Why writes a meta HRegionInfo for blockcache/InMemory is off to hdfs system?

[Gaojinchao <ga...@huawei.com>]

Below code is doing this when we start a cluster.

Code:
private static void bootstrap(final Path rd, final Configuration c)
  throws IOException {
    LOG.info("BOOTSTRAP: creating ROOT and first META regions");
    try {
      // Bootstrapping, make sure blockcache is off.  Else, one will be
      // created here in bootstap and it'll need to be cleaned up.  Better to
      // not make it in first place.  Turn off block caching for bootstrap.
      // Enable after.
      HRegionInfo rootHRI = new HRegionInfo(HRegionInfo.ROOT_REGIONINFO);
      setInfoFamilyCaching(rootHRI, false);
      HRegionInfo metaHRI = new HRegionInfo(HRegionInfo.FIRST_META_REGIONINFO);
      setInfoFamilyCaching(metaHRI, false);
      HRegion root = HRegion.createHRegion(rootHRI, rd, c);
      HRegion meta = HRegion.createHRegion(metaHRI, rd, c);
      setInfoFamilyCaching(rootHRI, true);
      setInfoFamilyCaching(metaHRI, true);

I found “IN_MEMORY => 'false', BLOCKCACHE => 'false'”  in hdfs system.

       .META.,,1.META.[1]IS_ROOTfalseIS_META
________________________________
true
________________________________
info
BLOOMFILTER
________________________________
NONEREPLICATION_SCOPE0
COMPRESSION
________________________________
NONEVERSIONS[1]10
________________________________
TTL
2147483647     BLOCKSIZE
________________________________
8192     IN_MEMORYfalse
BLOCKCACHEfalseK��

REGION => {NAME => '.META.,,1', STARTKEY => '', ENDKEY => '', ENCODED => 1028785192, TABLE => {{NAME => '.META.', IS_META => 'true', FAMILIES => [{NAME => 'info', BLOOMFILTER => 'NONE', REPLICATION_SCOPE => '0', COMPRESSION => 'NONE', VERSIONS => '10', TTL => '2147483647', BLOCKSIZE => '8192', IN_MEMORY => 'false', BLOCKCACHE => 'false'}]}}

Re: Why writes a meta HRegionInfo for blockcache/InMemory is off to hdfs system?

[Gaojinchao <ga...@huawei.com>]

Thanks for your reply.

I checked the heath of the cluster and found this issue. I went through the code and 
have not found any place using this information. I suspect this code is not useful.
I wanted to know why do this , checking the SVN couldn't find any useful information(
Maybe this code was merged a long time ago). 


-----邮件原件-----
发件人: saint.ack@gmail.com [mailto:saint.ack@gmail.com] 代表 Stack
发送时间: 2012年1月6日 13:07
收件人: dev@hbase.apache.org
主题: Re: Why writes a meta HRegionInfo for blockcache/InMemory is off to hdfs system?

On Thu, Jan 5, 2012 at 3:01 AM, Gaojinchao <ga...@huawei.com> wrote:
> I found “IN_MEMORY => 'false', BLOCKCACHE => 'false'”  in hdfs system.
>
>       .META.,,1 .META.[1]IS_ROOTfalseIS_META

What you thinking Jinchao?  We should set IN_MEMORY true?  What else?
St.Ack

Re: Why writes a meta HRegionInfo for blockcache/InMemory is off to hdfs system?

[Stack <st...@duboce.net>]

On Thu, Jan 5, 2012 at 3:01 AM, Gaojinchao <ga...@huawei.com> wrote:
> I found “IN_MEMORY => 'false', BLOCKCACHE => 'false'”  in hdfs system.
>
>       .META.,,1 .META.[1]IS_ROOTfalseIS_META

What you thinking Jinchao?  We should set IN_MEMORY true?  What else?
St.Ack