org.apache.hadoop.hbase.catalog
Class MetaReader

java.lang.Object
  org.apache.hadoop.hbase.catalog.MetaReader

public class MetaReader
extends Object

Reads region and assignment information from .META..

Uses the CatalogTracker to obtain locations and connections to catalogs.

Nested Class Summary

static interface

MetaReader.Visitor Implementations 'visit' a catalog table row.

Field Summary

static byte[]

META_REGION_PREFIX

Constructor Summary

MetaReader()

Method Summary

static Map<HRegionInfo,HServerAddress>	fullScan(CatalogTracker catalogTracker) Performs a full scan of .META..
static void	fullScan(CatalogTracker catalogTracker, MetaReader.Visitor visitor) Performs a full scan of .META..
static void	fullScan(CatalogTracker catalogTracker, MetaReader.Visitor visitor, byte[] startrow) Performs a full scan of .META..
static Map<HRegionInfo,HServerAddress>	fullScan(CatalogTracker catalogTracker, Set<String> disabledTables) Performs a full scan of .META., skipping regions from any tables in the specified set of disabled tables.
static Map<HRegionInfo,HServerAddress>	fullScan(CatalogTracker catalogTracker, Set<String> disabledTables, boolean excludeOfflinedSplitParents) Performs a full scan of .META., skipping regions from any tables in the specified set of disabled tables.
static List<Result>	fullScanOfResults(CatalogTracker catalogTracker) Performs a full scan of .META..
static Pair<HRegionInfo,HServerAddress>	getRegion(CatalogTracker catalogTracker, byte[] regionName) Gets the region info and assignment for the specified region from META.
static Scan	getScanForTableName(byte[] tableName) This method creates a Scan object that will only scan catalog rows that belong to the specified table.
static NavigableMap<HRegionInfo,Result>	getServerUserRegions(CatalogTracker catalogTracker, HServerInfo hsi)
static List<HRegionInfo>	getTableRegions(CatalogTracker catalogTracker, byte[] tableName) Gets all of the regions of the specified table.
static List<HRegionInfo>	getTableRegions(CatalogTracker catalogTracker, byte[] tableName, boolean excludeOfflinedSplitParents) Gets all of the regions of the specified table.
static List<Pair<HRegionInfo,HServerAddress>>	getTableRegionsAndLocations(CatalogTracker catalogTracker, String tableName)
static Pair<HRegionInfo,HServerAddress>	metaRowToRegionPair(Result data)
static Pair<HRegionInfo,HServerInfo>	metaRowToRegionPairWithInfo(Result data)
static HServerAddress	readMetaLocation(HRegionInterface metaServer) Reads the location of META from ROOT.
static HServerAddress	readRegionLocation(CatalogTracker catalogTracker, byte[] regionName) Reads the location of the specified region from META.
static boolean	tableExists(CatalogTracker catalogTracker, String tableName) Checks if the specified table exists.

Methods inherited from class java.lang.Object

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

Field Detail

META_REGION_PREFIX

public static final byte[] META_REGION_PREFIX

Constructor Detail

MetaReader

public MetaReader()

Method Detail

fullScan

public static Map<HRegionInfo,HServerAddress> fullScan(CatalogTracker catalogTracker)
                                                throws IOException

Performs a full scan of .META..

Returns a map of every region to it's currently assigned server, according to META. If the region does not have an assignment it will have a null value in the map.

Returns:

map of regions to their currently assigned server

Throws:

IOException

fullScan

public static Map<HRegionInfo,HServerAddress> fullScan(CatalogTracker catalogTracker,
                                                       Set<String> disabledTables)
                                                throws IOException

Performs a full scan of .META., skipping regions from any tables in the specified set of disabled tables.

Returns a map of every region to it's currently assigned server, according to META. If the region does not have an assignment it will have a null value in the map.

Parameters:

catalogTracker -

disabledTables - set of disabled tables that will not be returned

Returns:

map of regions to their currently assigned server

Throws:

IOException

fullScan

public static Map<HRegionInfo,HServerAddress> fullScan(CatalogTracker catalogTracker,
                                                       Set<String> disabledTables,
                                                       boolean excludeOfflinedSplitParents)
                                                throws IOException

Performs a full scan of .META., skipping regions from any tables in the specified set of disabled tables.

Returns a map of every region to it's currently assigned server, according to META. If the region does not have an assignment it will have a null value in the map.

Parameters:

catalogTracker -

disabledTables - set of disabled tables that will not be returned

excludeOfflinedSplitParents - If true, do not include offlined split parents in the return.

Returns:

map of regions to their currently assigned server

Throws:

IOException

fullScanOfResults

public static List<Result> fullScanOfResults(CatalogTracker catalogTracker)
                                      throws IOException

Performs a full scan of .META..

