RegionPlacementMaintainer (Apache HBase 1.2.12 API)

java.lang.Object
- org.apache.hadoop.hbase.master.RegionPlacementMaintainer

```
@InterfaceAudience.Private
public class RegionPlacementMaintainer
extends Object
```
A tool that is used for manipulating and viewing favored nodes information for regions. Run with -h to get a list of the options

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`protected static class`	`RegionPlacementMaintainer.RandomizedMatrix` Some algorithms for solving the assignment problem may traverse workers or jobs in linear order which may result in skewing the assignments of the first jobs in the matrix toward the last workers in the matrix if the costs are uniform.

Field Summary

Fields
Modifier and Type	Field and Description
`private static float`	`AVOID_COST`
`private org.apache.hadoop.conf.Configuration`	`conf`
`private Connection`	`connection`
`private boolean`	`enforceLocality`
`private boolean`	`enforceMinAssignmentMove`
`private static float`	`LAST_SLOT_COST_PENALTY`
`private static org.apache.commons.logging.Log`	`LOG`
`private static float`	`MAX_COST`
`private static float`	`NOT_CURRENT_HOST_PENALTY`
`private RackManager`	`rackManager`
`private Set<TableName>`	`targetTableSet`
`private static boolean`	`USE_MUNKRES_FOR_PLACING_SECONDARY_AND_TERTIARY`

Constructor Summary

Constructors
Constructor and Description
`RegionPlacementMaintainer(org.apache.hadoop.conf.Configuration conf)`
`RegionPlacementMaintainer(org.apache.hadoop.conf.Configuration conf, boolean enforceLocality, boolean enforceMinAssignmentMove)`

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`checkDifferencesWithOldPlan(Map<TableName,Integer> movesPerTable, Map<String,Map<String,Float>> regionLocalityMap, FavoredNodesPlan newPlan)` Compares two plans and check whether the locality dropped or increased (prints the information as a string) also prints the baseline locality
`private void`	`genAssignmentPlan(TableName tableName, SnapshotOfRegionAssignmentFromMeta assignmentSnapshot, Map<String,Map<String,Float>> regionLocalityMap, FavoredNodesPlan plan, boolean munkresForSecondaryAndTertiary)` Generate the assignment plan for the existing table
`static List<ServerName>`	`getFavoredNodeList(String favoredNodesStr)`
`FavoredNodesPlan`	`getNewAssignmentPlan()`
`SnapshotOfRegionAssignmentFromMeta`	`getRegionAssignmentSnapshot()`
`Map<TableName,Integer>`	`getRegionsMovement(FavoredNodesPlan newPlan)` Return how many regions will move per table since their primary RS will change
`static void`	`main(String[] args)`
`static void`	`printAssignmentPlan(FavoredNodesPlan plan)` Print the assignment plan to the system output stream
`void`	`printDispersionScores(TableName table, SnapshotOfRegionAssignmentFromMeta snapshot, int numRegions, FavoredNodesPlan newPlan, boolean simplePrint)`
`private static void`	`printHelp(org.apache.commons.cli.Options opt)`
`void`	`printLocalityAndDispersionForCurrentPlan(Map<String,Map<String,Float>> regionLocalityMap)`
`void`	`setTargetTableName(String[] tableNames)`
`void`	`updateAssignmentPlan(FavoredNodesPlan plan)`
`void`	`updateAssignmentPlanToMeta(FavoredNodesPlan plan)` Update the assignment plan into hbase:meta
`private void`	`updateAssignmentPlanToRegionServers(FavoredNodesPlan plan)` Update the assignment plan to all the region servers
`List<AssignmentVerificationReport>`	`verifyRegionPlacement(boolean isDetailMode)` Verify the region placement is consistent with the assignment plan

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LOG

private static final org.apache.commons.logging.Log LOG

MAX_COST
```
private static final float MAX_COST
```
See Also:
Constant Field Values

AVOID_COST
```
private static final float AVOID_COST
```
See Also:
Constant Field Values

LAST_SLOT_COST_PENALTY
```
private static final float LAST_SLOT_COST_PENALTY
```
See Also:
Constant Field Values

NOT_CURRENT_HOST_PENALTY
```
private static final float NOT_CURRENT_HOST_PENALTY
```
See Also:
Constant Field Values

USE_MUNKRES_FOR_PLACING_SECONDARY_AND_TERTIARY

private static boolean USE_MUNKRES_FOR_PLACING_SECONDARY_AND_TERTIARY

conf

private org.apache.hadoop.conf.Configuration conf

enforceLocality
```
private final boolean enforceLocality
```

enforceMinAssignmentMove

private final boolean enforceMinAssignmentMove

rackManager
```
private RackManager rackManager
```

targetTableSet
```
private Set<TableName> targetTableSet
```

connection
```
private final Connection connection
```

Constructor Detail

RegionPlacementMaintainer

public RegionPlacementMaintainer(org.apache.hadoop.conf.Configuration conf)

