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// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#include "attribute_limiter.h"
#include <vespa/vespalib/util/stringfmt.h>
#include <vespa/searchlib/fef/matchdatalayout.h>
#include <vespa/searchlib/query/tree/range.h>
#include <vespa/searchlib/query/tree/simplequery.h>
using namespace search::queryeval;
using namespace search::query;
using vespalib::make_string;
using vespalib::string;
namespace proton::matching {
AttributeLimiter::AttributeLimiter(Searchable &searchable_attributes,
const IRequestContext & requestContext,
const string &attribute_name,
bool descending,
const string &diversity_attribute,
double diversityCutoffFactor,
DiversityCutoffStrategy diversityCutoffStrategy)
: _searchable_attributes(searchable_attributes),
_requestContext(requestContext),
_attribute_name(attribute_name),
_descending(descending),
_diversity_attribute(diversity_attribute),
_lock(),
_match_datas(),
_blueprint(),
_estimatedHits(-1),
_diversityCutoffFactor(diversityCutoffFactor),
_diversityCutoffStrategy(diversityCutoffStrategy)
{
}
AttributeLimiter::~AttributeLimiter() = default;
namespace {
vespalib::string STRICT_STR("strict");
vespalib::string LOOSE_STR("loose");
}
AttributeLimiter::DiversityCutoffStrategy
AttributeLimiter::toDiversityCutoffStrategy(const vespalib::stringref & strategy)
{
return (strategy == STRICT_STR) ? DiversityCutoffStrategy::STRICT : DiversityCutoffStrategy::LOOSE;
}
const vespalib::string &
AttributeLimiter::toString(DiversityCutoffStrategy strategy)
{
return (strategy == DiversityCutoffStrategy::STRICT) ? STRICT_STR : LOOSE_STR;
}
SearchIterator::UP
AttributeLimiter::create_search(size_t want_hits, size_t max_group_size, bool strictSearch)
{
std::lock_guard<std::mutex> guard(_lock);
const uint32_t my_field_id = 0;
search::fef::MatchDataLayout layout;
auto my_handle = layout.allocTermField(my_field_id);
if ( ! _blueprint ) {
const uint32_t no_unique_id = 0;
string range_spec = make_string("[;;%s%zu", (_descending)? "-" : "", want_hits);
if (max_group_size < want_hits) {
size_t cutoffGroups = (_diversityCutoffFactor*want_hits)/max_group_size;
range_spec.append(make_string(";%s;%zu;%zu;%s]", _diversity_attribute.c_str(), max_group_size,
cutoffGroups, toString(_diversityCutoffStrategy).c_str()));
} else {
range_spec.push_back(']');
}
Range range(range_spec);
SimpleRangeTerm node(range, _attribute_name, no_unique_id, Weight(0));
FieldSpecList field; // single field API is protected
field.add(FieldSpec(_attribute_name, my_field_id, my_handle));
_blueprint = _searchable_attributes.createBlueprint(_requestContext, field, node);
//TODO: Put in any bitvectors from termwise eval here.
_blueprint->fetchPostings(strictSearch, nullptr);
_estimatedHits = _blueprint->getState().estimate().estHits;
_blueprint->freeze();
}
_match_datas.push_back(layout.createMatchData());
return _blueprint->createSearch(*_match_datas.back(), strictSearch);
}
}
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