Github user afine commented on a diff in the pull request:
https://github.com/apache/zookeeper/pull/411#discussion_r147883484
--- Diff:
src/java/main/org/apache/zookeeper/server/quorum/CommitProcessor.java ---
@@ -255,24 +255,23 @@ public void run() {
// If session queue != null, then it is also not
empty.
Request topPending = sessionQueue.poll();
if (request.cxid != topPending.cxid) {
- LOG.error(
- "Got cxid 0x"
- +
Long.toHexString(request.cxid)
- + " expected 0x" +
Long.toHexString(
- topPending.cxid)
- + " for client session id "
- + Long.toHexString(request.sessionId));
- throw new IOException("Error: unexpected cxid
for"
- + "client session");
+ // we can get commit requests that are not at
the queue head after
+ // a session moved (see ZOOKEEPER-2684). We
will just pass the
+ // commit to the next processor and put the
pending back with
+ // a warning, we should not see this often
under normal load
+ LOG.warn("Got request " + request +
+ " but we are expecting request " +
topPending);
+ sessionQueue.addFirst(topPending);
+ } else {
+ /*
+ * We want to send our version of the request.
the
+ * pointer to the connection in the request
+ */
+ topPending.setHdr(request.getHdr());
--- End diff --
Would you mind explaining why we normally want to send our version of the
request and why it is ok not to in this case?
---
