#include <HashtableRecycler.h>

Inheritance diagram for HashtableRecycler:

Collaboration diagram for HashtableRecycler:

Public Member Functions
	HashtableRecycler (CacheItemType hashtable_type, int num_gpus)

void	putItemToCache (QueryPlanHash key, std::shared_ptr< HashTable > item_ptr, CacheItemType item_type, DeviceIdentifier device_identifier, size_t item_size, size_t compute_time, std::optional< HashtableCacheMetaInfo > meta_info=std::nullopt) override

void	initCache () override

void	clearCache () override

void	markCachedItemAsDirty (size_t table_key, std::unordered_set< QueryPlanHash > &key_set, CacheItemType item_type, DeviceIdentifier device_identifier) override

std::string	toString () const override

bool	checkOverlapsHashtableBucketCompatability (const OverlapsHashTableMetaInfo &candidate_bucket_dim, const OverlapsHashTableMetaInfo &target_bucket_dim) const

std::tuple< QueryPlanHash, std::shared_ptr< HashTable > , std::optional < HashtableCacheMetaInfo > >	getCachedHashtableWithoutCacheKey (std::set< size_t > &visited, CacheItemType hash_table_type, DeviceIdentifier device_identifier)

void	addQueryPlanDagForTableKeys (size_t hashed_query_plan_dag, const std::unordered_set< size_t > &table_keys)

std::optional < std::unordered_set< size_t > >	getMappedQueryPlanDagsWithTableKey (size_t table_key) const

void	removeTableKeyInfoFromQueryPlanDagMap (size_t table_key)

Public Member Functions inherited from DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >
	DataRecycler (const std::vector< CacheItemType > &item_types, size_t total_cache_size, size_t max_item_size, int num_gpus)

virtual	~DataRecycler ()=default

virtual std::shared_ptr < HashTable >	getItemFromCache (QueryPlanHash key, CacheItemType item_type, DeviceIdentifier device_identifier, std::optional< HashtableCacheMetaInfo > meta_info=std::nullopt)=0

void	markCachedItemAsDirtyImpl (QueryPlanHash key, CachedItemContainer &m) const

bool	isCachedItemDirty (QueryPlanHash key, CachedItemContainer &m) const

std::shared_ptr < CachedItemContainer >	getCachedItemContainer (CacheItemType item_type, DeviceIdentifier device_identifier) const

std::optional< CachedItem < std::shared_ptr< HashTable > , HashtableCacheMetaInfo > >	getCachedItemWithoutConsideringMetaInfo (QueryPlanHash key, CacheItemType item_type, DeviceIdentifier device_identifier, CachedItemContainer &m, std::lock_guard< std::mutex > &lock)

size_t	getCurrentNumCachedItems (CacheItemType item_type, DeviceIdentifier device_identifier) const

size_t	getCurrentNumDirtyCachedItems (CacheItemType item_type, DeviceIdentifier device_identifier) const

size_t	getCurrentNumCleanCachedItems (CacheItemType item_type, DeviceIdentifier device_identifier) const

size_t	getCurrentCacheSizeForDevice (CacheItemType item_type, DeviceIdentifier device_identifier) const

std::shared_ptr< CacheItemMetric >	getCachedItemMetric (CacheItemType item_type, DeviceIdentifier device_identifier, QueryPlanHash key) const

void	setTotalCacheSize (CacheItemType item_type, size_t new_total_cache_size)

void	setMaxCacheItemSize (CacheItemType item_type, size_t new_max_cache_item_size)

Static Public Member Functions
static HashtableAccessPathInfo	getHashtableAccessPathInfo (const std::vector< InnerOuter > &inner_outer_pairs, const std::vector< InnerOuterStringOpInfos > &inner_outer_string_op_infos_pairs, const SQLOps op_type, const JoinType join_type, const HashTableBuildDagMap &hashtable_build_dag_map, int device_count, int shard_count, const std::vector< std::vector< Fragmenter_Namespace::FragmentInfo >> &frags_for_device, Executor *executor)

static size_t	getJoinColumnInfoHash (std::vector< const Analyzer::ColumnVar * > &inner_cols, std::vector< const Analyzer::ColumnVar * > &outer_cols, Executor *executor)

static bool	isSafeToCacheHashtable (const TableIdToNodeMap &table_id_to_node_map, bool need_dict_translation, const std::vector< InnerOuterStringOpInfos > &inner_outer_string_op_info_pairs, const shared::TableKey &table_key)

static bool	isInvalidHashTableCacheKey (const std::vector< QueryPlanHash > &cache_keys)

