Metadata of a masstree storage. More...

Detailed Description

Metadata of a masstree storage.

Definition at line 41 of file masstree_metadata.hpp.

#include <masstree_metadata.hpp>

Inheritance diagram for foedus::storage::masstree::MasstreeMetadata:

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Collaboration diagram for foedus::storage::masstree::MasstreeMetadata:

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Public Types
enum	Constants { kDefaultDropVolatilePagesBtreeLevels = 3 }

Public Member Functions
	MasstreeMetadata ()

	MasstreeMetadata (StorageId id, const StorageName &name, uint16_t border_early_split_threshold=0, uint16_t snapshot_drop_volatile_pages_layer_threshold=0, uint16_t snapshot_drop_volatile_pages_btree_levels=kDefaultDropVolatilePagesBtreeLevels, Layer min_layer_hint=0)

	MasstreeMetadata (const StorageName &name, uint16_t border_early_split_threshold=0, uint16_t snapshot_drop_volatile_pages_layer_threshold=0, uint16_t snapshot_drop_volatile_pages_btree_levels=kDefaultDropVolatilePagesBtreeLevels, Layer min_layer_hint=0)
	This one is for newly creating a storage. More...

std::string	describe () const

bool	should_aggresively_create_next_layer (Layer cur_layer, KeyLength remainder) const

Public Member Functions inherited from foedus::storage::Metadata
	Metadata ()

	Metadata (StorageId id, StorageType type, const StorageName &name)

	Metadata (StorageId id, StorageType type, const StorageName &name, SnapshotPagePointer root_snapshot_page_id)

bool	keeps_all_volatile_pages () const

Public Attributes
uint16_t	border_early_split_threshold_
	Kind of fill factor for border pages, bit different from usual B-tree. More...

uint16_t	snapshot_drop_volatile_pages_layer_threshold_
	Number of B-trie layers of volatile pages to keep after each snapshotting. More...

uint16_t	snapshot_drop_volatile_pages_btree_levels_
	Volatile pages of this B-tree level or higher are always kept after each snapshotting. More...

Layer	min_layer_hint_
	Hints how many layers this storage will create for most of records. More...

uint8_t	pad1_

Public Attributes inherited from foedus::storage::Metadata
StorageId	id_
	the unique ID of this storage. More...

StorageType	type_
	type of the storage. More...

StorageName	name_
	the unique name of this storage. More...

SnapshotPagePointer	root_snapshot_page_id_
	Pointer to a snapshotted page this storage is rooted at. More...

SnapshotThresholds	snapshot_thresholds_

Friends
std::ostream &	operator<< (std::ostream &o, const MasstreeMetadata &v)

Additional Inherited Members
Static Public Member Functions inherited from foedus::storage::Metadata
static std::string	describe (const Metadata &metadata)
	to_string operator of all Metadata objects. More...

Member Enumeration Documentation

enum foedus::storage::masstree::MasstreeMetadata::Constants

Enumerator
kDefaultDropVolatilePagesBtreeLevels

Definition at line 42 of file masstree_metadata.hpp.

                  {
     kDefaultDropVolatilePagesBtreeLevels = 3,
   };

Constructor & Destructor Documentation

foedus::storage::masstree::MasstreeMetadata::MasstreeMetadata ( )

inline

Definition at line 45 of file masstree_metadata.hpp.

                      :
     Metadata(0, kMasstreeStorage, ""),
     border_early_split_threshold_(0),
     snapshot_drop_volatile_pages_layer_threshold_(0),
     snapshot_drop_volatile_pages_btree_levels_(kDefaultDropVolatilePagesBtreeLevels),
     min_layer_hint_(0),
     pad1_(0) {}

foedus::storage::masstree::MasstreeMetadata::MasstreeMetadata	(	StorageId	id,
		const StorageName &	name,
		uint16_t	border_early_split_threshold = `0`,
		uint16_t	snapshot_drop_volatile_pages_layer_threshold = `0`,
		uint16_t	snapshot_drop_volatile_pages_btree_levels = `kDefaultDropVolatilePagesBtreeLevels`,
		Layer	min_layer_hint = `0`
	)

inline

Definition at line 52 of file masstree_metadata.hpp.

     : Metadata(id, kMasstreeStorage, name),
       border_early_split_threshold_(border_early_split_threshold),
       snapshot_drop_volatile_pages_layer_threshold_(snapshot_drop_volatile_pages_layer_threshold),
       snapshot_drop_volatile_pages_btree_levels_(snapshot_drop_volatile_pages_btree_levels),
       min_layer_hint_(min_layer_hint),
       pad1_(0) {
   }

foedus::storage::masstree::MasstreeMetadata::MasstreeMetadata	(	const StorageName &	name,
		uint16_t	border_early_split_threshold = `0`,
		uint16_t	snapshot_drop_volatile_pages_layer_threshold = `0`,
		uint16_t	snapshot_drop_volatile_pages_btree_levels = `kDefaultDropVolatilePagesBtreeLevels`,
		Layer	min_layer_hint = `0`
	)

inline

This one is for newly creating a storage.

