The information we maintain in savepoint manager and externalize to a file. More...

Detailed Description

The information we maintain in savepoint manager and externalize to a file.

This object is a very compact representation of progress of the entire engine. This object holds only a few integers per module to denote upto what we are surely done. We update this object for each epoch-based group commit and write out this as an xml durably and atomically.

Definition at line 40 of file savepoint.hpp.

#include <savepoint.hpp>

Inheritance diagram for foedus::savepoint::Savepoint:

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Collaboration diagram for foedus::savepoint::Savepoint:

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Public Member Functions
	Savepoint ()
	Constructs an empty savepoint. More...

ErrorStack	load (tinyxml2::XMLElement *element) override
	Reads the content of this object from the given XML element. More...

ErrorStack	save (tinyxml2::XMLElement *element) const override
	Writes the content of this object to the given XML element. More...

const char *	get_tag_name () const override
	Returns an XML tag name for this object as a root element. More...

void	assign (const foedus::externalize::Externalizable *other) override
	Polymorphic assign operator. More...

void	populate_empty (log::LoggerId logger_count)
	Populate variables as an initial state. More...

bool	consistent (log::LoggerId logger_count) const
	Tells if the variables are consistent. More...

Epoch	get_durable_epoch () const

Epoch	get_current_epoch () const

Epoch	get_earliest_epoch () const

void	assert_epoch_values () const
	Check invariants on current_epoch_/durable_epoch_. More...

Public Member Functions inherited from foedus::externalize::Externalizable
ErrorStack	load_from_string (const std::string &xml)
	Load the content of this object from the given XML string. More...

void	save_to_stream (std::ostream *ptr) const
	Invokes save() and directs the resulting XML text to the given stream. More...

ErrorStack	load_from_file (const fs::Path &path)
	Load the content of this object from the specified XML file. More...

ErrorStack	save_to_file (const fs::Path &path) const
	Atomically and durably writes out this object to the specified XML file. More...

Public Attributes
Epoch::EpochInteger	current_epoch_
	Current epoch of the entire engine. More...

Epoch::EpochInteger	durable_epoch_
	Latest epoch whose logs were all flushed to disk. More...

Epoch::EpochInteger	earliest_epoch_
	The earliest epoch that can exist in this system. More...

snapshot::SnapshotId	latest_snapshot_id_
	The most recent complete snapshot. More...

Epoch::EpochInteger	latest_snapshot_epoch_
	The most recently snapshot-ed epoch, all logs upto this epoch is safe to delete. More...

uint64_t	meta_log_oldest_offset_
	Offset from which metadata log entries are not gleaned yet. More...

uint64_t	meta_log_durable_offset_
	Offset upto which metadata log entries are fsynced. More...

std::vector< log::LogFileOrdinal >	oldest_log_files_
	Ordinal of the oldest active log file in each logger. More...

std::vector< uint64_t >	oldest_log_files_offset_begin_
	Indicates the inclusive beginning of active region in the oldest log file. More...

std::vector< log::LogFileOrdinal >	current_log_files_
	Indicates the log file each logger is currently appending to. More...

std::vector< uint64_t >	current_log_files_offset_durable_
	Indicates the exclusive end of durable region in the current log file. More...

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

Additional Inherited Members
Static Public Member Functions inherited from foedus::externalize::Externalizable
static ErrorStack	insert_comment (tinyxml2::XMLElement *element, const std::string &comment)

static ErrorStack	append_comment (tinyxml2::XMLElement *parent, const std::string &comment)

static ErrorStack	create_element (tinyxml2::XMLElement parent, const std::string &name, tinyxml2::XMLElement *out)

template<typename T >
static ErrorStack	add_element (tinyxml2::XMLElement *parent, const std::string &tag, const std::string &comment, T value)
	Only declaration in header. More...

template<uint MAXLEN, typename CHAR >
static ErrorStack	add_element (tinyxml2::XMLElement *parent, const std::string &tag, const std::string &comment, const assorted::FixedString< MAXLEN, CHAR > &value)

template<typename T >
static ErrorStack	add_element (tinyxml2::XMLElement *parent, const std::string &tag, const std::string &comment, const std::vector< T > &value)
	vector version More...

template<typename ENUM >
static ErrorStack	add_enum_element (tinyxml2::XMLElement *parent, const std::string &tag, const std::string &comment, ENUM value)
	enum version More...