Public Attributes
	g_hashtable_cache_total_bytes

	g_max_cacheable_hashtable_size_bytes

	num_gpus

Private Member Functions
bool	hasItemInCache (QueryPlanHash key, CacheItemType item_type, DeviceIdentifier device_identifier, std::lock_guard< std::mutex > &lock, std::optional< HashtableCacheMetaInfo > meta_info=std::nullopt) const override

void	removeItemFromCache (QueryPlanHash key, CacheItemType item_type, DeviceIdentifier device_identifier, std::lock_guard< std::mutex > &lock, std::optional< HashtableCacheMetaInfo > meta_info=std::nullopt) override

void	cleanupCacheForInsertion (CacheItemType item_type, DeviceIdentifier device_identifier, size_t required_size, std::lock_guard< std::mutex > &lock, std::optional< HashtableCacheMetaInfo > meta_info=std::nullopt) override

void	removeCachedHashtableBuiltFromSyntheticTable (CacheItemType item_type, DeviceIdentifier device_identifier, std::lock_guard< std::mutex > &lock)

Private Attributes
std::unordered_map< size_t, std::unordered_set< size_t > >	table_key_to_query_plan_dag_map_

Additional Inherited Members
Public Types inherited from DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >
using	CachedItemContainer = std::vector< CachedItem< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >>

using	PerDeviceCacheItemContainer = std::unordered_map< DeviceIdentifier, std::shared_ptr< CachedItemContainer >>

using	PerTypeCacheItemContainer = std::unordered_map< CacheItemType, std::shared_ptr< PerDeviceCacheItemContainer >>

using	PerTypeCacheMetricTracker = std::unordered_map< CacheItemType, CacheMetricTracker >

Protected Member Functions inherited from DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >
void	removeCachedItemFromBeginning (CacheItemType item_type, DeviceIdentifier device_identifier, int offset)

void	sortCacheContainerByQueryMetric (CacheItemType item_type, DeviceIdentifier device_identifier)

std::mutex &	getCacheLock () const

CacheMetricTracker &	getMetricTracker (CacheItemType item_type)

CacheMetricTracker const &	getMetricTracker (CacheItemType item_type) const

std::unordered_set < CacheItemType > const &	getCacheItemType () const

PerTypeCacheItemContainer const &	getItemCache () const

Detailed Description

Definition at line 53 of file HashtableRecycler.h.

Constructor & Destructor Documentation

HashtableRecycler::HashtableRecycler	(	CacheItemType	hashtable_type,
		int	num_gpus
	)

inline

Definition at line 56 of file HashtableRecycler.h.

57 : DataRecycler({hashtable_type},

DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::DataRecycler

DataRecycler(const std::vector< CacheItemType > &item_types, size_t total_cache_size, size_t max_item_size, int num_gpus)

Definition: DataRecycler.h:458

Member Function Documentation

void HashtableRecycler::addQueryPlanDagForTableKeys	(	size_t	hashed_query_plan_dag,
		const std::unordered_set< size_t > &	table_keys
	)

Definition at line 508 of file HashtableRecycler.cpp.

References DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getCacheLock(), and table_key_to_query_plan_dag_map_.

                                                 {
   std::lock_guard<std::mutex> lock(getCacheLock());
   for (auto table_key : table_keys) {
     auto itr = table_key_to_query_plan_dag_map_.try_emplace(table_key).first;
     itr->second.insert(hashed_query_plan_dag);
   }
 }

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bool HashtableRecycler::checkOverlapsHashtableBucketCompatability	(	const OverlapsHashTableMetaInfo &	candidate_bucket_dim,
		const OverlapsHashTableMetaInfo &	target_bucket_dim
	)		const

Definition at line 329 of file HashtableRecycler.cpp.

References OverlapsHashTableMetaInfo::bucket_sizes, OverlapsHashTableMetaInfo::overlaps_bucket_threshold, and OverlapsHashTableMetaInfo::overlaps_max_table_size_bytes.

Referenced by hasItemInCache(), and putItemToCache().

                                                    {
   if (candidate.bucket_sizes.size() != target.bucket_sizes.size()) {
     return false;
   }
   for (size_t i = 0; i < candidate.bucket_sizes.size(); i++) {
     if (std::abs(target.bucket_sizes[i] - candidate.bucket_sizes[i]) > 1e-4) {
       return false;
     }
   }
   auto threshold_check =
       candidate.overlaps_bucket_threshold == target.overlaps_bucket_threshold;
   auto hashtable_size_check =
       candidate.overlaps_max_table_size_bytes == target.overlaps_max_table_size_bytes;
   return threshold_check && hashtable_size_check;
 }

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void HashtableRecycler::cleanupCacheForInsertion	(	CacheItemType	item_type,
		DeviceIdentifier	device_identifier,
		size_t	required_size,
		std::lock_guard< std::mutex > &	lock,
		std::optional< HashtableCacheMetaInfo >	meta_info = `std::nullopt`
	)

overrideprivatevirtual

Implements DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >.