Returns a map of every region to it's currently assigned server, according to META. If the region does not have an assignment it will have a null value in the map.

Returns HServerInfo which includes server startcode.

Returns:

map of regions to their currently assigned server

Throws:

IOException

fullScan

public static void fullScan(CatalogTracker catalogTracker,
                            MetaReader.Visitor visitor)
                     throws IOException

Performs a full scan of .META..

Returns a map of every region to it's currently assigned server, according to META. If the region does not have an assignment it will have a null value in the map.

Parameters:

catalogTracker -

visitor -

Throws:

IOException

fullScan

public static void fullScan(CatalogTracker catalogTracker,
                            MetaReader.Visitor visitor,
                            byte[] startrow)
                     throws IOException

Performs a full scan of .META..

Returns a map of every region to it's currently assigned server, according to META. If the region does not have an assignment it will have a null value in the map.

Parameters:

catalogTracker -

visitor -

startrow - Where to start the scan. Pass null if want to begin scan at first row.

Throws:

IOException

readMetaLocation

public static HServerAddress readMetaLocation(HRegionInterface metaServer)
                                       throws IOException

Reads the location of META from ROOT.

Parameters:

metaServer - connection to server hosting ROOT

Returns:

location of META in ROOT, null if not available

Throws:

IOException

readRegionLocation

public static HServerAddress readRegionLocation(CatalogTracker catalogTracker,
                                                byte[] regionName)
                                         throws IOException

Reads the location of the specified region from META.

Parameters:

catalogTracker -

regionName - region to read location of

Returns:

location of region in META, null if not available

Throws:

IOException

getRegion

public static Pair<HRegionInfo,HServerAddress> getRegion(CatalogTracker catalogTracker,
                                                         byte[] regionName)
                                                  throws IOException

Gets the region info and assignment for the specified region from META.

Parameters:

catalogTracker -

regionName -

Returns:

region info and assignment from META, null if not available

Throws:

IOException

metaRowToRegionPair

public static Pair<HRegionInfo,HServerAddress> metaRowToRegionPair(Result data)
                                                            throws IOException

Parameters:

data - A .META. table row.

Returns:

A pair of the regioninfo and the server address from data or null for server address if no address set in .META. or null for a result if no HRegionInfo found.

Throws:

IOException

metaRowToRegionPairWithInfo

public static Pair<HRegionInfo,HServerInfo> metaRowToRegionPairWithInfo(Result data)
                                                                 throws IOException

Parameters:

data - A .META. table row.

Returns:

A pair of the regioninfo and the server info from data (or null for server address if no address set in .META.).

Throws:

IOException

tableExists

public static boolean tableExists(CatalogTracker catalogTracker,
                                  String tableName)
                           throws IOException

Checks if the specified table exists. Looks at the META table hosted on the specified server.

Parameters:

catalogTracker -

tableName - table to check

Returns:

true if the table exists in meta, false if not

Throws:

IOException

getTableRegions

public static List<HRegionInfo> getTableRegions(CatalogTracker catalogTracker,
                                                byte[] tableName)
                                         throws IOException

Gets all of the regions of the specified table.

Parameters:

catalogTracker -

tableName -

Returns:

Ordered list of HRegionInfo.

Throws:

IOException

getTableRegions

public static List<HRegionInfo> getTableRegions(CatalogTracker catalogTracker,
                                                byte[] tableName,
                                                boolean excludeOfflinedSplitParents)
                                         throws IOException

Gets all of the regions of the specified table.

Parameters:

catalogTracker -

tableName -

excludeOfflinedSplitParents - If true, do not include offlined split parents in the return.

Returns:

Ordered list of HRegionInfo.

Throws:

IOException

getScanForTableName

public static Scan getScanForTableName(byte[] tableName)

This method creates a Scan object that will only scan catalog rows that belong to the specified table. It doesn't specify any columns. This is a better alternative to just using a start row and scan until it hits a new table since that requires parsing the HRI to get the table name.

Parameters:

tableName - bytes of table's name

Returns:

configured Scan object

getTableRegionsAndLocations

public static List<Pair<HRegionInfo,HServerAddress>> getTableRegionsAndLocations(CatalogTracker catalogTracker,
                                                                                 String tableName)
                                                                          throws IOException,
                                                                                 InterruptedException

Parameters:

catalogTracker -

tableName -

Returns:

Return list of regioninfos and server addresses.

Throws:

IOException

InterruptedException

getServerUserRegions

public static NavigableMap<HRegionInfo,Result> getServerUserRegions(CatalogTracker catalogTracker,
                                                                    HServerInfo hsi)
                                                             throws IOException

Parameters:

catalogTracker -

hsi - Server specification

Returns:

List of user regions installed on this server (does not include catalog regions).

Throws:

IOException