Thanks for the comment Guozhang,

I just changed the configuration name to "time.index.interval.ms".

It seems the real question here is how big the offset indices will be.
Theoretically we can have one time index entry for each message in a log
segment. For example, if there is one event per minute appended, we might
have to have a time index entry for each message until the segment size is
reached. In that case, the number of index entries in the time index would
be (segment size / avg message size). So the time index file size can
potentially be big.

I am wondering if we can simply reuse the "index.interval.bytes"
configuration instead of having a separate time index interval ms. i.e.
instead of inserting a new entry based on time interval, we still insert it
based on bytes interval. This does not affect the granularity because we
can search from the nearest index entry to find the message with correct
timestamp. The good thing is that this guarantees there will not be huge
time indices. We also save the new configuration.

What do you think?

Thanks,

Jiangjie (Becket) Qin

On Wed, Feb 24, 2016 at 1:00 PM, Guozhang Wang <wangg...@gmail.com> wrote:

> Thanks Jiangjie, a few comments on the wiki:
>
> 1. Config name "time.index.interval" to "time.index.interval.ms" to be
> consistent. Also do we need a "time.index.size.max.bytes" as well?
>
> 2. Will the memory mapped index file for timestamp have the same default
> initial / max size (10485760) as the offset index?
>
> Otherwise LGTM.
>
> Guozhang
>
> On Tue, Feb 23, 2016 at 5:05 PM, Becket Qin <becket....@gmail.com> wrote:
>
> > Bump.
> >
> > Per Jun's comments during KIP hangout, I have updated wiki with the
> upgrade
> > plan or KIP-33.
> >
> > Let's vote!
> >
> > Thanks,
> >
> > Jiangjie (Becket) Qin
> >
> > On Wed, Feb 3, 2016 at 10:32 AM, Becket Qin <becket....@gmail.com>
> wrote:
> >
> > > Hi all,
> > >
> > > I would like to initiate the vote for KIP-33.
> > >
> > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-33
> > > +-+Add+a+time+based+log+index
> > >
> > > A good amount of the KIP has been touched during the discussion on
> > KIP-32.
> > > So I also put the link to KIP-32 here for reference.
> > > https://cwiki.apache.org/confluence/display/KAFKA/KIP
> > > -32+-+Add+timestamps+to+Kafka+message
> > >
> > > Thanks,
> > >
> > > Jiangjie (Becket) Qin
> > >
> >
>
>
>
> --
> -- Guozhang
>

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