Definition at line 202 of file HashtableRecycler.cpp.

References g_is_test_env, DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getMetricTracker(), REMOVE, DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::removeCachedItemFromBeginning(), and DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::sortCacheContainerByQueryMetric().

Referenced by putItemToCache().

                                                    {
   // sort the vector based on the importance of the cached items (by # referenced, size
   // and compute time) and then remove unimportant cached items
   int elimination_target_offset = 0;
   size_t removed_size = 0;
   auto& metric_tracker = getMetricTracker(item_type);
   auto actual_space_to_free = metric_tracker.getTotalCacheSize() / 2;
   if (!g_is_test_env && required_size < actual_space_to_free) {
     // remove enough items to avoid too frequent cache cleanup
     // we do not apply thin to test code since test scenarios are designed to
     // specific size of items and their caches
     required_size = actual_space_to_free;
   }
   metric_tracker.sortCacheInfoByQueryMetric(device_identifier);
   auto cached_item_metrics = metric_tracker.getCacheItemMetrics(device_identifier);
   sortCacheContainerByQueryMetric(item_type, device_identifier);
 
   // collect targets to eliminate
   for (auto& metric : cached_item_metrics) {
     auto target_size = metric->getMemSize();
     ++elimination_target_offset;
     removed_size += target_size;
     if (removed_size > required_size) {
       break;
     }
   }
 
   // eliminate targets in 1) cache container and 2) their metrics
   removeCachedItemFromBeginning(item_type, device_identifier, elimination_target_offset);
   metric_tracker.removeMetricFromBeginning(device_identifier, elimination_target_offset);
 
   // update the current cache size after this cleanup
   metric_tracker.updateCurrentCacheSize(
       device_identifier, CacheUpdateAction::REMOVE, removed_size);
 }

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void HashtableRecycler::clearCache ( )

overridevirtual

Implements DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >.

Definition at line 243 of file HashtableRecycler.cpp.

References CacheMetricTracker::clearCacheMetricTracker(), DataRecyclerUtil::CPU_DEVICE_IDENTIFIER, DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getCacheItemType(), DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getCacheLock(), DataRecyclerUtil::getDeviceIdentifierString(), DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getItemCache(), DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getMetricTracker(), table_key_to_query_plan_dag_map_, and VLOG.

                                    {
   std::lock_guard<std::mutex> lock(getCacheLock());
   for (auto& item_type : getCacheItemType()) {
     getMetricTracker(item_type).clearCacheMetricTracker();
     auto item_cache = getItemCache().find(item_type)->second;
     for (auto& kv : *item_cache) {
       if (!kv.second->empty()) {
         VLOG(1) << "[" << item_type << ", "
                 << DataRecyclerUtil::getDeviceIdentifierString(
                        DataRecyclerUtil::CPU_DEVICE_IDENTIFIER)
                 << "] clear cache (# items: " << kv.second->size() << ")";
         kv.second->clear();
       }
     }
   }
   table_key_to_query_plan_dag_map_.clear();
 }

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std::tuple< QueryPlanHash, std::shared_ptr< HashTable >, std::optional< HashtableCacheMetaInfo > > HashtableRecycler::getCachedHashtableWithoutCacheKey	(	std::set< size_t > &	visited,
		CacheItemType	hash_table_type,
		DeviceIdentifier	device_identifier
	)

Definition at line 495 of file HashtableRecycler.cpp.

References EMPTY_HASHED_PLAN_DAG_KEY, DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getCachedItemContainer(), and DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getCacheLock().

                                                                                          {
   std::lock_guard<std::mutex> lock(getCacheLock());
   auto hashtable_cache = getCachedItemContainer(hash_table_type, device_identifier);
   for (auto& ht : *hashtable_cache) {
     if (!visited.count(ht.key)) {
       return std::make_tuple(ht.key, ht.cached_item, ht.meta_info);
     }
   }
   return std::make_tuple(EMPTY_HASHED_PLAN_DAG_KEY, nullptr, std::nullopt);
 }

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HashtableAccessPathInfo HashtableRecycler::getHashtableAccessPathInfo	(	const std::vector< InnerOuter > &	inner_outer_pairs,
		const std::vector< InnerOuterStringOpInfos > &	inner_outer_string_op_infos_pairs,
		const SQLOps	op_type,
		const JoinType	join_type,
		const HashTableBuildDagMap &	hashtable_build_dag_map,
		int	device_count,
		int	shard_count,
		const std::vector< std::vector< Fragmenter_Namespace::FragmentInfo >> &	frags_for_device,
		Executor *	executor
	)

static

Definition at line 413 of file HashtableRecycler.cpp.

References CHECK_GE, CHECK_GT, HashJoin::collectFragmentIds(), EMPTY_HASHED_PLAN_DAG_KEY, getJoinColumnInfoHash(), HashtableAccessPathInfo::hashed_query_plan_dag, kDirect, HashtableAccessPathInfo::table_keys, and toString().

Referenced by PerfectJoinHashTable::reify(), RangeJoinHashTable::reifyWithLayout(), OverlapsJoinHashTable::reifyWithLayout(), and BaselineJoinHashTable::reifyWithLayout().

                         {
   CHECK_GT(device_count, (int)0);
   CHECK_GE(shard_count, (int)0);
   std::vector<const Analyzer::ColumnVar*> inner_cols_vec, outer_cols_vec;
   size_t join_qual_info = EMPTY_HASHED_PLAN_DAG_KEY;
   for (auto& join_col_pair : inner_outer_pairs) {
     inner_cols_vec.push_back(join_col_pair.first);
     // extract inner join col's id
     // b/c when the inner col comes from a subquery's resulset,
     // table id / rte_index can be different even if we have the same
     // subquery's semantic, i.e., project col A from table T
     boost::hash_combine(join_qual_info,
                         executor->getQueryPlanDagCache().getJoinColumnsInfoHash(
                             join_col_pair.first, JoinColumnSide::kDirect, true));
     boost::hash_combine(join_qual_info, op_type);
     boost::hash_combine(join_qual_info, join_type);
     auto outer_col_var = dynamic_cast<const Analyzer::ColumnVar*>(join_col_pair.second);
     boost::hash_combine(join_qual_info, join_col_pair.first->get_type_info().toString());
     if (outer_col_var) {
       outer_cols_vec.push_back(outer_col_var);
       if (join_col_pair.first->get_type_info().is_dict_encoded_string()) {
         // add comp param for dict encoded string
         boost::hash_combine(join_qual_info,
                             executor->getQueryPlanDagCache().getJoinColumnsInfoHash(
                                 outer_col_var, JoinColumnSide::kDirect, true));
         boost::hash_combine(join_qual_info, outer_col_var->get_type_info().toString());
       }
     }
   }
 
   if (inner_outer_string_op_infos_pairs.size()) {
     boost::hash_combine(join_qual_info, ::toString(inner_outer_string_op_infos_pairs));
   }
 
   auto join_cols_info = getJoinColumnInfoHash(inner_cols_vec, outer_cols_vec, executor);
   HashtableAccessPathInfo access_path_info(device_count);
   auto it = hashtable_build_dag_map.find(join_cols_info);
   if (it != hashtable_build_dag_map.end()) {
     size_t hashtable_access_path = EMPTY_HASHED_PLAN_DAG_KEY;
     boost::hash_combine(hashtable_access_path, it->second.inner_cols_access_path);
     boost::hash_combine(hashtable_access_path, join_qual_info);
     if (inner_cols_vec.front()->get_type_info().is_dict_encoded_string()) {
       boost::hash_combine(hashtable_access_path, it->second.outer_cols_access_path);
     }
     boost::hash_combine(hashtable_access_path, shard_count);
 
     if (!shard_count) {
       const auto frag_list = HashJoin::collectFragmentIds(frags_for_device[0]);
       auto cache_key_for_device = hashtable_access_path;
       // no sharding, so all devices have the same fragments
       boost::hash_combine(cache_key_for_device, frag_list);
       for (int i = 0; i < device_count; ++i) {
         access_path_info.hashed_query_plan_dag[i] = cache_key_for_device;
       }
     } else {
       // we need to retrieve specific fragments for each device
       // and consider them to make a cache key for it
       for (int i = 0; i < device_count; ++i) {
         const auto frag_list_for_device =
             HashJoin::collectFragmentIds(frags_for_device[i]);
         auto cache_key_for_device = hashtable_access_path;
         boost::hash_combine(cache_key_for_device, frag_list_for_device);
         access_path_info.hashed_query_plan_dag[i] = cache_key_for_device;
       }
     }
     access_path_info.table_keys = it->second.inputTableKeys;
   }
   return access_path_info;
 }

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size_t HashtableRecycler::getJoinColumnInfoHash	(	std::vector< const Analyzer::ColumnVar * > &	inner_cols,
		std::vector< const Analyzer::ColumnVar * > &	outer_cols,
		Executor *	executor
	)

static

Definition at line 347 of file HashtableRecycler.cpp.

