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From Bob Cook <>
Subject Re: Fwd: Extacting ALL Data using multiple java processes
Date Mon, 17 Oct 2016 02:10:15 GMT

Thanks. I was able to get TimestampFilter to works for my needs.  But I
originally wanted "createdDate" as our application creates that date which
is known to the user
and may be different than accumulo timestamp due to when the data actually
got processed into accumulo.

So if I wanted to use the ColumnFamily "createdDate" and it's value,  what
java code would I have to write?

I looked at the AccumuloInputFormat class, but confused on how to specify
the "range" for the date range that I'm interested in..

So would I use the TimestampFilter Class similar to how I'm using it in the
"scanner.addScanIterator", but instead using
"AcculoInputFormat.addIterator(job, is), as below.

IteratorSetting is = new IteratorSetting(30, TimestampFilter.class);
TimestampFilter.setRange(is, startDate, endDate);
AccumuloInputFormat.addIterator(job, is);

Or could I use
is.addOption("start", startDate);
is.addOption("end", endDate);

NOTE: for me "TimestempFilter.setRange"  nor "TimestampFilter.setStart and
TimestampFilter.setEnd didn't seem to work.

On Sun, Oct 16, 2016 at 2:05 PM, Josh Elser <> wrote:

> The TimestampFilter will return only the Keys whose timestamp fall in the
> range you specify. The timestamp is an attribute on every Key, a long value
> which, when not set by the client at write time, is the number of millis
> since the epoch. You specify the numeric range of timestamps you want. This
> is a post-filter operation -- Accumulo must still read all of the data in
> the table.
> You need to tell *us* what the time component you're actually filtering
> on: the timestamp on each Key, or the createdDate column in each row.
> MapReduce is likely more efficient to do this batch processing (as
> MapReduce is a batch processing system). See the AccumuloInputFormat class.
> Bob Cook wrote:
>> All,
>> I'm new to accumulo and inherited this project to extract all data from
>> accumulo (assembled as a "document" by RowID) into another web service.
>> So I started with to "scan" all data, and built a
>> "document" based on the RowID, ColumnFamily and Value. Sending
>> this "document" to the service.
>> Example data.
>> RowID_1 createdDate "2015-01-01:00:00:01 UTC"
>> RowID_1 data "this is a test"
>> RowID_1 title "My test title"
>> RowID_2 createdDate "2015-01-01:12:01:01 UTC"
>> RowID_2 data "this is test 2"
>> RowID_2 title "My test2 title"
>> ...
>> So my table is pretty simple,  RowID, ColumnFamily and Value (no
>> ColumnQualifier)
>> I need to process one Billion "OLD" unique RowIDs (a years worth of
>> data) on a live system that is ingesting "new data" at a rate of about a
>> 4million RowIds a day.
>> i.e. I need to process data from September 2015 - September 2016, not
>> worrying about new data coming in.
>> So I'm thinking I need to run multiple processes to extract ALL the data
>> in this "data range" to be more efficient.
>> Also, it may allow me to run the processes at a lower priority and at
>> off-hours of the day when traffic is less.
>> My issue is how do I specify the "range" to scan, and how do I specify.
>> 1. Is using the "createdDate" a good idea, if so how would I specify the
>> range for it.
>> 2. How about the TimestampFilter?   If I specify my start to end to
>> "equal" a day (about 4 Million unique RowIDs),
>> Will this get me all ColumnFamily and Values for a given RowID?  Or
>> could I miss something because it's timestamp
>> was the next day.  I don't really understand Timestamps wrt Accumulo.
>> 3. Does a map-reduce job make sense.  If so, how would I specify.
>> Thanks,
>> Bob

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