org.apache.hadoop.hbase.coprocessor

Interface WALObserver

All Superinterfaces:

Coprocessor

All Known Implementing Classes:

BaseWALObserver

@InterfaceAudience.LimitedPrivate(value="Coprocesssor")
@InterfaceStability.Evolving
public interface WALObserver
extends Coprocessor

It's provided to have a way for coprocessors to observe, rewrite, or skip WALEdits as they are being written to the WAL. RegionObserver provides hooks for adding logic for WALEdits in the region context during reconstruction, Defines coprocessor hooks for interacting with operations on the HLog.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.hadoop.hbase.Coprocessor

Coprocessor.State

Field Summary

Fields inherited from interface org.apache.hadoop.hbase.Coprocessor

PRIORITY_HIGHEST, PRIORITY_LOWEST, PRIORITY_SYSTEM, PRIORITY_USER, VERSION

Method Summary

Methods

Modifier and Type	Method and Description
void	postWALWrite(ObserverContext<WALCoprocessorEnvironment> ctx, HRegionInfo info, HLogKey logKey, WALEdit logEdit) Called after a WALEdit is writen to WAL.
boolean	preWALWrite(ObserverContext<WALCoprocessorEnvironment> ctx, HRegionInfo info, HLogKey logKey, WALEdit logEdit) Called before a WALEdit is writen to WAL.

Methods inherited from interface org.apache.hadoop.hbase.Coprocessor

start, stop

Method Detail

preWALWrite

boolean preWALWrite(ObserverContext<WALCoprocessorEnvironment> ctx,
                  HRegionInfo info,
                  HLogKey logKey,
                  WALEdit logEdit)
                    throws IOException

Called before a WALEdit is writen to WAL.

Parameters:

ctx -

info -

logKey -

logEdit -

Returns:

true if default behavior should be bypassed, false otherwise

Throws:

IOException

postWALWrite

void postWALWrite(ObserverContext<WALCoprocessorEnvironment> ctx,
                HRegionInfo info,
                HLogKey logKey,
                WALEdit logEdit)
                  throws IOException

Called after a WALEdit is writen to WAL.

Parameters:

ctx -

info -

logKey -

logEdit -

Throws:

IOException