323e5cd171
The PRUNE MATERALIZED VIEW statement is performed as follows: 1. Perform a range scan of the view table from the view replicas based on the ranges specified in the statement. 2. While reading the paged scan above, for each view row perform a read from all base replicas at the corresponding primary key. If a discrepancy is detected, delete the row in the view table. When reading multiple rows, this is very slow because for each view row we need to performe a single row query on multiple replicas. In this patch we add an option to speed this up by performing many of the single base row reads concurrently, at the concurrency specified in the USING CONCURRENCY clause. Fixes https://github.com/scylladb/scylladb/issues/27070
62 lines
1.8 KiB
C++
62 lines
1.8 KiB
C++
/*
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* SPDX-License-Identifier: LicenseRef-ScyllaDB-Source-Available-1.0
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*/
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/* Copyright 2022-present ScyllaDB */
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#pragma once
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#include "query/query-result-reader.hh"
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#include "replica/database_fwd.hh"
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#include "db/timeout_clock.hh"
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#include <seastar/core/future.hh>
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#include <seastar/core/gate.hh>
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namespace service {
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class storage_proxy;
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class query_state;
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}
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namespace db::view {
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class delete_ghost_rows_visitor {
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service::storage_proxy& _proxy;
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service::query_state& _state;
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db::timeout_clock::duration _timeout_duration;
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view_ptr _view;
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replica::table& _view_table;
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schema_ptr _base_schema;
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std::optional<partition_key> _view_pk;
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db::timeout_semaphore _concurrency_semaphore;
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seastar::gate _gate;
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std::exception_ptr& _ex;
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public:
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delete_ghost_rows_visitor(service::storage_proxy& proxy, service::query_state& state, view_ptr view, db::timeout_clock::duration timeout_duration, size_t concurrency, std::exception_ptr& ex);
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delete_ghost_rows_visitor(delete_ghost_rows_visitor&&) = default;
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~delete_ghost_rows_visitor() noexcept;
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void add_value(const column_definition& def, query::result_row_view::iterator_type& i) {
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}
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void accept_new_partition(const partition_key& key, uint32_t row_count);
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void accept_new_partition(uint32_t row_count) {
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}
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// Assumes running in seastar::thread
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void accept_new_row(const clustering_key& ck, const query::result_row_view& static_row, const query::result_row_view& row);
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void accept_new_row(const query::result_row_view& static_row, const query::result_row_view& row) {
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}
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uint32_t accept_partition_end(const query::result_row_view& static_row) {
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return 0;
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}
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private:
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future<> do_accept_new_row(partition_key pk, clustering_key ck);
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};
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} //namespace db::view
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