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https://issues.apache.org/jira/browse/HBASE-4351?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13100541#comment-13100541
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Jean-Daniel Cryans commented on HBASE-4351:
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Well there's definitely something we need to do. For example the shell help
says:
bq. Pass 'true' to force the unassignment ('force' will clear all in-memory
state in master before the reassign).
This doesn't make sense since you can't wipe out the in-memory state, and then
know where to unassign (you just wiped that). Maybe we could do something
better since we're not going to send a close... like I mentioned, I have to
hbck -fix to reassign the region after using this, maybe we could call assign
in the unassign method when force=true?
I know it sounds dumb, but in the end that's what happens anyway when you
unassign with force=false because when the master receives the notification
that the region is closed then it reassigns it.
> If from Admin we try to unassign a region forcefully, though a valid region
> name is given the master is not able to identify the region to unassign.
> ----------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: HBASE-4351
> URL: https://issues.apache.org/jira/browse/HBASE-4351
> Project: HBase
> Issue Type: Bug
> Environment: Linux
> Reporter: ramkrishna.s.vasudevan
> Assignee: ramkrishna.s.vasudevan
>
> The following is the problem
> Get the exact region name from UI and call
> HBaseAdmin.unassign(regionname, true).
> Here true is forceful option.
> As part of unassign api
> {code}
> public void unassign(final byte [] regionName, final boolean force)
> throws IOException {
> Pair<HRegionInfo, HServerAddress> pair =
> MetaReader.getRegion(this.catalogTracker, regionName);
> if (pair == null) throw new
> UnknownRegionException(Bytes.toStringBinary(regionName));
> HRegionInfo hri = pair.getFirst();
> if (force) this.assignmentManager.clearRegionFromTransition(hri);
> this.assignmentManager.unassign(hri, force);
> }
> {code}
> As part of clearRegionFromTransition()
> {code}
> synchronized (this.regions) {
> this.regions.remove(hri);
> for (Set<HRegionInfo> regions : this.servers.values()) {
> regions.remove(hri);
> }
> }
> {code}
> the region is also removed. Hence when the master tries to identify the
> region
> {code}
> if (!regions.containsKey(region)) {
> debugLog(region, "Attempted to unassign region " +
> region.getRegionNameAsString() + " but it is not " +
> "currently assigned anywhere");
> return;
> }
> {code}
> It is not able to identify the region. It exists in trunk and 0.90.x also.
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