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From: Serega Sheypak <serega.sheypak@gmail.com>
Date: Fri, 3 Oct 2014 21:57:56 +0400
Message-ID: 
 <CABNOTEVZigjfwq85k486JHvAv-iJV7bTmYCdpCi7p2XoWT-HQw@mail.gmail.com>
Subject: Re: Splits are not preserved during table copy using
 getAdmin().createTable(tableDescriptor);
To: user <user@hbase.apache.org>
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Do I have to pass an array of startKeys or an array of endKeys?

2014-10-03 20:29 GMT+04:00 Serega Sheypak <serega.sheypak@gmail.com>:

> So easy, thanks :) I've missed that method.
>
> 2014-10-03 20:23 GMT+04:00 Ted Yu <yuzhihong@gmail.com>:
>
>> You can simplify your code by utilizing the following from HTable:
>>
>>   public byte [][] getStartKeys() throws IOException {
>>
>> No need to sort the keys.
>>
>> Cheers
>>
>> On Fri, Oct 3, 2014 at 9:10 AM, Serega Sheypak <serega.sheypak@gmail.com>
>> wrote:
>>
>> > Thanks, I'm already updated my end-to-end test, waiting for the result.
>> >
>> > Here is my code snippet, is it ok?
>> >
>> >  @SneakyThrows(IOException.class)
>> >     private byte[][] collectSplits(String tableName){
>> >         HTable table = new HTable(configuration, tableName);
>> >         int splitSize =
>> > table.getRegionLocations().descendingKeySet().size();
>> >
>> >         if(splitSize < 2){
>> >             LOG.info(String.format("There is only one region for a
>> > table[%s]. No splits to recreate", tableName));
>> >             return new byte[][]{};
>> >         }
>> >         LOG.info(String.format("There are [%s] regions for a table[%s].
>> > Skip pre-splitting", splitSize, tableName));
>> >
>> >         byte[][] splits = new byte[splitSize][];
>> >       *  Iterator<HRegionInfo> itr =
>> > table.getRegionLocations().descendingKeySet().iterator();*
>> > *        int index = 0;*
>> > *        while (itr.hasNext()){*
>> > *            splits[index] = itr.next().getStartKey();*
>> > *            index++;*
>> > *        }*
>> >
>> >         table.close();
>> >
>> >         Arrays.sort(splits, Bytes.BYTES_COMPARATOR);
>> >         return splits;
>> >     }
>> >
>> >
>> > 2014-10-03 20:02 GMT+04:00 Ted Yu <yuzhihong@gmail.com>:
>> >
>> > > Take a look at this method in HTable:
>> > >
>> > >   public Pair<byte[][],byte[][]> getStartEndKeys() throws IOException
>> {
>> > >
>> > > You would see that the first dimension corresponds to the number of
>> > > regions.
>> > >
>> > >
>> > > Cheers
>> > >
>> > > On Fri, Oct 3, 2014 at 8:33 AM, Serega Sheypak <
>> serega.sheypak@gmail.com
>> > >
>> > > wrote:
>> > >
>> > > > Ok, I found them:
>> > > > hTable.getRegionLocations().descendingKeySet()
>> > > > and
>> > > > HRegionInfo has startKey and endKey
>> > > > I have to prepare splits[][].
>> > > > I'm confused a little, how keys should be placed there? splits[][]
>> > shoud
>> > > by
>> > > > and array with length=region count and width = 2?
>> > > >
>> > > >
>> > > > 2014-10-03 17:57 GMT+04:00 Serega Sheypak <serega.sheypak@gmail.com
>> >:
>> > > >
>> > > > > Hi, here is my code:
>> > > > >
>> > > > > public void dropIfExistsAndCreate(String sourceTableName, String
>> > > > > newTableName) throws IOException {
>> > > > >         LOG.info(String.format("Use [%s] to create [%s]",
>> > > > sourceTableName,
>> > > > > newTableName));
>> > > > >         HTableDescriptor descriptor =
>> getDescriptor(sourceTableName);
>> > > > >         dropIfExists(newTableName); // doesn't matter
>> > > > >         createTable(descriptor, newTableName);
>> > > > >     }
>> > > > >
>> > > > >     private void createTable(HTableDescriptor descriptor, String
>> > > > > newTableName) throws IOException {
>> > > > >         descriptor.setName(Bytes.toBytes(newTableName));
>> > > > >         getAdmin().createTable(descriptor);
>> > > > >         LOG.info(String.format("Table created[%s]",
>> newTableName));
>> > > > >     }
>> > > > >
>> > > > > My source table has 256 regions, newly created table has no
>> splits.
>> > > > > Is there any possibility to copy splits from source table?
>> > > > >
>> > > > > I supposed, that HTableDescriptor encasulates splits, but it was
>> bad
>> > > > > assumption.
>> > > > >
>> > > >
>> > >
>> >
>>
>
>

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