References EMPTY_HASHED_PLAN_DAG_KEY.

Referenced by getHashtableAccessPathInfo().

                         {
   auto hashed_join_col_info = EMPTY_HASHED_PLAN_DAG_KEY;
   boost::hash_combine(
       hashed_join_col_info,
       executor->getQueryPlanDagCache().translateColVarsToInfoHash(inner_cols, false));
   boost::hash_combine(
       hashed_join_col_info,
       executor->getQueryPlanDagCache().translateColVarsToInfoHash(outer_cols, false));
   return hashed_join_col_info;
 }

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std::optional< std::unordered_set< size_t > > HashtableRecycler::getMappedQueryPlanDagsWithTableKey ( size_t table_key ) const

Definition at line 519 of file HashtableRecycler.cpp.

References DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getCacheLock(), and table_key_to_query_plan_dag_map_.

                                                                             {
   std::lock_guard<std::mutex> lock(getCacheLock());
   auto it = table_key_to_query_plan_dag_map_.find(table_key);
   return it != table_key_to_query_plan_dag_map_.end() ? std::make_optional(it->second)
                                                       : std::nullopt;
 }

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bool HashtableRecycler::hasItemInCache	(	QueryPlanHash	key,
		CacheItemType	item_type,
		DeviceIdentifier	device_identifier,
		std::lock_guard< std::mutex > &	lock,
		std::optional< HashtableCacheMetaInfo >	meta_info = `std::nullopt`
	)		const

overrideprivatevirtual

Implements DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >.

Definition at line 21 of file HashtableRecycler.cpp.

References CHECK, checkOverlapsHashtableBucketCompatability(), EMPTY_HASHED_PLAN_DAG_KEY, g_enable_data_recycler, g_use_hashtable_cache, DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getCachedItemContainer(), and OVERLAPS_HT.

Referenced by putItemToCache().

                                                          {
   if (!g_enable_data_recycler || !g_use_hashtable_cache ||
       key == EMPTY_HASHED_PLAN_DAG_KEY) {
     return false;
   }
   auto hashtable_cache = getCachedItemContainer(item_type, device_identifier);
   // hashtable cache of the *any* device type should be properly initialized
   CHECK(hashtable_cache);
   auto candidate_ht_it = std::find_if(
       hashtable_cache->begin(), hashtable_cache->end(), [&key](const auto& cached_item) {
         return cached_item.key == key;
       });
   if (candidate_ht_it != hashtable_cache->end()) {
     if (item_type == OVERLAPS_HT) {
       CHECK(candidate_ht_it->meta_info && candidate_ht_it->meta_info->overlaps_meta_info);
       CHECK(meta_info && meta_info->overlaps_meta_info);
       if (checkOverlapsHashtableBucketCompatability(
               *candidate_ht_it->meta_info->overlaps_meta_info,
               *meta_info->overlaps_meta_info)) {
         return true;
       }
     } else {
       return true;
     }
   }
   return false;
 }

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void HashtableRecycler::initCache ( )

inlineoverridevirtual

Implements DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >.

Definition at line 78 of file HashtableRecycler.h.

78 {}

bool HashtableRecycler::isInvalidHashTableCacheKey ( const std::vector< QueryPlanHash > & cache_keys )

static

Definition at line 405 of file HashtableRecycler.cpp.

References anonymous_namespace{QueryMemoryDescriptor.cpp}::any_of(), and EMPTY_HASHED_PLAN_DAG_KEY.

Referenced by PerfectJoinHashTable::reify(), RangeJoinHashTable::reifyWithLayout(), OverlapsJoinHashTable::reifyWithLayout(), and BaselineJoinHashTable::reifyWithLayout().

                                                 {
   return cache_keys.empty() ||
          std::any_of(cache_keys.cbegin(), cache_keys.cend(), [](QueryPlanHash key) {
            return key == EMPTY_HASHED_PLAN_DAG_KEY;
          });
 }

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bool HashtableRecycler::isSafeToCacheHashtable	(	const TableIdToNodeMap &	table_id_to_node_map,
		bool	need_dict_translation,
		const std::vector< InnerOuterStringOpInfos > &	inner_outer_string_op_info_pairs,
		const shared::TableKey &	table_key
	)

static

Definition at line 361 of file HashtableRecycler.cpp.

References shared::TableKey::db_id, and shared::TableKey::table_id.

Referenced by PerfectJoinHashTable::initHashTableForDevice(), BaselineJoinHashTable::initHashTableForDevice(), PerfectJoinHashTable::reify(), and BaselineJoinHashTable::reifyWithLayout().

