4e5a52d6fa
The intent is to make data returned by queries always conform to a single schema version, which is requested by the client. For CQL queries, for example, we want to use the same schema which was used to compile the query. The other node expects to receive data conforming to the requested schema. Interface on shard level accepts schema_ptr, across nodes we use table_schema_version UUID. To transfer schema_ptr across shards, we use global_schema_ptr. Because schema is identified with UUID across nodes, requestors must be prepared for being queried for the definition of the schema. They must hold a live schema_ptr around the request. This guarantees that schema_registry will always know about the requested version. This is not an issue because for queries the requestor needs to hold on to the schema anyway to be able to interpret the results. But care must be taken to always use the same schema version for making the request and parsing the results. Schema requesting across nodes is currently stubbed (throws runtime exception).
123 lines
3.8 KiB
C++
123 lines
3.8 KiB
C++
/*
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* Copyright (C) 2015 Cloudius Systems, Ltd.
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*/
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/*
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* This file is part of Scylla.
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*
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* Scylla is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Scylla is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include "query-request.hh"
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#include "query-result.hh"
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#include "mutation_reader.hh"
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#include "frozen_mutation.hh"
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#include "db/serializer.hh"
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class reconcilable_result;
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class frozen_reconcilable_result;
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// Can be read by other cores after publishing.
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struct partition {
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uint32_t _row_count;
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frozen_mutation _m; // FIXME: We don't need cf UUID, which frozen_mutation includes.
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partition(uint32_t row_count, frozen_mutation m)
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: _row_count(row_count)
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, _m(std::move(m))
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{ }
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uint32_t row_count() const {
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return _row_count;
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}
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const frozen_mutation& mut() const {
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return _m;
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}
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bool operator==(const partition& other) const {
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return _row_count == other._row_count && _m.representation() == other._m.representation();
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}
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bool operator!=(const partition& other) const {
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return !(*this == other);
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}
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};
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// The partitions held by this object are ordered according to dht::decorated_key ordering and non-overlapping.
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// Each mutation must have different key.
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//
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// Can be read by other cores after publishing.
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class reconcilable_result {
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uint32_t _row_count;
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std::vector<partition> _partitions;
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public:
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~reconcilable_result();
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reconcilable_result();
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reconcilable_result(reconcilable_result&&) = default;
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reconcilable_result& operator=(reconcilable_result&&) = default;
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reconcilable_result(uint32_t row_count, std::vector<partition> partitions);
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const std::vector<partition>& partitions() const;
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std::vector<partition>& partitions();
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uint32_t row_count() const {
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return _row_count;
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}
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bool operator==(const reconcilable_result& other) const;
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bool operator!=(const reconcilable_result& other) const;
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struct printer {
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const reconcilable_result& self;
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schema_ptr schema;
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friend std::ostream& operator<<(std::ostream&, const printer&);
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};
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printer pretty_printer(schema_ptr) const;
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};
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query::result to_data_query_result(const reconcilable_result&, schema_ptr, const query::partition_slice&);
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namespace db {
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template<> serializer<reconcilable_result>::serializer(const reconcilable_result&);
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template<> void serializer<reconcilable_result>::write(output&, const reconcilable_result&);
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template<> void serializer<reconcilable_result>::read(reconcilable_result&, input&);
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extern template class serializer<reconcilable_result>;
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}
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// Performs a query on given data source returning data in reconcilable form.
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//
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// Reads at most row_limit rows. If less rows are returned, the data source
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// didn't have more live data satisfying the query.
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//
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// Any cells which have expired according to query_time are returned as
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// deleted cells and do not count towards live data. The mutations are
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// compact, meaning that any cell which is covered by higher-level tombstone
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// is absent in the results.
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//
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// 'source' doesn't have to survive deferring.
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future<reconcilable_result> mutation_query(
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schema_ptr,
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const mutation_source& source,
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const query::partition_range& range,
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const query::partition_slice& slice,
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uint32_t row_limit,
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gc_clock::time_point query_time);
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