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3c6931c1ed
Previously, constants::setter evaluated its expression using only the query options, which means expressions referencing row columns (column_value nodes) would crash or return incorrect results. Add evaluate_on_prefetched_row() to update_parameters: it evaluates an expression in the context of the prefetched row for a given (pkey, ckey), falling back to options-only evaluate() when no selection is available (non-LWT context) or no column values are needed, and treating absent columns needed by the expression as null. Extend constants::setter to use this method: - setter::execute() now calls evaluate_on_prefetched_row() or evaluate() as needed. - setter::requires_read() returns true when the expression contains a column_value node, triggering a prefetch read. - setter::requires_lwt() mirrors requires_read(), enforcing that column- referencing arithmetic is only allowed inside a conditional (IF) statement. We'll use this new feature to implement "SET r = r + 1" and similar expressions in the next patch.
79 lines
2.6 KiB
C++
79 lines
2.6 KiB
C++
/*
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* Copyright (C) 2015-present ScyllaDB
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*
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* Modified by ScyllaDB
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*/
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/*
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* SPDX-License-Identifier: (LicenseRef-ScyllaDB-Source-Available-1.1 and Apache-2.0)
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*/
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#pragma once
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#include "cql3/update_parameters.hh"
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#include "cql3/operation.hh"
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#include "cql3/values.hh"
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#include "mutation/mutation.hh"
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#include <seastar/core/shared_ptr.hh>
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namespace service::broadcast_tables {
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class update_query;
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}
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namespace cql3 {
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/**
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* Static helper methods and classes for constants.
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*/
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class constants {
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public:
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#if 0
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private static final Logger logger = LoggerFactory.getLogger(Constants.class);
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#endif
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public:
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class setter : public operation_skip_if_unset {
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bool _requires_read;
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public:
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setter(const column_definition& column, expr::expression e);
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virtual bool requires_read() const override { return _requires_read; }
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virtual bool requires_lwt() const override {
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// An expression that requires reading a value from the row, e.g.,
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// SET r = r + 1, requires LWT for atomicity and should not be allowed
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// on non-LWT requests. In one special case, namely a list update
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// "UPDATE t SET mylist[0] = 5 WHERE ...", we do allow reading the old
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// row without LWT or atomicity - but this case is not handled by
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// constants::setter so we don't need to support it here.
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return _requires_read;
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}
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virtual void execute(mutation& m, const clustering_key_prefix& prefix, const update_parameters& params) override;
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static void execute(mutation& m, const clustering_key_prefix& prefix, const update_parameters& params, const column_definition& column, cql3::raw_value_view value);
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virtual expr::expression prepare_new_value_for_broadcast_tables() const override;
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};
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struct adder final : operation_skip_if_unset {
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using operation_skip_if_unset::operation_skip_if_unset;
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virtual void execute(mutation& m, const clustering_key_prefix& prefix, const update_parameters& params) override;
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};
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struct subtracter final : operation_skip_if_unset {
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using operation_skip_if_unset::operation_skip_if_unset;
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virtual void execute(mutation& m, const clustering_key_prefix& prefix, const update_parameters& params) override;
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};
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class deleter : public operation_no_unset_support {
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public:
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deleter(const column_definition& column)
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: operation_no_unset_support(column, std::nullopt)
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{ }
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virtual void execute(mutation& m, const clustering_key_prefix& prefix, const update_parameters& params) override;
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};
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};
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}
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