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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#pragma once
#include <vespa/searchlib/fef/blueprint.h>
namespace search::features {
/**
* Implements the blueprint for the unique rank feature.
*
* This will compute a globally unique id based on lid and distribution key.
* Cheap way to get deterministic ordering
* It will change if documents change lid.
*/
class GlobalSequenceBlueprint : public fef::Blueprint
{
private:
uint32_t _distributionKey;
public:
GlobalSequenceBlueprint();
void visitDumpFeatures(const fef::IIndexEnvironment & env, fef::IDumpFeatureVisitor & visitor) const override;
fef::Blueprint::UP createInstance() const override;
fef::ParameterDescriptions getDescriptions() const override {
return fef::ParameterDescriptions();
}
bool setup(const fef::IIndexEnvironment & env, const fef::ParameterList & params) override;
fef::FeatureExecutor &createExecutor(const fef::IQueryEnvironment &env, vespalib::Stash &stash) const override;
static uint64_t globalSequence(uint32_t docId, uint32_t distrKey) {
return (1ul << 48) - ((uint64_t(docId) << 16)| distrKey);
}
};
}
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