Index: src/main/java/org/apache/hadoop/hbase/regionserver/Store.java =================================================================== --- src/main/java/org/apache/hadoop/hbase/regionserver/Store.java (revision 1499959) +++ src/main/java/org/apache/hadoop/hbase/regionserver/Store.java (working copy) @@ -2447,7 +2447,9 @@ * the number defined in minFilesToCompact */ public boolean needsCompaction() { - return (storefiles.size() - filesCompacting.size()) > minFilesToCompact; + synchronized (filesCompacting) { + return (storefiles.size() - filesCompacting.size()) > minFilesToCompact; + } } /**