static ErrorStack	add_child_element (tinyxml2::XMLElement *parent, const std::string &tag, const std::string &comment, const Externalizable &child)
	child Externalizable version More...

template<typename T >
static ErrorStack	get_element (tinyxml2::XMLElement parent, const std::string &tag, T out, bool optional=false, T value=0)
	Only declaration in header. More...

static ErrorStack	get_element (tinyxml2::XMLElement parent, const std::string &tag, std::string out, bool optional=false, const char *value="")
	string type is bit special. More...

template<uint MAXLEN, typename CHAR >
static ErrorStack	get_element (tinyxml2::XMLElement parent, const std::string &tag, assorted::FixedString< MAXLEN, CHAR > out, bool optional=false, const assorted::FixedString< MAXLEN, CHAR > &value=assorted::FixedString< MAXLEN, CHAR >())

template<typename ENUM >
static ErrorStack	get_enum_element (tinyxml2::XMLElement parent, const std::string &tag, ENUM out, bool optional=false, ENUM default_value=static_cast< ENUM >(0))
	enum version More...

template<typename T >
static ErrorStack	get_element (tinyxml2::XMLElement parent, const std::string &tag, std::vector< T > out, bool optional=false)
	vector version. More...

static ErrorStack	get_child_element (tinyxml2::XMLElement parent, const std::string &tag, Externalizable child, bool optional=false)
	child Externalizable version More...

Constructor & Destructor Documentation

foedus::savepoint::Savepoint::Savepoint ( )

Constructs an empty savepoint.

Definition at line 22 of file savepoint.cpp.

22 {

23 }

Member Function Documentation

void foedus::savepoint::Savepoint::assert_epoch_values ( ) const

Check invariants on current_epoch_/durable_epoch_.

Definition at line 25 of file savepoint.cpp.

References ASSERT_ND, current_epoch_, durable_epoch_, earliest_epoch_, and latest_snapshot_epoch_.

Referenced by consistent(), load(), populate_empty(), save(), and foedus::savepoint::SavepointManagerPimpl::savepoint_main().

                                           {
   ASSERT_ND(Epoch(current_epoch_).is_valid());
   ASSERT_ND(Epoch(durable_epoch_).is_valid());
   ASSERT_ND(Epoch(earliest_epoch_).is_valid());
   ASSERT_ND(Epoch(current_epoch_) > Epoch(durable_epoch_));
   ASSERT_ND(Epoch(current_epoch_) >= Epoch(earliest_epoch_));
   ASSERT_ND(Epoch(durable_epoch_) >= Epoch(earliest_epoch_));
   ASSERT_ND(!Epoch(latest_snapshot_epoch_).is_valid() ||
     Epoch(latest_snapshot_epoch_) <= Epoch(durable_epoch_));
 }

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void foedus::savepoint::Savepoint::assign ( const foedus::externalize::Externalizable * other )

inlineoverridevirtual

Polymorphic assign operator.

This should invoke operator= of the derived class.

Parameters

[in] other assigned value. It must be dynamic-castable to the assignee class.

Implements foedus::externalize::Externalizable.

Definition at line 116 of file savepoint.hpp.

bool foedus::savepoint::Savepoint::consistent ( log::LoggerId logger_count ) const

inline

Tells if the variables are consistent.

Definition at line 121 of file savepoint.hpp.

References assert_epoch_values().

Referenced by foedus::savepoint::SavepointManagerPimpl::initialize_once().

                                                                                  {
     assert_epoch_values();
     return (current_epoch_ >= durable_epoch_
       && current_epoch_ >= earliest_epoch_
       && durable_epoch_ >= earliest_epoch_
       && meta_log_oldest_offset_ <= meta_log_durable_offset_
       && oldest_log_files_.size() == logger_count
       && oldest_log_files_offset_begin_.size() == logger_count
       && current_log_files_.size() == logger_count
       && current_log_files_offset_durable_.size() == logger_count);
   }

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Epoch foedus::savepoint::Savepoint::get_current_epoch ( ) const

inline

Definition at line 134 of file savepoint.hpp.

134 { return Epoch(current_epoch_); }

foedus::savepoint::Savepoint::current_epoch_

Epoch::EpochInteger current_epoch_

Current epoch of the entire engine.

Definition: savepoint.hpp:53

Epoch foedus::savepoint::Savepoint::get_durable_epoch ( ) const

inline

Definition at line 133 of file savepoint.hpp.

