accumulo-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Josh Elser <josh.el...@gmail.com>
Subject Re: Delete All Data In Table
Date Mon, 12 May 2014 14:34:26 GMT
On 5/12/14, 10:12 AM, BlackJack76 wrote:
> I am not familiar with the DevNullIterator.  I will have to look into that.

Ah, misspoke on the class name. Using the shell:

config -t your_table_name -s 
table.iterator.majc.devnull=21,org.apache.accumulo.core.iterators.DevNull
compact -t your_table_name -w

There's also a `wait` option on the compact method that you can use to 
programmatically compact the table and wait for it to finish.

The DevNull iterator, obviously, a pun on /dev/null which just consumes 
all data sent to it. This iterator will never return any data. We use it 
internally for development on Accumulo to benchmark the internals 
without being affected by disk speed. It is an "internal class", so just 
be aware that it might change out from underneath you across versions 
(but it hasn't since Accumulo has been in Apache, so you're probably 
going to be ok :D)

> Also, do you know if I could attach some sort of custom RowFilter to the
> table that would do the trick?

Possibly, but you'd pretty much just be reimplementing what DevNull is 
doing less efficiently because of the RowFilter constraints.

Making an org.apache.accumulo.core.iterators.users.DevNull iterator may 
be useful if you'd like to submit a patch. We could document it better 
giving some user-facing examples of when such a class would be useful.

Mime
View raw message