RegionPlacementMaintainer

public RegionPlacementMaintainer(org.apache.hadoop.conf.Configuration conf,
                         boolean enforceLocality,
                         boolean enforceMinAssignmentMove)

Method Detail

printHelp

private static void printHelp(org.apache.commons.cli.Options opt)

setTargetTableName

public void setTargetTableName(String[] tableNames)

getRegionAssignmentSnapshot

public SnapshotOfRegionAssignmentFromMeta getRegionAssignmentSnapshot()
                                                               throws IOException

Returns:: the new RegionAssignmentSnapshot
Throws:: IOException

verifyRegionPlacement

public List<AssignmentVerificationReport> verifyRegionPlacement(boolean isDetailMode)
                                                         throws IOException

Verify the region placement is consistent with the assignment plan

Parameters:: isDetailMode -
Returns:: reports
Throws:: IOException

genAssignmentPlan

private void genAssignmentPlan(TableName tableName,
                     SnapshotOfRegionAssignmentFromMeta assignmentSnapshot,
                     Map<String,Map<String,Float>> regionLocalityMap,
                     FavoredNodesPlan plan,
                     boolean munkresForSecondaryAndTertiary)
                        throws IOException

Generate the assignment plan for the existing table

Parameters:: tableName -; assignmentSnapshot -; regionLocalityMap -; plan -; munkresForSecondaryAndTertiary - if set on true the assignment plan for the tertiary and secondary will be generated with Munkres algorithm, otherwise will be generated using placeSecondaryAndTertiaryRS
Throws:: IOException

getNewAssignmentPlan

public FavoredNodesPlan getNewAssignmentPlan()
                                      throws IOException

Throws:: IOException

printAssignmentPlan
```
public static void printAssignmentPlan(FavoredNodesPlan plan)
```
Print the assignment plan to the system output stream

Parameters:
plan -

updateAssignmentPlanToMeta
```
public void updateAssignmentPlanToMeta(FavoredNodesPlan plan)
                                throws IOException
```
Update the assignment plan into hbase:meta

Parameters:
plan - the assignments plan to be updated into hbase:meta

Throws:

IOException - if cannot update assignment plan in hbase:meta

updateAssignmentPlanToRegionServers

private void updateAssignmentPlanToRegionServers(FavoredNodesPlan plan)
                                          throws IOException

Update the assignment plan to all the region servers

Parameters:: plan -
Throws:: IOException

updateAssignmentPlan

public void updateAssignmentPlan(FavoredNodesPlan plan)
                          throws IOException

Throws:: IOException

getRegionsMovement
```
public Map<TableName,Integer> getRegionsMovement(FavoredNodesPlan newPlan)
                                          throws IOException
```
Return how many regions will move per table since their primary RS will change

Parameters:
newPlan - - new AssignmentPlan

Returns:
how many primaries will move per table

Throws:

IOException

checkDifferencesWithOldPlan

public void checkDifferencesWithOldPlan(Map<TableName,Integer> movesPerTable,
                               Map<String,Map<String,Float>> regionLocalityMap,
                               FavoredNodesPlan newPlan)
                                 throws IOException

Compares two plans and check whether the locality dropped or increased (prints the information as a string) also prints the baseline locality

Parameters:: movesPerTable - - how many primary regions will move per table; regionLocalityMap - - locality map from FS; newPlan - - new assignment plan
Throws:: IOException

printDispersionScores

public void printDispersionScores(TableName table,
                         SnapshotOfRegionAssignmentFromMeta snapshot,
                         int numRegions,
                         FavoredNodesPlan newPlan,
                         boolean simplePrint)

printLocalityAndDispersionForCurrentPlan

public void printLocalityAndDispersionForCurrentPlan(Map<String,Map<String,Float>> regionLocalityMap)
                                              throws IOException

Throws:: IOException

getFavoredNodeList
```
public static List<ServerName> getFavoredNodeList(String favoredNodesStr)
```
Parameters:
favoredNodesStr - The String of favored nodes

Returns:
the list of ServerName for the byte array of favored nodes.

main

public static void main(String[] args)
                 throws IOException

Throws:: IOException

Class RegionPlacementMaintainer

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

LOG

MAX_COST

AVOID_COST

LAST_SLOT_COST_PENALTY

NOT_CURRENT_HOST_PENALTY

USE_MUNKRES_FOR_PLACING_SECONDARY_AND_TERTIARY

conf

enforceLocality

enforceMinAssignmentMove

rackManager

targetTableSet

connection

Constructor Detail

RegionPlacementMaintainer

RegionPlacementMaintainer

Method Detail

printHelp

setTargetTableName

getRegionAssignmentSnapshot

verifyRegionPlacement

genAssignmentPlan

getNewAssignmentPlan

printAssignmentPlan

updateAssignmentPlanToMeta

updateAssignmentPlanToRegionServers

updateAssignmentPlan

getRegionsMovement

checkDifferencesWithOldPlan

printDispersionScores

printLocalityAndDispersionForCurrentPlan

getFavoredNodeList

main