accumulo-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Josh Elser <>
Subject Re: admin and web dashboard
Date Mon, 08 Jun 2015 18:08:31 GMT
Right, you got it.

You can change the maxVersions many times but that won't be persisted on 
disk until a compaction rewrites that data. Scans will, however, always 
be consistent with the current configuration.

In the implementation, Accumulo will instantiate the current iterators 
for the minc or majc scope (depending on if it's a minor or major 
compaction) and write the output of memory/files being compacted, 
filtered/transformed by those iterators, back out to a single file.

z11373 wrote:
> Thanks Josh for the answers. I just have one clarification from the answer
> for #2.
> So let say we set the max version to keep is default value (in this case is
> 1), then after few inserts with same key, and we change the max version to
> 3. Based on what you said, if the compaction occurs before we change to 3,
> then we'll only see 1 row from scan (since all previous versions have been
> deleted), is that correct?
> If this is confirmed, then it looks like Accumulo is looking for that max
> version to keep value while doing compaction, so that it knows how many of
> previous versions need to be deleted, right?
> Thanks,
> Z
> --
> View this message in context:
> Sent from the Users mailing list archive at

View raw message