Definition at line 67 of file masstree_metadata.hpp.

     : Metadata(0, kMasstreeStorage, name),
       border_early_split_threshold_(border_early_split_threshold),
       snapshot_drop_volatile_pages_layer_threshold_(snapshot_drop_volatile_pages_layer_threshold),
       snapshot_drop_volatile_pages_btree_levels_(snapshot_drop_volatile_pages_btree_levels),
       min_layer_hint_(min_layer_hint),
       pad1_(0) {
   }

Member Function Documentation

std::string foedus::storage::masstree::MasstreeMetadata::describe ( ) const

Definition at line 29 of file masstree_metadata.cpp.

                                            {
   std::stringstream o;
   o << MasstreeMetadataSerializer(const_cast<MasstreeMetadata*>(this));
   return o.str();
 }

bool foedus::storage::masstree::MasstreeMetadata::should_aggresively_create_next_layer	(	Layer	cur_layer,
		KeyLength	remainder
	)		const

inline

Returns: whether we should create a next layer based on min_layer_hint_

Definition at line 132 of file masstree_metadata.hpp.

                                                                                            {
     if (remainder <= sizeof(KeySlice)) {
       return false;  // anyway can't create a next layer.
     }
     return min_layer_hint_ > cur_layer;
   }

Friends And Related Function Documentation

std::ostream& operator<<	(	std::ostream &	o,
		const MasstreeMetadata &	v
	)

friend

Definition at line 34 of file masstree_metadata.cpp.

                                                                  {
   o << MasstreeMetadataSerializer(const_cast<MasstreeMetadata*>(&v));
   return o;
 }

Member Data Documentation

uint16_t foedus::storage::masstree::MasstreeMetadata::border_early_split_threshold_

Kind of fill factor for border pages, bit different from usual B-tree.

Border pages split without being full when a border page seems to receive sequential inserts and the physical key count will exactly hit this value. Once it passes this value, it goes on until it really becomes full (otherwise there is no point.. the border pages keep splitting without necessity). When the page is not receiving sequential inserts, there are also no points to split early. The default is 0, which means we never consider early split.

Definition at line 94 of file masstree_metadata.hpp.

Referenced by foedus::storage::masstree::MasstreeMetadataSerializer::load(), and foedus::storage::masstree::MasstreeMetadataSerializer::save().

Layer foedus::storage::masstree::MasstreeMetadata::min_layer_hint_

Hints how many layers this storage will create for most of records.

0 is the default, which does nothing. n (n>0) hints that most records in this storage will be stored in layer-n or deeper, thus we should blindly create an initially next-layer record in layer-(n-1) and above as far as the length of the key allows.

If appropriately specified, this reduces contention and wasted space in layer-(n-1) and above. If you specify too large min_layer_hint_, it might slow down searches because the record could otherwise fit in layer-(n-1) or above.

Definition at line 126 of file masstree_metadata.hpp.

Referenced by foedus::storage::masstree::MasstreeMetadataSerializer::load(), and foedus::storage::masstree::MasstreeMetadataSerializer::save().

uint8_t foedus::storage::masstree::MasstreeMetadata::pad1_

Definition at line 129 of file masstree_metadata.hpp.

uint16_t foedus::storage::masstree::MasstreeMetadata::snapshot_drop_volatile_pages_btree_levels_

Volatile pages of this B-tree level or higher are always kept after each snapshotting.

0 means we don't drop any volatile pages. 1 means we drop only border pages. Note that this and snapshot_drop_volatile_pages_layer_threshold_ are AND conditions, meaning we drop volatile pages that meet both conditions. Further, we anyway don't drop volatile pages that have modifications after the snapshot epoch. The default is kDefaultDropVolatilePagesBtreeLevels.

Definition at line 112 of file masstree_metadata.hpp.

Referenced by foedus::storage::masstree::MasstreeMetadataSerializer::load(), and foedus::storage::masstree::MasstreeMetadataSerializer::save().

uint16_t foedus::storage::masstree::MasstreeMetadata::snapshot_drop_volatile_pages_layer_threshold_

Number of B-trie layers of volatile pages to keep after each snapshotting.

0 means this storage drops volatile pages even if it's in the first layer. 1 means it keeps all pages in first layer. The default is 0.

Definition at line 102 of file masstree_metadata.hpp.

Referenced by foedus::storage::masstree::MasstreeMetadataSerializer::load(), and foedus::storage::masstree::MasstreeMetadataSerializer::save().

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

/home/shino/foedus_code/foedus-core/include/foedus/storage/masstree/masstree_metadata.hpp
/home/shino/foedus_code/foedus-core/src/foedus/storage/masstree/masstree_metadata.cpp

Detailed Description

Public Types

Public Member Functions

Public Attributes

Friends

Additional Inherited Members

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation

Member Data Documentation