Package org.apache.accumulo.core.spi.balancer

Class RegexGroupBalancer

java.lang.Object

org.apache.accumulo.core.spi.balancer.GroupBalancer

org.apache.accumulo.core.spi.balancer.RegexGroupBalancer

All Implemented Interfaces:

TabletBalancer

public class RegexGroupBalancer
extends GroupBalancer

A GroupBalancer that groups tablets using a configurable regex. To use this balancer configure the following settings for your table then configure this balancer for your table.

• Set table.custom.balancer.group.regex.pattern to a regular expression. This regular expression must have one group. The regex is applied to the tablet end row and whatever the regex group matches is used as the group. For example with a regex of (\d\d).* and an end row of 12abc, the group for the tablet would be 12.
• Set table.custom.balancer.group.regex.default to a default group. This group is returned for the last tablet in the table and tablets for which the regex does not match.
• Optionally set table.custom.balancer.group.regex.wait.time to time (can use time suffixes). This determines how long to wait between balancing. Since this balancer scans the metadata table, may want to set this higher for large tables.

Since:

2.1.0

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.accumulo.core.spi.balancer.TabletBalancer

TabletBalancer.AssignmentParameters, TabletBalancer.BalanceParameters

Field Summary

Fields

Modifier and Type	Field	Description
static final String	DEFAUT_GROUP_PROPERTY
static final String	REGEX_PROPERTY
static final String	WAIT_TIME_PROPERTY

Fields inherited from class org.apache.accumulo.core.spi.balancer.GroupBalancer

environment

Constructor Summary

Constructors

Constructor	Description
RegexGroupBalancer(TableId tableId)

Method Summary

Modifier and Type	Method	Description
protected Function<TabletId,String>	getPartitioner()
protected long	getWaitTime()	The amount of time to wait between balancing.

Methods inherited from class org.apache.accumulo.core.spi.balancer.GroupBalancer

balance, getAssignments, getLocationProvider, getMaxMigrations, init, shouldBalance

Methods inherited from class java.lang.Object

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

Field Details

REGEX_PROPERTY

public static final String REGEX_PROPERTY

DEFAUT_GROUP_PROPERTY

public static final String DEFAUT_GROUP_PROPERTY

WAIT_TIME_PROPERTY

public static final String WAIT_TIME_PROPERTY

Constructor Details

RegexGroupBalancer

public RegexGroupBalancer(TableId tableId)

Method Details

getWaitTime

protected long getWaitTime()

Description copied from class: GroupBalancer

The amount of time to wait between balancing.

Overrides:

getWaitTime in class GroupBalancer

getPartitioner

protected Function<TabletId,String> getPartitioner()

Specified by:

getPartitioner in class GroupBalancer

Returns:

A function that groups tablets into named groups.