Package org.apache.hadoop.hbase.client

Class MetaCache

java.lang.Object

org.apache.hadoop.hbase.client.MetaCache

@Private
public class MetaCache
extends Object

A cache implementation for region locations from meta.

Field Summary

Fields

Modifier and Type	Field	Description
private final ConcurrentMap<TableName,ConcurrentNavigableMap<byte[],RegionLocations>>	cachedRegionLocations	Map of table to table HRegionLocations.
private final Set<ServerName>	cachedServers
private static final org.slf4j.Logger	LOG
private final MetricsConnection	metrics

Constructor Summary

Constructors

Constructor	Description
MetaCache(MetricsConnection metrics)

Method Summary

Modifier and Type	Method	Description
private void	addToCachedServers(RegionLocations locations)
void	cacheLocation(TableName tableName, RegionLocations locations)	Put a newly discovered HRegionLocation into the cache.
void	cacheLocation(TableName tableName, ServerName source, HRegionLocation location)	Put a newly discovered HRegionLocation into the cache.
void	clearCache()	Delete all cached entries.
void	clearCache(RegionInfo hri)	Deletes the cached location of the region if necessary, based on some error from source. Synchronized because of calls in cacheLocation which need to be executed atomically
void	clearCache(ServerName serverName)	Delete all cached entries of a server.
void	clearCache(TableName tableName)	Delete all cached entries of a table. Synchronized because of calls in cacheLocation which need to be executed atomically
void	clearCache(TableName tableName, byte[] row)	Delete a cached location, no matter what it is.
void	clearCache(TableName tableName, byte[] row, int replicaId)	Delete a cached location with specific replicaId. Synchronized because of calls in cacheLocation which need to be executed atomically
void	clearCache(TableName tableName, byte[] row, ServerName serverName)	Delete a cached location for a table, row and server.
RegionLocations	getCachedLocation(TableName tableName, byte[] row)	Search the cache for a location that fits our table and row key.
int	getNumberOfCachedRegionLocations(TableName tableName)	Return the number of cached region for a table.
private ConcurrentNavigableMap<byte[],RegionLocations>	getTableLocations(TableName tableName)	Returns Map of cached locations for passed tableName. Despite being Concurrent, writes to the map should be synchronized because we have cases where we need to make multiple updates atomically.
boolean	isRegionCached(TableName tableName, byte[] row)	Check the region cache to see whether a region is cached yet or not.

Methods inherited from class java.lang.Object

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

Field Details

LOG

private static final org.slf4j.Logger LOG

cachedRegionLocations

private final ConcurrentMap<TableName,ConcurrentNavigableMap<byte[],RegionLocations>> cachedRegionLocations

Map of table to table HRegionLocations.
Despite being Concurrent, writes to the map should be synchronized because we have cases where we need to make multiple updates atomically.

cachedServers

private final Set<ServerName> cachedServers

metrics

private final MetricsConnection metrics

Constructor Details

MetaCache

public MetaCache(MetricsConnection metrics)

Method Details

getCachedLocation

public RegionLocations getCachedLocation(TableName tableName,
 byte[] row)

Search the cache for a location that fits our table and row key. Return null if no suitable region is located.

Returns:

Null or region location found in cache.

cacheLocation

public void cacheLocation(TableName tableName,
 ServerName source,
 HRegionLocation location)

Put a newly discovered HRegionLocation into the cache. Synchronize here because we may need to make multiple modifications in cleanProblematicOverlappedRegions, and we want them to be atomic.

Parameters:

tableName - The table name.

source - the source of the new location

location - the new location

cacheLocation

public void cacheLocation(TableName tableName,
 RegionLocations locations)

Put a newly discovered HRegionLocation into the cache. Synchronize here because we may need to make multiple modifications in cleanProblematicOverlappedRegions, and we want them to be atomic.

Parameters:

tableName - The table name.

locations - the new locations

addToCachedServers

private void addToCachedServers(RegionLocations locations)

getTableLocations

private ConcurrentNavigableMap<byte[],RegionLocations> getTableLocations(TableName tableName)

Returns Map of cached locations for passed tableName.
Despite being Concurrent, writes to the map should be synchronized because we have cases where we need to make multiple updates atomically.

isRegionCached

public boolean isRegionCached(TableName tableName,
 byte[] row)

Check the region cache to see whether a region is cached yet or not.

Parameters:

tableName - tableName

row - row

Returns:

Region cached or not.

getNumberOfCachedRegionLocations

public int getNumberOfCachedRegionLocations(TableName tableName)

Return the number of cached region for a table. It will only be called from a unit test.

clearCache

public void clearCache()

Delete all cached entries.
Synchronized because of calls in cacheLocation which need to be executed atomically

clearCache

public void clearCache(ServerName serverName)

Delete all cached entries of a server.
Synchronized because of calls in cacheLocation which need to be executed atomically

clearCache

public void clearCache(TableName tableName,
 byte[] row)

Delete a cached location, no matter what it is. Called when we were told to not use cache.
Synchronized because of calls in cacheLocation which need to be executed atomically

Parameters:

tableName - tableName

clearCache

public void clearCache(TableName tableName)

Delete all cached entries of a table.
Synchronized because of calls in cacheLocation which need to be executed atomically

clearCache

public void clearCache(TableName tableName,
 byte[] row,
 int replicaId)

Delete a cached location with specific replicaId.
Synchronized because of calls in cacheLocation which need to be executed atomically

Parameters:

tableName - tableName

row - row key

replicaId - region replica id

clearCache

public void clearCache(TableName tableName,
 byte[] row,
 ServerName serverName)

Delete a cached location for a table, row and server.
Synchronized because of calls in cacheLocation which need to be executed atomically

clearCache

public void clearCache(RegionInfo hri)

Deletes the cached location of the region if necessary, based on some error from source.
Synchronized because of calls in cacheLocation which need to be executed atomically

Parameters:

hri - The region in question.