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https://issues.apache.org/jira/browse/HBASE-17302?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Anoop Sam John reopened HBASE-17302:
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> The region flush request disappeared from flushQueue
> ----------------------------------------------------
>
> Key: HBASE-17302
> URL: https://issues.apache.org/jira/browse/HBASE-17302
> Project: HBase
> Issue Type: Bug
> Affects Versions: 2.0.0, 0.98.23, 1.2.4
> Reporter: Guangxu Cheng
> Assignee: Guangxu Cheng
> Fix For: 2.0.0, 1.4.0
>
> Attachments: HBASE-17302-branch-1-addendum-v1.patch,
> HBASE-17302-branch-1-addendum.patch, HBASE-17302-branch-1.2-v1.patch,
> HBASE-17302-branch-master-v1.patch, HBASE-17302-master-addendum-v1.patch,
> HBASE-17302-master-addendum.patch
>
>
> Region has too many store files delaying flush up to blockingWaitTime ms, and
> the region flush request is requeued into the flushQueue.
> When the region flush request is requeued into the flushQueue frequently, the
> request is inexplicably disappeared sometimes.
> But regionsInQueue still contains the information of the region request,
> which leads to new flush request can not be inserted into the flushQueue.
> Then, the region will not do flush anymore.
> In order to locate the problem, I added a lot of log in the code.
> {code:title=MemStoreFlusher.java|borderStyle=solid}
> private boolean flushRegion(final HRegion region, final boolean
> emergencyFlush) {
> long startTime = 0;
> synchronized (this.regionsInQueue) {
> FlushRegionEntry fqe = this.regionsInQueue.remove(region);
> // Use the start time of the FlushRegionEntry if available
> if (fqe != null) {
> startTime = fqe.createTime;
> }
> if (fqe != null && emergencyFlush) {
> // Need to remove from region from delay queue. When NOT an
> // emergencyFlush, then item was removed via a flushQueue.poll.
> flushQueue.remove(fqe);
> }
> }
> {code}
> When encountered emergencyFlush, the region flusher will be removed from the
> flushQueue.
> By comparing the flushQueue content before and after remove, RegionA should
> have been removed, it is possible to remove RegionB.
> {code:title=MemStoreFlusher.java|borderStyle=solid}
> public boolean equals(Object obj) {
> if (this == obj) {
> return true;
> }
> if (obj == null || getClass() != obj.getClass()) {
> return false;
> }
> Delayed other = (Delayed) obj;
> return compareTo(other) == 0;
> }
> {code}
> FlushRegionEntry in achieving the equals function, only comparison of the
> delay time, if different regions of the same delay time, it is possible that
> A wrong B.
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