a32e8091a9
This commit adds a function that compares split mutations with the `row_state`, that was selected as a preimage or propagated through cdc options by a caller. If the items are equal, the corresponding log row isn't generated. The result being that creating an item with BatchWriteItem, PutItem, or UpdateItem doesn't emit an INSERT/MODIFY event if exactly identical item already exists. Comparing the items may be costly, so this logic is controlled by `alternator_streams_compabitiblity` flag. This commit handles the following cases: - `PutItem/UpdateItem/BatchWriteItem.PutItem of an existing and equal item: nothing`
80 lines
3.9 KiB
C++
80 lines
3.9 KiB
C++
/*
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* Copyright (C) 2020-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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#pragma once
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#include <boost/dynamic_bitset.hpp> // IWYU pragma: keep
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#include "cdc/log.hh"
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#include "replica/database_fwd.hh"
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#include "mutation/timestamp.hh"
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class mutation;
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namespace cdc {
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// Represents a set of column ids of one kind (partition key, clustering key, regular row or static row).
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// There already exists a column_set type, but it keeps ordinal_column_ids, not column_ids (ordinal column ids
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// are unique across whole table, while kind-specific ids are unique only within one column kind).
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// To avoid converting back and forth between ordinal and kind-specific ids, one_kind_column_set is used instead.
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using one_kind_column_set = boost::dynamic_bitset<uint64_t>;
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// An object that processes changes from a single, big mutation.
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// It is intended to be used with process_changes_xxx_splitting. Those functions define the order and layout in which
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// changes should appear in CDC log, and change_processor is responsible for producing CDC log rows from changes given
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// by those two functions.
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//
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// The flow of calling its methods should go as follows:
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// -> begin_timestamp #1
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// -> produce_preimage (one call for each preimage row to be generated)
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// -> process_change (one call for each part generated by the splitting function)
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// -> produce_postimage (one call for each postimage row to be generated)
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// -> begin_timestamp #2
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// ...
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class change_processor {
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protected:
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~change_processor() {};
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public:
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// Tells the processor that changes that follow from now on will be of given timestamp.
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// This method must be called in increasing timestamp order.
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// begin_timestamp can be called only once for a given timestamp and change_processor object.
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// ts - timestamp of mutation parts
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// is_last - determines if this will be the last timestamp to be processed by this change_processor instance.
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virtual void begin_timestamp(api::timestamp_type ts, bool is_last) = 0;
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// Tells the processor to produce a preimage for a given clustering/static row.
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// ck - clustering key of the row for which to produce a preimage; if nullptr, static row preimage is requested
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// columns_to_include - include information about the current state of those columns only, leave others as null
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virtual void produce_preimage(const clustering_key* ck, const one_kind_column_set& columns_to_include) = 0;
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// Tells the processor to produce a postimage for a given clustering/static row.
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// Contrary to preimage, this requires data from all columns to be present.
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// ck - clustering key of the row for which to produce a postimage; if nullptr, static row postimage is requested
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virtual void produce_postimage(const clustering_key* ck) = 0;
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// Processes a smaller mutation which is a subset of the big mutation.
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// The mutation provided to process_change should be simple enough for it to be possible to convert it
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// into CDC log rows - for example, it cannot represent a write to two columns of the same row, where
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// both columns have different timestamp or TTL set.
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// m - the small mutation to be converted into CDC log rows.
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virtual void process_change(const mutation& m) = 0;
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// Tells processor we have reached end of record - last part
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// of a given timestamp batch
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virtual void end_record() = 0;
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virtual const row_states_map& clustering_row_states() const = 0;
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};
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bool should_split(const mutation& base_mutation, const per_request_options& options);
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void process_changes_with_splitting(const mutation& base_mutation, change_processor& processor,
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bool enable_preimage, bool enable_postimage, bool alternator_strict_compatibility);
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void process_changes_without_splitting(const mutation& base_mutation, change_processor& processor,
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bool enable_preimage, bool enable_postimage, bool alternator_strict_compatibility);
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}
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