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Posted to issues@hbase.apache.org by "Jonathan Gray (JIRA)" <ji...@apache.org> on 2010/11/17 12:13:14 UTC
[jira] Updated: (HBASE-3243) Disable Table closed region on wrong
host
[ https://issues.apache.org/jira/browse/HBASE-3243?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Jonathan Gray updated HBASE-3243:
---------------------------------
Attachment: HBASE-3243-v1.patch
Fixes to {{regions}} synchronization including one misuse of {{servers}} modification under it's own lock rather than the {{regions}} lock.
Looking at this more, I'm not sure synchronization is the issue here because TreeMap appears to only be not thread-safe when there are mutations. The two critical pieces of code where a conflict could happen are where we read the server a region is assigned to, and where we set the server a region is assigned to.
AssignmentManager:525 in {{regionOnline()}}
{noformat}
synchronized (this.regions) {
// Add check
HServerInfo hsi = this.regions.get(regionInfo);
if (hsi != null) LOG.warn("Overwriting " + regionInfo.getEncodedName() +
" on " + hsi);
this.regions.put(regionInfo, serverInfo);
addToServers(serverInfo, regionInfo);
}
{noformat}
AssignmentManager:1008 in {{unassign()}}
{noformat}
synchronized (this.regions) {
server = regions.get(region);
}
{noformat}
Seems like this is okay as-is. We should definitely still apply this patch to fix the synchronization issues but I'm not sure it is the cause.
Digging more.
> Disable Table closed region on wrong host
> -----------------------------------------
>
> Key: HBASE-3243
> URL: https://issues.apache.org/jira/browse/HBASE-3243
> Project: HBase
> Issue Type: Bug
> Components: master
> Affects Versions: 0.90.0
> Reporter: Todd Lipcon
> Priority: Blocker
> Fix For: 0.90.0
>
> Attachments: HBASE-3243-v1.patch
>
>
> I ran some YCSB benchmarks which resulted in about 150 regions worth of data overnight. Then I disabled the table, and the master for some reason closed one region on the wrong server. The server ignored this, but the region remained open on a different server, which later flipped out when it tried to flush due to hlog accumulation.
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