                                      {
   // if hashtable is built from subquery's resultset we need to check
   // 1) whether resulset rows can have inconsistency, e.g., rows can randomly be
   // permutated per execution and 2) whether it needs dictionary translation for hashtable
   // building to recycle the hashtable safely
   auto getNodeByTableId =
       [&table_id_to_node_map](
           const shared::TableKey& table_key_param) -> const RelAlgNode* {
     auto it = table_id_to_node_map.find(table_key_param);
     if (it != table_id_to_node_map.end()) {
       return it->second;
     }
     return nullptr;
   };
   bool found_sort_node = false;
   bool found_project_node = false;
   if (table_key.table_id < 0) {
     const auto origin_table_id = table_key.table_id * -1;
     const auto inner_node = getNodeByTableId({table_key.db_id, origin_table_id});
     if (!inner_node) {
       // we have to keep the node info of temporary resultset
       // so in this case we are not safe to recycle the hashtable
       return false;
     }
     // it is not safe to recycle the hashtable when
     // this resultset may have resultset ordering inconsistency and/or
     // need dictionary translation for hashtable building
     auto sort_node = dynamic_cast<const RelSort*>(inner_node);
     if (sort_node) {
       found_sort_node = true;
     } else {
       auto project_node = dynamic_cast<const RelProject*>(inner_node);
       if (project_node) {
         found_project_node = true;
       }
     }
   }
   return !(found_sort_node || (found_project_node && need_dict_translation));
 }

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void HashtableRecycler::markCachedItemAsDirty	(	size_t	table_key,
		std::unordered_set< QueryPlanHash > &	key_set,
		CacheItemType	item_type,
		DeviceIdentifier	device_identifier
	)

overridevirtual

Implements DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >.

Definition at line 261 of file HashtableRecycler.cpp.

References g_enable_data_recycler, g_use_hashtable_cache, DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getCachedItemContainer(), DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getCacheLock(), DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::markCachedItemAsDirtyImpl(), removeCachedHashtableBuiltFromSyntheticTable(), and removeTableKeyInfoFromQueryPlanDagMap().

                                                                                   {
   if (!g_enable_data_recycler || !g_use_hashtable_cache || key_set.empty()) {
     return;
   }
   std::lock_guard<std::mutex> lock(getCacheLock());
   auto hashtable_cache = getCachedItemContainer(item_type, device_identifier);
   for (auto key : key_set) {
     markCachedItemAsDirtyImpl(key, *hashtable_cache);
   }
   // after marking all cached hashtable having the given "table_key" as its one of input,
   // we remove the mapping between the table_key -> hashed_query_plan_dag
   // since we do not need to care about "already marked" item in the cache
   removeTableKeyInfoFromQueryPlanDagMap(table_key);
 
   // hash tables built from synthetically generated tables have no chance to be cleared
   // since we assume their table keys as {-1, -1}
   // this means that typically we do not have a chance to invalidate cached items
   // by calling invalidation request with table key {-1, -1}
   // thus, we manually invalidate them here to maintain cache space based on the
   // assumption that synthetically generated table is not frequently used as typical
   // tables do
   removeCachedHashtableBuiltFromSyntheticTable(item_type, device_identifier, lock);
 }

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void HashtableRecycler::putItemToCache	(	QueryPlanHash	key,
		std::shared_ptr< HashTable >	item_ptr,
		CacheItemType	item_type,
		DeviceIdentifier	device_identifier,
		size_t	item_size,
		size_t	compute_time,
		std::optional< HashtableCacheMetaInfo >	meta_info = `std::nullopt`
	)

overridevirtual

Implements DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >.

Definition at line 93 of file HashtableRecycler.cpp.

References AVAILABLE_AFTER_CLEANUP, CHECK, CHECK_EQ, checkOverlapsHashtableBucketCompatability(), cleanupCacheForInsertion(), EMPTY_HASHED_PLAN_DAG_KEY, g_enable_data_recycler, g_use_hashtable_cache, DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getCachedItemContainer(), DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getCacheLock(), DataRecyclerUtil::getDeviceIdentifierString(), DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getMetricTracker(), hasItemInCache(), OVERLAPS_HT, removeItemFromCache(), UNAVAILABLE, and VLOG.

