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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#include "match_phase_limiter.h"
#include <vespa/searchlib/queryeval/andsearchstrict.h>
#include <vespa/vespalib/data/slime/cursor.h>
#include <vespa/log/log.h>
LOG_SETUP(".proton.matching.match_phase_limiter");
using search::queryeval::SearchIterator;
using search::queryeval::Searchable;
using search::queryeval::IRequestContext;
namespace proton::matching {
namespace {
template<bool PRE_FILTER>
class LimitedSearchT : public LimitedSearch {
public:
LimitedSearchT(SearchIterator::UP limiter, SearchIterator::UP search) :
LimitedSearch(std::move(PRE_FILTER ? limiter : search),
std::move(PRE_FILTER ? search : limiter))
{
}
void doUnpack(uint32_t docId) override {
if (PRE_FILTER) {
getSecond().doUnpack(docId);
} else {
getFirst().doUnpack(docId);
}
}
};
} // namespace proton::matching::<unnamed>
void
LimitedSearch::doSeek(uint32_t docId)
{
uint32_t currentId(docId);
for (; !isAtEnd(currentId); currentId++) {
_first->seek(currentId);
currentId = _first->getDocId();
if (isAtEnd(currentId)) {
break;
}
if (_second->seek(currentId)) {
break;
}
}
setDocId(currentId);
}
void
LimitedSearch::initRange(uint32_t begin, uint32_t end) {
SearchIterator::initRange(begin, end);
getFirst().initRange(begin, end);
getSecond().initRange(begin, end);
}
void
LimitedSearch::visitMembers(vespalib::ObjectVisitor &visitor) const
{
visit(visitor, "first", getFirst());
visit(visitor, "second", getSecond());
}
MatchPhaseLimiter::MatchPhaseLimiter(uint32_t docIdLimit,
const RangeQueryLocator & rangeQueryLocator,
Searchable &searchable_attributes,
IRequestContext & requestContext,
const DegradationParams & degradation,
const DiversityParams &diversity)
: _postFilterMultiplier(degradation.post_filter_multiplier),
_maxFilterCoverage(degradation.max_filter_coverage),
_calculator(degradation.max_hits, diversity.min_groups, degradation.sample_percentage),
_limiter_factory(rangeQueryLocator, searchable_attributes, requestContext,
degradation.attribute, degradation.descending,
diversity.attribute, diversity.cutoff_factor, diversity.cutoff_strategy),
_coverage(docIdLimit)
{ }
MatchPhaseLimiter::~MatchPhaseLimiter() = default;
namespace {
template <bool PRE_FILTER>
SearchIterator::UP
do_limit(AttributeLimiter &limiter_factory, SearchIterator::UP search,
size_t wanted_num_docs, size_t max_group_size,
uint32_t current_id, uint32_t end_id)
{
SearchIterator::UP limiter = limiter_factory.create_search(wanted_num_docs, max_group_size, PRE_FILTER);
limiter = search->andWith(std::move(limiter), wanted_num_docs);
if (limiter) {
search = std::make_unique<LimitedSearchT<PRE_FILTER>>(std::move(limiter), std::move(search));
}
search->initRange(current_id + 1, end_id);
return search;
}
} // namespace proton::matching::<unnamed>
SearchIterator::UP
MatchPhaseLimiter::maybe_limit(SearchIterator::UP search, double match_freq, size_t num_docs, Cursor * trace)
{
size_t wanted_num_docs = _calculator.wanted_num_docs(match_freq);
size_t max_filter_docs = static_cast<size_t>(num_docs * _maxFilterCoverage);
size_t upper_limited_corpus_size = std::min(num_docs, max_filter_docs);
if (trace) {
trace->setDouble("hit_rate", match_freq);
trace->setLong("num_docs", num_docs);
trace->setLong("max_filter_docs", max_filter_docs);
trace->setLong("wanted_docs", wanted_num_docs);
}
if (upper_limited_corpus_size <= wanted_num_docs) {
if (trace) {
trace->setString("action", "Will not limit !");
}
LOG(debug, "Will not limit ! maybe_limit(hit_rate=%g, num_docs=%ld, max_filter_docs=%ld) = wanted_num_docs=%ld",
match_freq, num_docs, max_filter_docs, wanted_num_docs);
return search;
}
uint32_t current_id = search->getDocId();
uint32_t end_id = search->getEndId();
size_t total_query_hits = _calculator.estimated_hits(match_freq, num_docs);
size_t max_group_size = _calculator.max_group_size(wanted_num_docs);
bool use_pre_filter = (wanted_num_docs < (total_query_hits * _postFilterMultiplier));
if (trace) {
trace->setString("action", use_pre_filter ? "Will limit with prefix filter" : "Will limit with postfix filter");
trace->setLong("max_group_size", max_group_size);
trace->setLong("current_docid", current_id);
trace->setLong("end_docid", end_id);
trace->setLong("estimated_total_hits", total_query_hits);
}
LOG(debug, "Will do %s filter : maybe_limit(hit_rate=%g, num_docs=%zu, max_filter_docs=%ld) = wanted_num_docs=%zu,"
" max_group_size=%zu, current_docid=%u, end_docid=%u, total_query_hits=%ld",
use_pre_filter ? "pre" : "post", match_freq, num_docs, max_filter_docs, wanted_num_docs,
max_group_size, current_id, end_id, total_query_hits);
return (use_pre_filter)
? do_limit<true>(_limiter_factory, std::move(search), wanted_num_docs, max_group_size, current_id, end_id)
: do_limit<false>(_limiter_factory, std::move(search), wanted_num_docs, max_group_size, current_id, end_id);
}
void
MatchPhaseLimiter::updateDocIdSpaceEstimate(size_t searchedDocIdSpace, size_t remainingDocIdSpace)
{
_coverage.update(searchedDocIdSpace, remainingDocIdSpace, _limiter_factory.getEstimatedHits());
}
size_t
MatchPhaseLimiter::getDocIdSpaceEstimate() const
{
return _coverage.getEstimate();
}
}
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