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Posted to dev@hbase.apache.org by Demai Ni <ni...@gmail.com> on 2014/04/18 23:27:11 UTC

a way to record # of rows 'deleted' due to TTL

hi, folks,

Understand that TTL plays its role in the background, I am wondering
whether there is a way to have some information of the retired rows?

for example,
1) 100 rows were put initially
2) during one day period, 2 rows was deleted by user, and 10 rows 'retired'
due to TTL

is there a way to figure out the '10'? Is there a way to plug in a
co-processor for that purpose?

Many thanks

Demai

Re: a way to record # of rows 'deleted' due to TTL

Posted by Demai Ni <ni...@gmail.com>.
Lars,

thanks a lot for the tip. seems not a straightforward one. I will look into
ExplicitColumnTracker and ScanQueryMatcher. I agree compaction time may be
a good idea.

Demai


On Fri, Apr 18, 2014 at 2:52 PM, lars hofhansl <la...@apache.org> wrote:

> There is no good way at the moment unless you handle it completely
> yourself via a coprocessor.
> I suppose we could add a metric...? Would that be good enough? Even that
> would not be entirely trivial to add into the bowls of the ColumnTrackers
> (wouldn't want to count it during normal scans but only in compactions).
>
>
> -- Lars
>
>
>
> ________________________________
>  From: Demai Ni <ni...@gmail.com>
> To: "dev@hbase.apache.org" <de...@hbase.apache.org>
> Sent: Friday, April 18, 2014 2:27 PM
> Subject: a way to record # of rows 'deleted' due to TTL
>
>
> hi, folks,
>
> Understand that TTL plays its role in the background, I am wondering
> whether there is a way to have some information of the retired rows?
>
> for example,
> 1) 100 rows were put initially
> 2) during one day period, 2 rows was deleted by user, and 10 rows 'retired'
> due to TTL
>
> is there a way to figure out the '10'? Is there a way to plug in a
> co-processor for that purpose?
>
> Many thanks
>
> Demai
>

Re: a way to record # of rows 'deleted' due to TTL

Posted by lars hofhansl <la...@apache.org>.
There is no good way at the moment unless you handle it completely yourself via a coprocessor.
I suppose we could add a metric...? Would that be good enough? Even that would not be entirely trivial to add into the bowls of the ColumnTrackers (wouldn't want to count it during normal scans but only in compactions).


-- Lars



________________________________
 From: Demai Ni <ni...@gmail.com>
To: "dev@hbase.apache.org" <de...@hbase.apache.org> 
Sent: Friday, April 18, 2014 2:27 PM
Subject: a way to record # of rows 'deleted' due to TTL
 

hi, folks,

Understand that TTL plays its role in the background, I am wondering
whether there is a way to have some information of the retired rows?

for example,
1) 100 rows were put initially
2) during one day period, 2 rows was deleted by user, and 10 rows 'retired'
due to TTL

is there a way to figure out the '10'? Is there a way to plug in a
co-processor for that purpose?

Many thanks

Demai