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Posted to dev@hbase.apache.org by chunping rao <an...@gmail.com> on 2009/08/18 12:18:25 UTC
MAX_SEQ_ID_KEY in StoreFile
hi:
all
in the source code of hbase-0.20.0,i can't understand the use of the
attribute "MAX_SED_ID_KEY" ,what is the role of "MAX_SEQ_ID_KEY"?
Re: MAX_SEQ_ID_KEY in StoreFile
Posted by Anty <an...@gmail.com>.
@stack
Helpfull!
Thank you very much!
2009/8/19 stack <st...@duboce.net>
> Thanks. I missed it grepping.
>
> Each hfile has written into its metadata its maximums sequence (edit)
> number
> -- the sequence id of its last entry. MAX_SEQ_ID_KEY is the key used
> writing this attribute into the hfile metadata map.
>
> St.Ack
>
>
>
> On Tue, Aug 18, 2009 at 9:55 AM, chunping rao <an...@gmail.com> wrote:
>
> > hi:
> > stack
> > MAX_SEQ_ID_KEY is in the StoreFile.java of package
> > org.apache.hadoop.hbase.regionserver.....Sorry ,i do not known exactly
> the
> > version of my hbase.
> >
> >
> > 2009/8/19 stack <st...@duboce.net>
> >
> > > Oops. Sorry. Answered wrong question.
> > >
> > > I grepped source in 0.19 and 0.20 branches and don't see
> MAX_SEQ_ID_KEY.
> > > Where are you seeing that?
> > >
> > > Thanks,
> > > St.Ack
> > >
> > >
> > >
> > > On Tue, Aug 18, 2009 at 9:43 AM, stack <st...@duboce.net> wrote:
> > >
> > > > On each edit, a sequence id is incremented. When edits are applied
> to
> > > the
> > > > commit log their sequence id is noted along with the entry. When we
> > > flush,
> > > > the sequence id of the flushed edits are noted in the flush/store
> file.
> > > The
> > > > regionserver will let go of commit logs (hlogs in hbase parlance) if
> > all
> > > its
> > > > edits have been flushed to the filesystem. It uses the sequence id
> > > figuring
> > > > when it can do this. Sequence id is also used figuring which of a
> set
> > of
> > > > flush/store files is the newer (the file denoted by the larger
> sequence
> > > id
> > > > will be newer) among other things.
> > > >
> > > > Does this help?
> > > >
> > > > St.Ack
> > > >
> > > >
> > > > On Tue, Aug 18, 2009 at 3:18 AM, chunping rao <an...@gmail.com>
> > > wrote:
> > > >
> > > >> hi:
> > > >> all
> > > >> in the source code of hbase-0.20.0,i can't understand the use of
> > the
> > > >> attribute "MAX_SED_ID_KEY" ,what is the role of "MAX_SEQ_ID_KEY"?
> > > >>
> > > >
> > > >
> > >
> >
>
Re: MAX_SEQ_ID_KEY in StoreFile
Posted by stack <st...@duboce.net>.
Thanks. I missed it grepping.
Each hfile has written into its metadata its maximums sequence (edit) number
-- the sequence id of its last entry. MAX_SEQ_ID_KEY is the key used
writing this attribute into the hfile metadata map.
St.Ack
On Tue, Aug 18, 2009 at 9:55 AM, chunping rao <an...@gmail.com> wrote:
> hi:
> stack
> MAX_SEQ_ID_KEY is in the StoreFile.java of package
> org.apache.hadoop.hbase.regionserver.....Sorry ,i do not known exactly the
> version of my hbase.
>
>
> 2009/8/19 stack <st...@duboce.net>
>
> > Oops. Sorry. Answered wrong question.
> >
> > I grepped source in 0.19 and 0.20 branches and don't see MAX_SEQ_ID_KEY.
> > Where are you seeing that?
> >
> > Thanks,
> > St.Ack
> >
> >
> >
> > On Tue, Aug 18, 2009 at 9:43 AM, stack <st...@duboce.net> wrote:
> >
> > > On each edit, a sequence id is incremented. When edits are applied to
> > the
> > > commit log their sequence id is noted along with the entry. When we
> > flush,
> > > the sequence id of the flushed edits are noted in the flush/store file.
> > The
> > > regionserver will let go of commit logs (hlogs in hbase parlance) if
> all
> > its
> > > edits have been flushed to the filesystem. It uses the sequence id
> > figuring
> > > when it can do this. Sequence id is also used figuring which of a set
> of
> > > flush/store files is the newer (the file denoted by the larger sequence
> > id
> > > will be newer) among other things.
