cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From liangfeng <>
Subject Re: Leveled Compaction in cassandra1.0 may not be perfect
Date Mon, 05 Dec 2011 01:38:37 GMT
Jonathan Ellis <jbellis <at>> writes:
> You should look at the org.apache.cassandra.db.compaction package and
> read the original leveldb implementation notes at
> for more
> details.
There is an important rule in
"We also switch to a new output file when the key range of the current output
file has grown enough to overlap more then ten level-(L+2) files. This last rule
ensures that a later compaction of a level-(L+1) file will not pick up too much
data from level-(L+2)." 
But in LeveledCompactionTask,we switch to a new output file just when the
sstable  reach to the fixed-size.So I don't think cassandra1.0 can avoid
unusually large compaction.

View raw message