133 { return Epoch(durable_epoch_); }

foedus::savepoint::Savepoint::durable_epoch_

Epoch::EpochInteger durable_epoch_

Latest epoch whose logs were all flushed to disk.

Definition: savepoint.hpp:65

Epoch foedus::savepoint::Savepoint::get_earliest_epoch ( ) const

inline

Definition at line 135 of file savepoint.hpp.

135 { return Epoch(earliest_epoch_); }

foedus::savepoint::Savepoint::earliest_epoch_

Epoch::EpochInteger earliest_epoch_

The earliest epoch that can exist in this system.

Definition: savepoint.hpp:72

const char* foedus::savepoint::Savepoint::get_tag_name ( ) const

inlineoverridevirtual

Returns an XML tag name for this object as a root element.

We might want to give a different name for same externalizable objects, so this is used only when it is the root element of xml.

Implements foedus::externalize::Externalizable.

Definition at line 116 of file savepoint.hpp.

ErrorStack foedus::savepoint::Savepoint::load ( tinyxml2::XMLElement * element )

overridevirtual

Reads the content of this object from the given XML element.

Parameters

[in] element the XML element that represents this object

Expect errors due to missing-elements, out-of-range values, etc.

Implements foedus::externalize::Externalizable.

Definition at line 36 of file savepoint.cpp.

References assert_epoch_values(), current_epoch_, current_log_files_, current_log_files_offset_durable_, durable_epoch_, earliest_epoch_, EXTERNALIZE_LOAD_ELEMENT, foedus::kRetOk, latest_snapshot_epoch_, latest_snapshot_id_, meta_log_durable_offset_, meta_log_oldest_offset_, oldest_log_files_, and oldest_log_files_offset_begin_.

                                                       {
   EXTERNALIZE_LOAD_ELEMENT(element, current_epoch_);
   EXTERNALIZE_LOAD_ELEMENT(element, durable_epoch_);
   EXTERNALIZE_LOAD_ELEMENT(element, earliest_epoch_);
   EXTERNALIZE_LOAD_ELEMENT(element, latest_snapshot_id_);
   EXTERNALIZE_LOAD_ELEMENT(element, latest_snapshot_epoch_);
   EXTERNALIZE_LOAD_ELEMENT(element, meta_log_oldest_offset_);
   EXTERNALIZE_LOAD_ELEMENT(element, meta_log_durable_offset_);
   EXTERNALIZE_LOAD_ELEMENT(element, oldest_log_files_);
   EXTERNALIZE_LOAD_ELEMENT(element, oldest_log_files_offset_begin_);
   EXTERNALIZE_LOAD_ELEMENT(element, current_log_files_);
   EXTERNALIZE_LOAD_ELEMENT(element, current_log_files_offset_durable_);
   assert_epoch_values();
   return kRetOk;
 }

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void foedus::savepoint::Savepoint::populate_empty ( log::LoggerId logger_count )

Populate variables as an initial state.

Definition at line 79 of file savepoint.cpp.

References assert_epoch_values(), current_epoch_, current_log_files_, current_log_files_offset_durable_, durable_epoch_, earliest_epoch_, foedus::Epoch::kEpochInitialCurrent, foedus::Epoch::kEpochInitialDurable, foedus::Epoch::kEpochInvalid, foedus::snapshot::kNullSnapshotId, latest_snapshot_epoch_, latest_snapshot_id_, meta_log_durable_offset_, meta_log_oldest_offset_, oldest_log_files_, and oldest_log_files_offset_begin_.

Referenced by foedus::savepoint::SavepointManagerPimpl::initialize_once().

                                                        {
   current_epoch_ = Epoch::kEpochInitialCurrent;
   durable_epoch_ = Epoch::kEpochInitialDurable;
   earliest_epoch_ = Epoch::kEpochInitialDurable;
   latest_snapshot_id_ = snapshot::kNullSnapshotId;
   latest_snapshot_epoch_ = Epoch::kEpochInvalid;
   meta_log_oldest_offset_ = 0;
   meta_log_durable_offset_ = 0;
   oldest_log_files_.resize(logger_count, 0);
   oldest_log_files_offset_begin_.resize(logger_count, 0);
   current_log_files_.resize(logger_count, 0);
   current_log_files_offset_durable_.resize(logger_count, 0);
   assert_epoch_values();
 }

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ErrorStack foedus::savepoint::Savepoint::save ( tinyxml2::XMLElement * element ) const

overridevirtual

Writes the content of this object to the given XML element.

