Here is some code to fix .META. hole…after running it you can copy the data
from old
region in HDFS into newly created region. This is just hack code. Needs to be
turned into a utility with decent parameters that can be passed in to automate
it. Right now you manually paste your info into this code, and compile it…yuck.
But it’s the hack I’ve got, and it works for me.
======================
import java.util.logging.Level;
import java.util.logging.Logger;
import org.apache.hadoop.hbase.client.Get;
import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.client.Delete;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.util.Writables;
import org.apache.hadoop.hbase.client.HBaseAdmin;
public class FixMetaTable {
public static String regionNameKey = "YOUR REGION **NAME** here”;//replace
with YOUR regionName that needs fixin’
public static void main(String[] args) throws InterruptedException {
try {
System.out.println("Entering the Program to Edit .META. table");
Configuration hConfig = HBaseConfiguration.create();
hConfig.set("hbase.zookeeper.quorum", "your-quorum-here");
HBaseAdmin admin = new HBaseAdmin(hConfig);
HTable hTable = new HTable(hConfig, Bytes.toBytes(".META."));
Get get = new Get(Bytes.toBytes(regionNameKey));
Result result = hTable.get(get);
byte[] bytes = result.getValue(HConstants.CATALOG_FAMILY,
HConstants.REGIONINFO_QUALIFIER);
HRegionInfo closedRegion = Writables.getHRegionInfo(bytes);
admin.closeRegion(closedRegion.getRegionName(), null);//. Close the
existing region if open.
System.out.println("Closed the Region " +
closedRegion.getRegionNameAsString());
HTable readTable = new HTable(hConfig, Bytes.toBytes(".META."));
Get readGet = new Get(Bytes.toBytes(regionNameKey));
Result readResult = readTable.get(readGet);
byte[] readBytes = readResult.getValue(HConstants.CATALOG_FAMILY,
HConstants.REGIONINFO_QUALIFIER);
HRegionInfo existingRegion = Writables.getHRegionInfo(readBytes);
//Read the existing hregioninfo.
System.out.println("Read the existing region info after closing " +
existingRegion.getRegionNameAsString());
HTableDescriptor descriptor = new
HTableDescriptor(existingRegion.getTableDesc()); //Use existing hregioninfo
htabledescriptor and this construction
// Just changing the End key , nothing else
HRegionInfo newRegion = new HRegionInfo(descriptor,
Bytes.toBytes("startkey-of-row-whose-endkey-needs-fixing "),
Bytes.toBytes("FIXME")); //FIXME should be the corrected endkey…should be the
next startkey in .META.
byte[] value = Writables.getBytes(newRegion);
Put put = new Put(newRegion.getRegionName()); // Same time stamp
from the record.
put.add(HConstants.CATALOG_FAMILY, HConstants.REGIONINFO_QUALIFIER,
value);//Insert the new entry in .META. using new hregioninfo name as row key
and add an info:regioninfo whose contents is the serialized new hregioninfo.
HTable metaTable = new HTable(hConfig, ".META.");
metaTable.put(put);
System.out.println("Put a new Region " +
newRegion.getRegionNameAsString() + " End key is " +
Bytes.toString(newRegion.getEndKey()));
Delete del = new Delete(closedRegion.getRegionName());//Delete the
original row from .META.
metaTable.delete(del);
System.out.println("Deleted the closed region " +
closedRegion.getRegionNameAsString());
admin.assign(newRegion.getRegionName(), true); //Assign the new
region.
System.out.println("Assigned the new region " +
newRegion.getRegionNameAsString());
} catch (IOException ex) {
Logger.getLogger(FixMetaTable.class.getName()).log(Level.SEVERE,
null, ex);
}
}
}
From: Geoff Hendrey
Sent: Wednesday, September 07, 2011 12:11 PM
To: [email protected]
Cc: [email protected]; [email protected]
Subject: Re: What's .META.'s hole?
Not in front of my laptop now, but I'll email our hole fixing code to the list
this PM.
Sent from my iPhone
On Sep 7, 2011, at 11:57 AM, "Jonathan Hsieh" <[email protected]> wrote:
Hey Geoff,
I've been working on some code that should help show (HBASE-4321, HBASE-
43222) where holes are (and overlaps and other kinds of meta problems).
Can you point me to the jiras/code with fixup routines?
Thanks,
Jon.
On Sun, Sep 4, 2011 at 8:15 PM, Geoff Hendrey <[email protected]>
wrote:
> a "hole" means when you run "hbase hbck" you see "chain of regions in
> table <TABLENAME> is broken; edges does not contain <STARTROW>"
>
> What happens is the endrow of a entry in .META. points to a
nonexistent
> start row. Based on StAck's steps for fixing the problem, we wrote
tool
> to repair it. Essentially the tool fixes the end row so that it points
> to the next startrow in .META.
>
> I believe Rohit posted the code that will fix the hole...
>
> -geoff
>
> -----Original Message-----
> From: Mingjian Deng [mailto:[email protected]]
> Sent: Sunday, September 04, 2011 6:10 PM
> To: [email protected]
> Subject: What's .META.'s hole?
>
> Hi All:
> I don't know what does hole in .META. mean.
> There is a regions in my cluster have "serverinfo" and "startcode"
> in
> .META. without "regioninfo". Is it hole? How did it happned and how to
> fix
> it?
>
--
// Jonathan Hsieh (shay)
// Software Engineer, Cloudera
// [email protected]
