@InterfaceAudience.Public
@InterfaceStability.Evolving
public class TableSnapshotScanner
extends org.apache.hadoop.hbase.client.AbstractClientScanner
This also allows one to run the scan from an
online or offline hbase cluster. The snapshot files can be exported by using the
ExportSnapshot tool, to a pure-hdfs cluster,
and this scanner can be used to run the scan directly over the snapshot files.
The snapshot should not be deleted while there are open scanners reading from snapshot
files.
An internal RegionScanner is used to execute the Scan obtained
from the user for each region in the snapshot.
HBase owns all the data and snapshot files on the filesystem. Only the HBase user can read from snapshot files and data files. HBase also enforces security because all the requests are handled by the server layer, and the user cannot read from the data files directly. To read from snapshot files directly from the file system, the user who is running the MR job must have sufficient permissions to access snapshot and reference files. This means that to run mapreduce over snapshot files, the job has to be run as the HBase user or the user must have group or other priviledges in the filesystem (See HBASE-8369). Note that, given other users access to read from snapshot/data files will completely circumvent the access control enforced by HBase.
TableSnapshotInputFormat| Constructor and Description |
|---|
TableSnapshotScanner(org.apache.hadoop.conf.Configuration conf,
org.apache.hadoop.fs.Path rootDir,
org.apache.hadoop.fs.Path restoreDir,
String snapshotName,
Scan scan)
Creates a TableSnapshotScanner.
|
TableSnapshotScanner(org.apache.hadoop.conf.Configuration conf,
org.apache.hadoop.fs.Path restoreDir,
String snapshotName,
Scan scan)
Creates a TableSnapshotScanner.
|
| Modifier and Type | Method and Description |
|---|---|
void |
close()
Closes the scanner and releases any resources it has allocated
|
Result |
next()
Grab the next row's worth of values.
|
boolean |
renewLease()
Allow the client to renew the scanner's lease on the server.
|
public TableSnapshotScanner(org.apache.hadoop.conf.Configuration conf,
org.apache.hadoop.fs.Path restoreDir,
String snapshotName,
Scan scan)
throws IOException
conf - the configurationrestoreDir - a temporary directory to copy the snapshot files into. Current user should
have write permissions to this directory, and this should not be a subdirectory of rootdir.
The scanner deletes the contents of the directory once the scanner is closed.snapshotName - the name of the snapshot to read fromscan - a Scan representing scan parametersIOException - in case of errorpublic TableSnapshotScanner(org.apache.hadoop.conf.Configuration conf,
org.apache.hadoop.fs.Path rootDir,
org.apache.hadoop.fs.Path restoreDir,
String snapshotName,
Scan scan)
throws IOException
conf - the configurationrootDir - root directory for HBase.restoreDir - a temporary directory to copy the snapshot files into. Current user should
have write permissions to this directory, and this should not be a subdirectory of rootdir.
The scanner deletes the contents of the directory once the scanner is closed.snapshotName - the name of the snapshot to read fromscan - a Scan representing scan parametersIOException - in case of errorpublic Result next() throws IOException
ResultScannerIOException - epublic void close()
ResultScannerpublic boolean renewLease()
org.apache.hadoop.hbase.client.AbstractClientScannerrenewLease in class org.apache.hadoop.hbase.client.AbstractClientScannerCopyright © 2007–2016 The Apache Software Foundation. All rights reserved.