org.apache.cassandra.db.migration
Class Migration

java.lang.Object
  org.apache.cassandra.db.migration.Migration

Direct Known Subclasses:

AddColumnFamily, AddKeyspace, DropColumnFamily, DropKeyspace, UpdateColumnFamily, UpdateKeyspace

public abstract class Migration
extends java.lang.Object

A migration represents a single metadata mutation (cf dropped, added, etc.). There are two parts to a migration (think of it as a schema update): 1. data is written to the schema cf (SCHEMA_KEYSPACES_CF). 2. updated models are applied to the cassandra instance. Since all steps are not committed atomically, care should be taken to ensure that a node/cluster is reasonably quiescent with regard to the Keyspace or ColumnFamily whose schema is being modified.

Field Summary

static java.nio.ByteBuffer	LAST_MIGRATION_KEY
protected static org.slf4j.Logger	logger
static java.lang.String	MIGRATIONS_CF
static java.lang.String	NAME_VALIDATOR_REGEX
static java.lang.String	SCHEMA_CF
protected long	timestamp

Method Summary

void	announce() Send schema update (in form of row mutations) to alive nodes in the cluster.
void	apply()
protected abstract void	applyImpl() Class specific apply implementation where schema migration logic should be put
static java.util.UUID	getLastMigrationId() Deprecated.
static boolean	isLegalName(java.lang.String s)
void	passiveAnnounce() Announce new schema version over Gossip

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected static final org.slf4j.Logger logger

NAME_VALIDATOR_REGEX

public static final java.lang.String NAME_VALIDATOR_REGEX

See Also:

Constant Field Values

MIGRATIONS_CF

public static final java.lang.String MIGRATIONS_CF

See Also:

Constant Field Values

SCHEMA_CF

public static final java.lang.String SCHEMA_CF

See Also:

Constant Field Values

LAST_MIGRATION_KEY

public static final java.nio.ByteBuffer LAST_MIGRATION_KEY

timestamp

protected final long timestamp

Method Detail

apply

public final void apply()
                 throws ConfigurationException,
                        java.io.IOException

Throws:

ConfigurationException

java.io.IOException

applyImpl

protected abstract void applyImpl()
                           throws ConfigurationException,
                                  java.io.IOException

Class specific apply implementation where schema migration logic should be put

Throws:

java.io.IOException - on any I/O related error.

ConfigurationException - if there is object misconfiguration.

announce

public final void announce()

Send schema update (in form of row mutations) to alive nodes in the cluster. apply() must be called first.

passiveAnnounce

public final void passiveAnnounce()

Announce new schema version over Gossip

getLastMigrationId

@Deprecated
public static java.util.UUID getLastMigrationId()

Deprecated.

Used only in case node has old style migration schema (newly updated)

Returns:

the UUID identifying version of the last applied migration

isLegalName

public static boolean isLegalName(java.lang.String s)