distributedlog-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Sijie Guo <si...@apache.org>
Subject Re: Duplicate transaction ids
Date Mon, 26 Sep 2016 14:32:51 GMT
On Wed, Sep 21, 2016 at 2:17 AM, Leigh Stewart <lstewart@twitter.com.invalid
> wrote:

> >
> > Perhaps they are not equivalent or perhaps I have the wrong idea?
>
>
> They are not equivalent. Txnid is just a handy user defined sequence id.
>
> The unique id is the DLSN. Uniqueness of this id is guaranteed by DLOG.
>
> Thx
>
> On Tue, Sep 20, 2016 at 11:01 AM, john.lonergan <john.lonergan@gmail.com>
> wrote:
>
> > My quotation was raised because there was another discussion that
> resulted
> > in the answer  that  the txn Id was equiv to the index in raft.  However
> i
> > recall something about  uniqueness  as well as upwards-only being
> important
> > in raft around "stage machine safety " and "log matching"
> > Perhaps they are not equivalent or perhaps I have the wrong idea?
>

Sequence ID is the equiv to the index in raft.

Both DLSN and Sequence ID are system generated.

Transaction ID is user provided.


> > Any idea which way it is?
> > Thanks
> > -------- Original message --------From: Leigh Stewart
> > <lstewart@twitter.com.INVALID> Date: 20/09/2016  18:48  (GMT+00:00) To:
> > dev@distributedlog.incubator.apache.org Subject: Re: Duplicate
> > transaction ids
> > It simply must be non-decreasing- dup ids are ok.
> >
> > Since txid is used for positioning, if you had a long series of identical
> > txids you might have to scan through a lot of records to find the record
> > you were really looking for if you were doing a lookup. Other than that
> > there should be no impact.
> >
> > Thx
> >
> > On Tue, Sep 20, 2016 at 10:37 AM, john.lonergan <john.lonergan@gmail.com
> >
> > wrote:
> >
> > > Docs say the txn Id is  an application supplied sequence number. It is
> > > required to be non-decreasing. Users usually use either timestamp or
> > offset.
> > > What are  the consequences of publishing two consecutive messages with
> > the
> > > same txn ids.
> > >
> >
>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message