying.schema())));
} else if (mf.is_clustering_row()) {
if (is_index(mf.as_clustering_row())) {
// mf's clustering key is the materialized view's
// name, xyz_index, while we need the index name
// xyz. So modify mf:
mf.mutate_as_clustering_row(*_underlying.schema(),
[&] (clustering_row& cr) mutable {
sstring view_name = value_cast<sstring>(utf8_type->deserialize(*cr.key().begin(*_underlying.schema())));
sstring index_name = ::secondary_index::index_name_from_table_name(view_name);
cr.key() = clustering_key_prefix::from_single_value(*_underlying.schema(), utf8_type->decompose(index_name));
});
} else {
continue;
}
}
push_mutation_fragment(std::move(mf));
}
});
}
virtual future<> next_partition() override {
_end_of_stream = false;
clear_buffer_to_next_partition();
if (is_buffer_empty()) {
return _underlying.next_partition();
}
return make_ready_future<>();
}
virtual future<> fast_forward_to(const dht::partition_range& pr) override {
clear_buffer();
_end_of_stream = false;
return _underlying.fast_forward_to(pr);
}
virtual future<> fast_forward_to(position_range range) override {
forward_buffer_to(range.start());
_end_of_stream = false;
// range contains index names (e.g., xyz) but the underlying table
// contains view names (e.g., xyz_index) so we need to add the
// _index suffix with index_table_name():
position_in_partition start = range.start();
position_in_partition end = range.end();
if (start.get_clustering_key_prefix()) {
clustering_key_prefix ck = index_name_to_view_name(
*start.get_clustering_key_prefix(),
*_underlying.schema(), *_schema);
start = position_in_partition(start.region(),
start.get_bound_weight(),
std::move(ck));
}
if (end.get_clustering_key_prefix()) {
clustering_key_prefix ck = index_name_to_view_name(
*end.get_clustering_key_prefix(),
*_underlying.schema(), *_schema);
start = position_in_partition(end.region(),
end.get_bound_weight(),
std::move(ck));
}
range = position_range(std::move(start), std::move(end));
return _underlying.fast_forward_to(std::move(range));
}
virtual future<> close() noexcept override {
return _underlying.close();
}
};
public:
built_indexes_virtual_reader(replica::database& db)
: _db(db) {
}
flat_mutation_reader_v2 operator()(
schema_ptr s,
reader_permit permit,
const dht::partition_range& range,
const query::partition_slice& slice,
const io_priority_class& pc,
tracing::trace_state_ptr trace_state,
streamed_mutation::forwarding fwd,
mutation_reader::forwarding fwd_mr) {
return make_flat_mutation_reader_v2<built_indexes_reader>(
_db,
std::move(s),
std::move(permit),
_db.find_column_family(s->ks_name(), system_keyspace::v3::BUILT_VIEWS),
range,
slice,
pc,
std::move(trace_state),
fwd,
fwd_mr);
}
};
}