> > >
> > > Does this help?
> > >
> > > St.Ack
> > >
> > >
> > > On Tue, Aug 18, 2009 at 3:18 AM, chunping rao <an...@gmail.com>
> > wrote:
> > >
> > >> hi:
> > >> all
> > >> in the source code of hbase-0.20.0,i can't understand the use of
> the
> > >> attribute "MAX_SED_ID_KEY" ,what is the role of "MAX_SEQ_ID_KEY"?
> > >>
> > >
> > >
> >
>
Re: MAX_SEQ_ID_KEY in StoreFile
Posted by chunping rao <an...@gmail.com>.
hi:
stack
MAX_SEQ_ID_KEY is in the StoreFile.java of package
org.apache.hadoop.hbase.regionserver.....Sorry ,i do not known exactly the
version of my hbase.
2009/8/19 stack <st...@duboce.net>
> Oops. Sorry. Answered wrong question.
>
> I grepped source in 0.19 and 0.20 branches and don't see MAX_SEQ_ID_KEY.
> Where are you seeing that?
>
> Thanks,
> St.Ack
>
>
>
> On Tue, Aug 18, 2009 at 9:43 AM, stack <st...@duboce.net> wrote:
>
> > On each edit, a sequence id is incremented. When edits are applied to
> the
> > commit log their sequence id is noted along with the entry. When we
> flush,
> > the sequence id of the flushed edits are noted in the flush/store file.
> The
> > regionserver will let go of commit logs (hlogs in hbase parlance) if all
> its
> > edits have been flushed to the filesystem. It uses the sequence id
> figuring
> > when it can do this. Sequence id is also used figuring which of a set of
> > flush/store files is the newer (the file denoted by the larger sequence
> id
> > will be newer) among other things.
> >
> > Does this help?
> >
> > St.Ack
> >
> >
> > On Tue, Aug 18, 2009 at 3:18 AM, chunping rao <an...@gmail.com>
> wrote:
> >
> >> hi:
> >> all
> >> in the source code of hbase-0.20.0,i can't understand the use of the
> >> attribute "MAX_SED_ID_KEY" ,what is the role of "MAX_SEQ_ID_KEY"?
> >>
> >
> >
>
Re: MAX_SEQ_ID_KEY in StoreFile
Posted by stack <st...@duboce.net>.
Oops. Sorry. Answered wrong question.
I grepped source in 0.19 and 0.20 branches and don't see MAX_SEQ_ID_KEY.
Where are you seeing that?
Thanks,
St.Ack
On Tue, Aug 18, 2009 at 9:43 AM, stack <st...@duboce.net> wrote:
> On each edit, a sequence id is incremented. When edits are applied to the
> commit log their sequence id is noted along with the entry. When we flush,
> the sequence id of the flushed edits are noted in the flush/store file. The
> regionserver will let go of commit logs (hlogs in hbase parlance) if all its
> edits have been flushed to the filesystem. It uses the sequence id figuring
> when it can do this. Sequence id is also used figuring which of a set of
> flush/store files is the newer (the file denoted by the larger sequence id
> will be newer) among other things.
>
> Does this help?
>
> St.Ack
>
>
> On Tue, Aug 18, 2009 at 3:18 AM, chunping rao <an...@gmail.com> wrote:
>
>> hi:
>> all
>> in the source code of hbase-0.20.0,i can't understand the use of the
>> attribute "MAX_SED_ID_KEY" ,what is the role of "MAX_SEQ_ID_KEY"?
>>
>
>
Re: MAX_SEQ_ID_KEY in StoreFile
Posted by stack <st...@duboce.net>.
On each edit, a sequence id is incremented. When edits are applied to the
commit log their sequence id is noted along with the entry. When we flush,
the sequence id of the flushed edits are noted in the flush/store file. The
regionserver will let go of commit logs (hlogs in hbase parlance) if all its
edits have been flushed to the filesystem. It uses the sequence id figuring
when it can do this. Sequence id is also used figuring which of a set of
flush/store files is the newer (the file denoted by the larger sequence id
will be newer) among other things.
Does this help?
St.Ack
On Tue, Aug 18, 2009 at 3:18 AM, chunping rao <an...@gmail.com> wrote:
> hi:
> all
> in the source code of hbase-0.20.0,i can't understand the use of the
> attribute "MAX_SED_ID_KEY" ,what is the role of "MAX_SEQ_ID_KEY"?
>