26403df9ea
If a partition range is not present locally, `partition_ranges_owned_by_this_shard` assigns it to shard 0, which can overload shard 0. To address this, this commit adds a `shard_id_hint` to the mapreduce request. When `shard_id_hint` is set, the entire partition range in the request is handled by the specified shard. The `shard_id_hint` is set by the new tablet-aware mapreduce algorithm, introduced in `dispatch_to_tablets`. This algorithm balances the workload across shards, so the changes in this commit ensure that load balancing is preserved, even during events such as tablet splits. Fixes: scylladb#21831
51 lines
1.2 KiB
C++
51 lines
1.2 KiB
C++
/*
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* Copyright 2022-present ScyllaDB
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*/
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/*
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* SPDX-License-Identifier: LicenseRef-ScyllaDB-Source-Available-1.0
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*/
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#include "dht/i_partitioner_fwd.hh"
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#include "idl/read_command.idl.hh"
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#include "idl/consistency_level.idl.hh"
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namespace db {
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namespace functions {
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class function_name {
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sstring keyspace;
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sstring name;
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};
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}
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}
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namespace query {
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struct mapreduce_request {
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struct aggregation_info {
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db::functions::function_name name;
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std::vector<sstring> column_names;
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};
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enum class reduction_type : uint8_t {
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count,
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aggregate
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};
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std::vector<query::mapreduce_request::reduction_type> reduction_types;
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query::read_command cmd;
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dht::partition_range_vector pr;
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db::consistency_level cl;
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lowres_system_clock::time_point timeout;
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std::optional<std::vector<query::mapreduce_request::aggregation_info>> aggregation_infos [[version 5.1]];
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std::optional<shard_id> shard_id_hint [[version 2025.3]];
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};
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struct mapreduce_result {
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std::vector<bytes_opt> query_results;
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};
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verb [[cancellable]] mapreduce_request(query::mapreduce_request req [[ref]], std::optional<tracing::trace_info> trace_info [[ref]]) -> query::mapreduce_result;
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}
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