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https://issues.apache.org/jira/browse/HBASE-5877?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13262199#comment-13262199
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Zhihong Yu commented on HBASE-5877:
-----------------------------------
For RegionMovedException.java:
{code}
+ String tmpHostname = "nohostname";
{code}
I think the above could potentially be a host name :-)
{code}
+ } catch (Exception ignored) {
+ LOG.warn("Can't parse the hostname and the port from this string: " + s
+ ", "+
+ "Continuing");
+ }
{code}
Can we mark the failure and make this RegionMovedException behave the same as
NotServingRegionException ?
For updateCachedLocations(), please put explanation for parameter on the same
line as the parameter:
{code}
+ * @param row - row and tableName can be null id hrl is not null.
{code}
{code}
+ LOG.warn("Failed all from " + loc, e);
{code}
'Failed all' -> 'Failed call'
{code}
+ if (resp == null) {
+ // Entire server failed
+ LOG.fatal("Failed all for server: " + loc.getHostnamePort() +
+ ", removing from cache");
+ continue;
+ }
{code}
How is the server removed from cache since I see 'continue' above ?
{code}
+ } else {
+ if (numRetries == 1)
+ LOG.fatal("step 4 got result " + regionResult.getFirst() + "
" + regionResult.getSecond());
{code}
Why is the above fatal (regionResult != null) ? Step 4 appears in a comment
below the above code. Should the above say step 3 ?
Please increase the VERSION of HRegionInterface
{code}
+ * @param destServerName: server name on which the server will be moved
{code}
'which the server' -> 'which the region'
For ServerManager.sendRegionClose(), please add javadoc for destServerName
param.
For HRegionServer.java:
{code}
+ LOG.info("Closing region "+region.getRegionName()+", moving to
"+sn.getServerName() );
{code}
Is it possible that destServerName is null ?
{code}
+ private ServerName getMovedRegion(String encodedRegionName) {
+ LOG.fatal("Called getMovedRegion for "+encodedRegionName+" "+
movedRegions.size()+ " "+movedRegions);
{code}
Please change the above to debug log.
> When a query fails because the region has moved, let the regionserver return
> the new address to the client
> ----------------------------------------------------------------------------------------------------------
>
> Key: HBASE-5877
> URL: https://issues.apache.org/jira/browse/HBASE-5877
> Project: HBase
> Issue Type: Improvement
> Components: client, master, regionserver
> Affects Versions: 0.96.0
> Reporter: nkeywal
> Assignee: nkeywal
> Priority: Minor
> Fix For: 0.96.0
>
> Attachments: 5877.v1.patch
>
>
> This is mainly useful when we do a rolling restart. This will decrease the
> load on the master and the network load.
> Note that a region is not immediately opened after a close. So:
> - it seems preferable to wait before retrying on the other server. An
> optimisation would be to have an heuristic depending on when the region was
> closed.
> - during a rolling restart, the server moves the regions then stops. So we
> may have failures when the server is stopped, and this patch won't help.
> The implementation in the first patch does:
> - on the region move, there is an added parameter on the regionserver#close
> to say where we are sending the region
> - the regionserver keeps a list of what was moved. Each entry is kept 100
> seconds.
> - the regionserver sends a specific exception when it receives a query on a
> moved region. This exception contains the new address.
> - the client analyses the exeptions and update its cache accordingly...
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