[ https://issues.apache.org/jira/browse/HADOOP-11327?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Eric Payne updated HADOOP-11327: -------------------------------- Target Version/s: 2.7.0 Status: Patch Available (was: Open) > BloomFilter#not() omits the last bit, resulting in an incorrect filter > ---------------------------------------------------------------------- > > Key: HADOOP-11327 > URL: https://issues.apache.org/jira/browse/HADOOP-11327 > Project: Hadoop Common > Issue Type: Bug > Components: util > Affects Versions: 2.5.1 > Reporter: Tim Luo > Assignee: Eric Payne > Priority: Minor > Attachments: HADOOP-11327.v1.txt > > > There's an off-by-one error in {{BloomFilter#not()}}: > {{BloomFilter#not}} calls {{BitSet#flip(0, vectorSize - 1)}}, but according > to the javadoc for that method, {{toIndex}} is end-_exclusive_: > {noformat} > * @param toIndex index after the last bit to flip > {noformat} > This means that the last bit in the bit array is not flipped. > Specifically, this was discovered in the following scenario: > 1. A new/empty {{BloomFilter}} was created with vectorSize=7. > 2. Invoke {{bloomFilter.not()}}; now expecting a bloom filter with all 7 bits > (0 through 6) flipped to 1 and membershipTest(...) to always return true. > 3. However, membershipTest(...) was found to often not return true, and upon > inspection, the BitSet only had bits 0 through 5 flipped. > The fix should be simple: remove the "- 1" from the call to {{BitSet#flip}}. -- This message was sent by Atlassian JIRA (v6.3.4#6332)