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Posted to dev@hbase.apache.org by Stephen Jiang <sy...@gmail.com> on 2016/09/06 18:31:17 UTC

info:sn and info:server in hbase:meta table

I scanned the hbase:meta table in a fresh-build master branch and get the
following results.  Seems to me that info:sn and info:server are some kind
of duplicate (well, info:sn has the timestamp of RS, we could store this in
info:server too if we want).  Searching the code in master branch, I saw
some comment on "info:server", but could not find any information on
"info:sn".  Is this "info:sn" legacy information?  If so, for a new 2.0
cluster, should we not create the value in meta?

hbase(main):002:0> scan 'hbase:meta'
ROW
                 COLUMN+CELL
 hbase:meta
                 column=table:state, timestamp=1473185666041, value=\x08\x00
 hbase:namespace
                  column=table:state, timestamp=1473185667442,
value=\x08\x00
 hbase:namespace,,1473185666375.4c7fc12f243854e0af6c9e30ce7d6d90.
                 column=info:regioninfo, timestamp=1473185667273,
value={ENCODED => 4c7fc12f243854e0af6c9e30ce7d6d90, NAME =>
'hbase:namespace,,1473185666375.4c7fc12f243854e0af6c9e30ce7d6d90.',
STARTKEY => '', ENDKEY => ''}
 hbase:namespace,,1473185666375.4c7fc12f243854e0af6c9e30ce7d6d90.
                 column=info:seqnumDuringOpen, timestamp=1473185667603,
value=\x00\x00\x00\x00\x00\x00\x00\x02
 hbase:namespace,,1473185666375.4c7fc12f243854e0af6c9e30ce7d6d90.
                 column=info:server, timestamp=1473185667603, value=
10.22.2.122:58498
 hbase:namespace,,1473185666375.4c7fc12f243854e0af6c9e30ce7d6d90.
                 column=info:serverstartcode, timestamp=1473185667603,
value=1473185651426
 hbase:namespace,,1473185666375.4c7fc12f243854e0af6c9e30ce7d6d90.
                 column=info:sn, timestamp=1473185667421,
value=10.22.2.122,58498,1473185651426
 hbase:namespace,,1473185666375.4c7fc12f243854e0af6c9e30ce7d6d90.
                 column=info:state, timestamp=1473185667610, value=OPEN
3 row(s)

Re: info:sn and info:server in hbase:meta table

Posted by Enis Söztutar <en...@apache.org>.

From javadoc:

  /**

   * The serverName column qualifier. Its the server where the region is

   * transitioning on, while column server is the server where the region is

   * opened on. They are the same when the region is in state OPEN.

   */

  public static final String SERVERNAME_QUALIFIER_STR = "sn";


We could rename the column to be more explanatory, but we have already
released the code that serializes in this column, so may not be worth the
trouble.



On Tue, Sep 6, 2016 at 11:31 AM, Stephen Jiang <sy...@gmail.com>
wrote:

> I scanned the hbase:meta table in a fresh-build master branch and get the
> following results.  Seems to me that info:sn and info:server are some kind
> of duplicate (well, info:sn has the timestamp of RS, we could store this in
> info:server too if we want).  Searching the code in master branch, I saw
> some comment on "info:server", but could not find any information on
> "info:sn".  Is this "info:sn" legacy information?  If so, for a new 2.0
> cluster, should we not create the value in meta?
>
> hbase(main):002:0> scan 'hbase:meta'
> ROW
>                  COLUMN+CELL
>  hbase:meta
>                  column=table:state, timestamp=1473185666041,
> value=\x08\x00
>  hbase:namespace
>                   column=table:state, timestamp=1473185667442,
> value=\x08\x00
>  hbase:namespace,,1473185666375.4c7fc12f243854e0af6c9e30ce7d6d90.
>                  column=info:regioninfo, timestamp=1473185667273,
> value={ENCODED => 4c7fc12f243854e0af6c9e30ce7d6d90, NAME =>
> 'hbase:namespace,,1473185666375.4c7fc12f243854e0af6c9e30ce7d6d90.',
> STARTKEY => '', ENDKEY => ''}
>  hbase:namespace,,1473185666375.4c7fc12f243854e0af6c9e30ce7d6d90.
>                  column=info:seqnumDuringOpen, timestamp=1473185667603,
> value=\x00\x00\x00\x00\x00\x00\x00\x02
>  hbase:namespace,,1473185666375.4c7fc12f243854e0af6c9e30ce7d6d90.
>                  column=info:server, timestamp=1473185667603, value=
> 10.22.2.122:58498
>  hbase:namespace,,1473185666375.4c7fc12f243854e0af6c9e30ce7d6d90.
>                  column=info:serverstartcode, timestamp=1473185667603,
> value=1473185651426
>  hbase:namespace,,1473185666375.4c7fc12f243854e0af6c9e30ce7d6d90.
>                  column=info:sn, timestamp=1473185667421,
> value=10.22.2.122,58498,1473185651426
>  hbase:namespace,,1473185666375.4c7fc12f243854e0af6c9e30ce7d6d90.
>                  column=info:state, timestamp=1473185667610, value=OPEN
> 3 row(s)
>