                                                                                       {
   if (!g_enable_data_recycler || !g_use_hashtable_cache ||
       key == EMPTY_HASHED_PLAN_DAG_KEY) {
     return;
   }
   std::lock_guard<std::mutex> lock(getCacheLock());
   auto has_cached_ht = hasItemInCache(key, item_type, device_identifier, lock, meta_info);
   if (has_cached_ht) {
     // check to see whether the cached one is in a dirty status
     auto hashtable_cache = getCachedItemContainer(item_type, device_identifier);
     auto candidate_it =
         std::find_if(hashtable_cache->begin(),
                      hashtable_cache->end(),
                      [&key](const auto& cached_item) { return cached_item.key == key; });
     bool found_candidate = false;
     if (candidate_it != hashtable_cache->end()) {
       if (item_type == OVERLAPS_HT) {
         // we have to check hashtable metainfo for overlaps join hashtable
         CHECK(candidate_it->meta_info && candidate_it->meta_info->overlaps_meta_info);
         CHECK(meta_info && meta_info->overlaps_meta_info);
         if (checkOverlapsHashtableBucketCompatability(
                 *candidate_it->meta_info->overlaps_meta_info,
                 *meta_info->overlaps_meta_info)) {
           found_candidate = true;
         }
       } else {
         found_candidate = true;
       }
       if (found_candidate && candidate_it->isDirty()) {
         // remove the dirty item from the cache and make a room for the new one
         removeItemFromCache(
             key, item_type, device_identifier, lock, candidate_it->meta_info);
         has_cached_ht = false;
       }
     }
   }
 
   if (!has_cached_ht) {
     // check cache's space availability
     auto& metric_tracker = getMetricTracker(item_type);
     auto cache_status = metric_tracker.canAddItem(device_identifier, item_size);
     if (cache_status == CacheAvailability::UNAVAILABLE) {
       // hashtable is too large
       return;
     } else if (cache_status == CacheAvailability::AVAILABLE_AFTER_CLEANUP) {
       // we need to cleanup some cached hashtables to make a room to insert this hashtable
       // here we try to cache the new one anyway since we don't know the importance of
       // this hashtable yet and if it is not that frequently reused it is removed
       // in a near future
       auto required_size = metric_tracker.calculateRequiredSpaceForItemAddition(
           device_identifier, item_size);
       cleanupCacheForInsertion(item_type, device_identifier, required_size, lock);
     }
     // put hashtable's metric to metric tracker
     auto new_cache_metric_ptr = metric_tracker.putNewCacheItemMetric(
         key, device_identifier, item_size, compute_time);
     CHECK_EQ(item_size, new_cache_metric_ptr->getMemSize());
     // put hashtable to cache
     VLOG(1) << "[" << item_type << ", "
             << DataRecyclerUtil::getDeviceIdentifierString(device_identifier)
             << "] Put item to cache (key: " << key << ")";
     auto hashtable_cache = getCachedItemContainer(item_type, device_identifier);
     hashtable_cache->emplace_back(key, item_ptr, new_cache_metric_ptr, meta_info);
   }
   // we have a cached hashtable in a clean status
   return;
 }

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void HashtableRecycler::removeCachedHashtableBuiltFromSyntheticTable	(	CacheItemType	item_type,
		DeviceIdentifier	device_identifier,
		std::lock_guard< std::mutex > &	lock
	)

private

Definition at line 288 of file HashtableRecycler.cpp.

References CHECK, DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getCachedItemContainer(), DataRecyclerUtil::getUnitaryTableKey(), removeItemFromCache(), removeTableKeyInfoFromQueryPlanDagMap(), and table_key_to_query_plan_dag_map_.

Referenced by markCachedItemAsDirty().

                                    {
   auto hashtable_cache = getCachedItemContainer(item_type, device_identifier);
   CHECK(hashtable_cache);
   auto unitary_table_key = DataRecyclerUtil::getUnitaryTableKey();
   auto key_set_it = table_key_to_query_plan_dag_map_.find(unitary_table_key);
   if (key_set_it != table_key_to_query_plan_dag_map_.end()) {
     auto& key_set = key_set_it->second;
     for (auto key : key_set) {
       removeItemFromCache(key, item_type, device_identifier, lock);
     }
     // after marking all cached hashtable having the given "table_key" as its one of
     // input, we remove the mapping between the table_key -> hashed_query_plan_dag since
     // we do not need to care about "already marked" item in the cache
     removeTableKeyInfoFromQueryPlanDagMap(unitary_table_key);
   }
 }

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void HashtableRecycler::removeItemFromCache	(	QueryPlanHash	key,
		CacheItemType	item_type,
		DeviceIdentifier	device_identifier,
		std::lock_guard< std::mutex > &	lock,
		std::optional< HashtableCacheMetaInfo >	meta_info = `std::nullopt`
	)

overrideprivatevirtual

Implements DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >.

Definition at line 167 of file HashtableRecycler.cpp.

References CHECK, EMPTY_HASHED_PLAN_DAG_KEY, g_enable_data_recycler, g_use_hashtable_cache, DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getCachedItemContainer(), DataRecyclerUtil::getDeviceIdentifierString(), DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getMetricTracker(), REMOVE, and VLOG.

