duckdb::WriteAheadLog Class Reference

Collaboration diagram for duckdb::WriteAheadLog:

Public Member Functions
	WriteAheadLog (StorageManager &storage_manager, const string &wal_path, idx_t wal_size=0ULL, WALInitState state=WALInitState::NO_WAL, optional_idx checkpoint_iteration=optional_idx())
	Initialize the WAL in the specified directory.
AttachedDatabase &	GetDatabase ()
StorageManager &	GetStorageManager ()
const string &	GetPath () const
idx_t	GetTotalWritten () const
	Gets the total bytes written to the WAL since startup.
bool	Initialized () const
	A WAL is initialized, if a writer to a file exists.
BufferedFileWriter &	Initialize ()
	Initializes the file of the WAL by creating the file writer.
void	WriteHeader ()
	Write the WAL header.
virtual void	WriteCreateTable (const TableCatalogEntry &entry)
void	WriteDropTable (const TableCatalogEntry &entry)
void	WriteCreateSchema (const SchemaCatalogEntry &entry)
void	WriteDropSchema (const SchemaCatalogEntry &entry)
void	WriteCreateView (const ViewCatalogEntry &entry)
void	WriteDropView (const ViewCatalogEntry &entry)
void	WriteCreateSequence (const SequenceCatalogEntry &entry)
void	WriteDropSequence (const SequenceCatalogEntry &entry)
void	WriteSequenceValue (SequenceValue val)
void	WriteCreateMacro (const ScalarMacroCatalogEntry &entry)
void	WriteDropMacro (const ScalarMacroCatalogEntry &entry)
void	WriteCreateTableMacro (const TableMacroCatalogEntry &entry)
void	WriteDropTableMacro (const TableMacroCatalogEntry &entry)
void	WriteCreateIndex (const IndexCatalogEntry &entry)
void	WriteDropIndex (const IndexCatalogEntry &entry)
void	WriteCreateType (const TypeCatalogEntry &entry)
void	WriteDropType (const TypeCatalogEntry &entry)
void	WriteSetTable (const string &schema, const string &table)
	Sets the table used for subsequent insert/delete/update commands.
void	WriteAlter (CatalogEntry &entry, const AlterInfo &info)
void	WriteInsert (DataChunk &chunk)
void	WriteRowGroupData (const PersistentCollectionData &data)
void	WriteDelete (DataChunk &chunk)
void	WriteUpdate (DataChunk &chunk, const vector< column_t > &column_path)
void	Truncate (idx_t size)
void	Flush ()
void	IncrementWALEntriesCount ()
	Increment the WAL entry count, which is used for the auto-checkpoint threshold.
void	WriteCheckpoint (MetaBlockPointer meta_block)

Static Public Member Functions
static unique_ptr< WriteAheadLog >	Replay (QueryContext context, StorageManager &storage_manager, const string &wal_path)
	Replay and initialize the WAL, QueryContext is passed for metric collection purposes only!!

Protected Attributes
StorageManager &	storage_manager
mutex	wal_lock
unique_ptr< BufferedFileWriter >	writer
string	wal_path
atomic< WALInitState >	init_state
optional_idx	checkpoint_iteration

Detailed Description

The WriteAheadLog (WAL) is a log that is used to provide durability. Prior to committing a transaction it writes the changes the transaction made to the database to the log, which can then be replayed upon startup in case the server crashes or is shut down.

Member Function Documentation

GetPath()

const string & duckdb::WriteAheadLog::GetPath ( ) const

inline

                                  {
        return wal_path;
    }

WriteUpdate()

void duckdb::WriteAheadLog::WriteUpdate	(	DataChunk &	chunk,
		const vector< column_t > &	column_path
	)

Write a single (sub-) column update to the WAL. Chunk must be a pair of (COL, ROW_ID). The column_path vector is a path towards a column within the table i.e. if we have a table with a single column S STRUCT(A INT, B INT) and we update the validity mask of "S.B" the column path is: 0 (first column of table) -> 1 (second subcolumn of struct) -> 0 (first subcolumn of INT)

Truncate()

void duckdb::WriteAheadLog::Truncate

(

idx_t

size

)

Truncate the WAL to a previous size, and clear anything currently set in the writer. Used during RevertCommit.

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

• external/duckdb/duckdb.cpp