Parameters

[in] element the XML element that represents this object

Expect only out-of-memory error. We receive the XML element this object will represent, so this method does not determine the XML element name of itself. The parent object determines children's tag names because one parent object might have multiple child objects of the same type with different XML element name.

Implements foedus::externalize::Externalizable.

Definition at line 52 of file savepoint.cpp.

References assert_epoch_values(), CHECK_ERROR, current_epoch_, current_log_files_, current_log_files_offset_durable_, durable_epoch_, earliest_epoch_, EXTERNALIZE_SAVE_ELEMENT, foedus::externalize::Externalizable::insert_comment(), foedus::kRetOk, latest_snapshot_epoch_, latest_snapshot_id_, meta_log_durable_offset_, meta_log_oldest_offset_, oldest_log_files_, and oldest_log_files_offset_begin_.

                                                             {
   assert_epoch_values();
   CHECK_ERROR(insert_comment(element, "progress of the entire engine"));
 
   EXTERNALIZE_SAVE_ELEMENT(element, current_epoch_, "Current epoch of the entire engine.");
   EXTERNALIZE_SAVE_ELEMENT(element, durable_epoch_,
                "Latest epoch whose logs were all flushed to disk");
   EXTERNALIZE_SAVE_ELEMENT(element, earliest_epoch_,
                "The earliest epoch that can exist in this system");
   EXTERNALIZE_SAVE_ELEMENT(element, latest_snapshot_id_, "The most recent complete snapshot.");
   EXTERNALIZE_SAVE_ELEMENT(element, latest_snapshot_epoch_,
               "The most recently snapshot-ed epoch, all logs upto this epoch is safe to delete.");
   EXTERNALIZE_SAVE_ELEMENT(element, meta_log_oldest_offset_,
                "Offset from which metadata log entries are not gleaned yet");
   EXTERNALIZE_SAVE_ELEMENT(element, meta_log_durable_offset_,
                "Offset upto which metadata log entries are fsynced");
   EXTERNALIZE_SAVE_ELEMENT(element, oldest_log_files_,
                "Ordinal of the oldest active log file in each logger");
   EXTERNALIZE_SAVE_ELEMENT(element, oldest_log_files_offset_begin_,
           "Indicates the inclusive beginning of active region in the oldest log file");
   EXTERNALIZE_SAVE_ELEMENT(element, current_log_files_,
                "Indicates the log file each logger is currently appending to");
   EXTERNALIZE_SAVE_ELEMENT(element, current_log_files_offset_durable_,
             "Indicates the exclusive end of durable region in the current log file");
   return kRetOk;
 }

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Friends And Related Function Documentation

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

friend

Definition at line 116 of file savepoint.hpp.

Member Data Documentation

Epoch::EpochInteger foedus::savepoint::Savepoint::current_epoch_

Current epoch of the entire engine.

This value is advanced by transaction manager periodically. This is equal or larger than all other epoch values below.

Invariant: Epoch(current_epoch_).is_valid()

Definition at line 53 of file savepoint.hpp.

Referenced by assert_epoch_values(), foedus::savepoint::SavepointManagerPimpl::initialize_once(), load(), populate_empty(), save(), foedus::savepoint::SavepointManagerPimpl::savepoint_main(), and foedus::savepoint::FixedSavepoint::update().

std::vector<log::LogFileOrdinal> foedus::savepoint::Savepoint::current_log_files_

Indicates the log file each logger is currently appending to.

Definition at line 107 of file savepoint.hpp.

Referenced by foedus::log::LoggerRef::copy_logger_state(), foedus::log::LogManagerPimpl::copy_logger_states(), load(), populate_empty(), save(), and foedus::savepoint::FixedSavepoint::update().

std::vector<uint64_t> foedus::savepoint::Savepoint::current_log_files_offset_durable_

Indicates the exclusive end of durable region in the current log file.

In other words, epochs are larger than durable_epoch_ from this offset. During restart, current log files are truncated to this size to discard incomplete logs.

Definition at line 114 of file savepoint.hpp.

Referenced by foedus::log::LoggerRef::copy_logger_state(), foedus::log::LogManagerPimpl::copy_logger_states(), load(), populate_empty(), save(), and foedus::savepoint::FixedSavepoint::update().

Epoch::EpochInteger foedus::savepoint::Savepoint::durable_epoch_

Latest epoch whose logs were all flushed to disk.

