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  1. ZooKeeper
  2. ZOOKEEPER-1622

session ids will be negative in the year 2022

    Details

    • Type: Bug
    • Status: Closed
    • Priority: Trivial
    • Resolution: Fixed
    • Affects Version/s: 3.4.0, 3.5.0
    • Fix Version/s: 3.4.6, 3.5.0
    • Component/s: None
    • Labels:
      None
    • Hadoop Flags:
      Reviewed

      Description

      Someone decided to use a large number for their myid file. This cause session ids to go negative, and our software (Apache Accumulo) did not handle this very well. While diagnosing the problem, I noticed this in SessionImpl:

         public static long initializeNextSession(long id) {
              long nextSid = 0;
              nextSid = (System.currentTimeMillis() << 24) >> 8;
              nextSid =  nextSid | (id <<56);
              return nextSid;
          }
      

      When the 40th bit in System.currentTimeMillis() is a one, sign extension will fill the upper 8 bytes of nextSid, and id will not make the session id unique. I recommend changing the right shift to the logical shift:

         public static long initializeNextSession(long id) {
              long nextSid = 0;
              nextSid = (System.currentTimeMillis() << 24) >>> 8;
              nextSid =  nextSid | (id <<56);
              return nextSid;
          }
      

      But, we have until the year 2022 before we have to worry about it.

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            • Assignee:
              ecn Eric Newton
              Reporter:
              ecn Eric Newton
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              • Created:
                Updated:
                Resolved: