org.apache.cassandra.db

Class Directories

java.lang.Object

org.apache.cassandra.db.Directories

public class Directories
extends java.lang.Object

Encapsulate handling of paths to the data files. The directory layout is the following: //ks/cf1/ks-cf1-hb-1-Data.db /cf2/ks-cf2-hb-1-Data.db ... In addition, more that one 'root' data directory can be specified so that potentially represents multiple locations. Note that in the case of multiple locations, the manifest for the leveled compaction is only in one of the location. Snapshots (resp. backups) are always created along the sstables thare are snapshoted (resp. backuped) but inside a subdirectory named 'snapshots' (resp. backups) (and snapshots are furter inside a subdirectory of the name of the snapshot). This class abstracts all those details from the rest of the code.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Directories.DataDirectory
class	Directories.SSTableLister

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	BACKUPS_SUBDIR
static Directories.DataDirectory[]	dataFileLocations
static java.lang.String	SECONDARY_INDEX_NAME_SEPARATOR
static java.lang.String	SNAPSHOT_SUBDIR

Method Summary

Methods

Modifier and Type	Method and Description
void	clearSnapshot(java.lang.String snapshotName)
static Directories	create(java.lang.String tablename, java.lang.String cfname)
static java.io.File	getBackupsDirectory(Descriptor desc)
java.io.File	getDirectoryForNewSSTables(long estimatedSize)
Directories.DataDirectory	getLocationCapableOfSize(long estimatedSize) Finds location which is capable of holding given estimatedSize.
java.io.File	getLocationForDisk(Directories.DataDirectory dataDirectory) Returns SSTable location which is inside given data directory.
java.io.File	getLocationWithMaximumAvailableSpace(long estimatedSize)
java.io.File	getOrCreateLeveledManifest()
static java.io.File	getSnapshotDirectory(Descriptor desc, java.lang.String snapshotName)
static void	migrateSSTables() Move sstables from the pre-#2749 layout to their new location/names.
long	snapshotCreationTime(java.lang.String snapshotName)
boolean	snapshotExists(java.lang.String snapshotName)
void	snapshotLeveledManifest(java.lang.String snapshotName)
Directories.SSTableLister	sstableLister()
static boolean	sstablesNeedsMigration() To check if sstables needs migration, we look at the System directory.
java.io.File	tryGetLeveledManifest()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

BACKUPS_SUBDIR

public static final java.lang.String BACKUPS_SUBDIR

See Also:

Constant Field Values

SNAPSHOT_SUBDIR

public static final java.lang.String SNAPSHOT_SUBDIR

See Also:

Constant Field Values

SECONDARY_INDEX_NAME_SEPARATOR

public static final java.lang.String SECONDARY_INDEX_NAME_SEPARATOR

See Also:

Constant Field Values

dataFileLocations

public static final Directories.DataDirectory[] dataFileLocations

Method Detail

create

public static Directories create(java.lang.String tablename,
                 java.lang.String cfname)

getLocationForDisk

public java.io.File getLocationForDisk(Directories.DataDirectory dataDirectory)

Returns SSTable location which is inside given data directory.

Parameters:

dataDirectory -

Returns:

SSTable location

getDirectoryForNewSSTables

public java.io.File getDirectoryForNewSSTables(long estimatedSize)

getLocationWithMaximumAvailableSpace

public java.io.File getLocationWithMaximumAvailableSpace(long estimatedSize)

getLocationCapableOfSize

public Directories.DataDirectory getLocationCapableOfSize(long estimatedSize)

Finds location which is capable of holding given estimatedSize. Picks a non-blacklisted directory with most free space and least current tasks. If no directory can hold given estimatedSize, then returns null.

Parameters:

estimatedSize - estimated size you need to find location to fit

Returns:

directory capable of given estimated size, or null if none found

getSnapshotDirectory

public static java.io.File getSnapshotDirectory(Descriptor desc,
                                java.lang.String snapshotName)

getBackupsDirectory

public static java.io.File getBackupsDirectory(Descriptor desc)

sstableLister

public Directories.SSTableLister sstableLister()

tryGetLeveledManifest

public java.io.File tryGetLeveledManifest()

getOrCreateLeveledManifest

public java.io.File getOrCreateLeveledManifest()

snapshotLeveledManifest

public void snapshotLeveledManifest(java.lang.String snapshotName)

snapshotExists

public boolean snapshotExists(java.lang.String snapshotName)

clearSnapshot

public void clearSnapshot(java.lang.String snapshotName)

snapshotCreationTime

public long snapshotCreationTime(java.lang.String snapshotName)

sstablesNeedsMigration

public static boolean sstablesNeedsMigration()

To check if sstables needs migration, we look at the System directory. If it does not contain a directory for the schema cfs, we'll attempt a sstable migration. Note that it is mostly harmless to try a migration uselessly, except maybe for some wasted cpu cycles.

migrateSSTables

public static void migrateSSTables()

Move sstables from the pre-#2749 layout to their new location/names. This involves: - moving each sstable to their CF specific directory - rename the sstable to include the keyspace in the filename Note that this also move leveled manifests, snapshots and backups.