Upto this epoch, we can guarantee durability. In other words, transactions are not deemed as "done" until this value reaches their epoch values issued on commit time. While the engine restarts, all log entries in log files after this epoch are truncated because there might be some logger that did not finish its writing.

Invariant: Epoch(durable_epoch_).is_valid(); Epoch(current_epoch_) > Epoch(durable_epoch_)

Definition at line 65 of file savepoint.hpp.

Referenced by assert_epoch_values(), foedus::savepoint::SavepointManagerPimpl::initialize_once(), load(), populate_empty(), save(), foedus::savepoint::SavepointManagerPimpl::savepoint_main(), and foedus::savepoint::FixedSavepoint::update().

Epoch::EpochInteger foedus::savepoint::Savepoint::earliest_epoch_

The earliest epoch that can exist in this system.

it advances only after we do a system-wide compaction. Otherwise, it's kEpochInitialDurable, which is indeed the earliest until the epoch wraps around.

Definition at line 72 of file savepoint.hpp.

Referenced by assert_epoch_values(), foedus::savepoint::SavepointManagerPimpl::initialize_once(), load(), populate_empty(), save(), foedus::savepoint::SavepointManagerPimpl::savepoint_main(), and foedus::savepoint::FixedSavepoint::update().

Epoch::EpochInteger foedus::savepoint::Savepoint::latest_snapshot_epoch_

The most recently snapshot-ed epoch, all logs upto this epoch is safe to delete.

If not snapshot has been taken, invalid epoch. This is equivalent to snapshots_.back().valid_entil_epoch_ with empty check.

Definition at line 84 of file savepoint.hpp.

Referenced by assert_epoch_values(), load(), populate_empty(), save(), foedus::savepoint::SavepointManagerPimpl::savepoint_main(), and foedus::savepoint::FixedSavepoint::update().

snapshot::SnapshotId foedus::savepoint::Savepoint::latest_snapshot_id_

The most recent complete snapshot.

kNullSnapshotId if no snapshot has been taken yet.

Definition at line 78 of file savepoint.hpp.

Referenced by load(), populate_empty(), save(), foedus::savepoint::SavepointManagerPimpl::savepoint_main(), and foedus::savepoint::FixedSavepoint::update().

uint64_t foedus::savepoint::Savepoint::meta_log_durable_offset_

Offset upto which metadata log entries are fsynced.

Definition at line 89 of file savepoint.hpp.

Referenced by load(), populate_empty(), save(), foedus::savepoint::SavepointManagerPimpl::savepoint_main(), and foedus::savepoint::FixedSavepoint::update().

uint64_t foedus::savepoint::Savepoint::meta_log_oldest_offset_

Offset from which metadata log entries are not gleaned yet.

Definition at line 87 of file savepoint.hpp.

Referenced by load(), populate_empty(), save(), foedus::savepoint::SavepointManagerPimpl::savepoint_main(), and foedus::savepoint::FixedSavepoint::update().

std::vector<log::LogFileOrdinal> foedus::savepoint::Savepoint::oldest_log_files_

Ordinal of the oldest active log file in each logger.

Invariant: oldest_log_files_[x] <= current_log_files_[x]

Each logger writes out files suffixed with ordinal (eg ".0", ".1"...). The older logs files are deactivated and deleted after log gleaner consumes them. This variable indicates the oldest active file for each logger.

Definition at line 101 of file savepoint.hpp.

Referenced by foedus::log::LoggerRef::copy_logger_state(), foedus::log::LogManagerPimpl::copy_logger_states(), load(), populate_empty(), save(), and foedus::savepoint::FixedSavepoint::update().

std::vector<uint64_t> foedus::savepoint::Savepoint::oldest_log_files_offset_begin_

Indicates the inclusive beginning of active region in the oldest log file.

Definition at line 104 of file savepoint.hpp.

Referenced by foedus::log::LoggerRef::copy_logger_state(), foedus::log::LogManagerPimpl::copy_logger_states(), load(), populate_empty(), save(), and foedus::savepoint::FixedSavepoint::update().

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

/home/shino/foedus_code/foedus-core/include/foedus/savepoint/savepoint.hpp
/home/shino/foedus_code/foedus-core/src/foedus/savepoint/savepoint.cpp

Detailed Description

Public Member Functions

Public Attributes

Friends

Additional Inherited Members

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation

Member Data Documentation