Referenced by putItemToCache(), and removeCachedHashtableBuiltFromSyntheticTable().

                                                    {
   if (!g_enable_data_recycler || !g_use_hashtable_cache ||
       key == EMPTY_HASHED_PLAN_DAG_KEY) {
     return;
   }
   auto& cache_metrics = getMetricTracker(item_type);
   // remove cached item from the cache
   auto cache_metric = cache_metrics.getCacheItemMetric(key, device_identifier);
   CHECK(cache_metric);
   auto hashtable_size = cache_metric->getMemSize();
   auto hashtable_container = getCachedItemContainer(item_type, device_identifier);
   auto filter = [key](auto const& item) { return item.key == key; };
   auto itr =
       std::find_if(hashtable_container->cbegin(), hashtable_container->cend(), filter);
   if (itr == hashtable_container->cend()) {
     return;
   } else {
     VLOG(1) << "[" << item_type << ", "
             << DataRecyclerUtil::getDeviceIdentifierString(device_identifier)
             << "] remove cached item from cache (key: " << key << ")";
     hashtable_container->erase(itr);
   }
   // remove cache metric
   cache_metrics.removeCacheItemMetric(key, device_identifier);
   // update current cache size
   cache_metrics.updateCurrentCacheSize(
       device_identifier, CacheUpdateAction::REMOVE, hashtable_size);
   return;
 }

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void HashtableRecycler::removeTableKeyInfoFromQueryPlanDagMap ( size_t table_key )

Definition at line 526 of file HashtableRecycler.cpp.

References table_key_to_query_plan_dag_map_.

Referenced by markCachedItemAsDirty(), and removeCachedHashtableBuiltFromSyntheticTable().

                                                                               {
   // this function is called when marking cached item for the given table_key as dirty
   // and when we do that we already acquire the cache lock so we skip to lock in this func
   table_key_to_query_plan_dag_map_.erase(table_key);
 }

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std::string HashtableRecycler::toString ( ) const

overridevirtual

Implements DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >.

Definition at line 308 of file HashtableRecycler.cpp.

References DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getCacheItemType(), DataRecyclerUtil::getDeviceIdentifierString(), DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getItemCache(), and DataRecycler< std::shared_ptr< HashTable >, HashtableCacheMetaInfo >::getMetricTracker().

Referenced by getHashtableAccessPathInfo().

                                             {
   std::ostringstream oss;
   oss << "A current status of the Hashtable Recycler:\n";
   for (auto& item_type : getCacheItemType()) {
     oss << "\t" << item_type;
     auto& metric_tracker = getMetricTracker(item_type);
     oss << "\n\t# cached hashtables:\n";
     auto item_cache = getItemCache().find(item_type)->second;
     for (auto& cache_container : *item_cache) {
       oss << "\t\tDevice"
           << DataRecyclerUtil::getDeviceIdentifierString(cache_container.first)
           << ", # hashtables: " << cache_container.second->size() << "\n";
       for (auto& ht : *cache_container.second) {
         oss << "\t\t\tHT] " << ht.item_metric->toString() << "\n";
       }
     }
     oss << "\t" << metric_tracker.toString() << "\n";
   }
   return oss.str();
 }

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Member Data Documentation

HashtableRecycler::g_hashtable_cache_total_bytes

Definition at line 57 of file HashtableRecycler.h.

HashtableRecycler::g_max_cacheable_hashtable_size_bytes

Definition at line 57 of file HashtableRecycler.h.

HashtableRecycler::num_gpus

Initial value:

{}
  std::shared_ptr<HashTable> getItemFromCache(
      QueryPlanHash key,
      CacheItemType item_type,
      DeviceIdentifier device_identifier,
      std::optional<HashtableCacheMetaInfo> meta_info = std::nullopt) override

Definition at line 60 of file HashtableRecycler.h.

std::unordered_map<size_t, std::unordered_set<size_t> > HashtableRecycler::table_key_to_query_plan_dag_map_

private

Definition at line 173 of file HashtableRecycler.h.

Referenced by addQueryPlanDagForTableKeys(), clearCache(), getMappedQueryPlanDagsWithTableKey(), removeCachedHashtableBuiltFromSyntheticTable(), and removeTableKeyInfoFromQueryPlanDagMap().

The documentation for this class was generated from the following files:

/home/jenkins-slave/workspace/core-os-doxygen/QueryEngine/DataRecycler/HashtableRecycler.h
/home/jenkins-slave/workspace/core-os-doxygen/QueryEngine/DataRecycler/HashtableRecycler.cpp

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