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https://issues.apache.org/jira/browse/HBASE-7525?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13646553#comment-13646553
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Matteo Bertozzi commented on HBASE-7525:
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thanks for the quick follow-up
to make the Hadoop QA happy, use "git diff > HBASE-XYZ.patch"
(see the "unable to apply patch" error above)
for the getStartKey() you're right, it's not null but even an empty byte array
doesn't pass the test. Mutation.checkRow() throws an exception on length == 0
{code}
java.lang.IllegalArgumentException: Row length is 0
at org.apache.hadoop.hbase.client.Mutation.checkRow(Mutation.java:335)
at org.apache.hadoop.hbase.client.Mutation.checkRow(Mutation.java:319)
at org.apache.hadoop.hbase.client.Get.<init>(Get.java:86)
at
org.apache.hadoop.hbase.tool.Canary$RegionMonitor.sniffRegion(Canary.java:483)
at
org.apache.hadoop.hbase.tool.Canary$RegionMonitor.sniff(Canary.java:463)
at
org.apache.hadoop.hbase.tool.Canary$RegionMonitor.sniff(Canary.java:433)
at
org.apache.hadoop.hbase.tool.Canary$RegionMonitor.run(Canary.java:380)
{code}
My simple test is this... and you get a misleading error on the first region
due to the empty key.
{code}
$ hbase shell
> create 'testtb', 'cf'
> put 'testtb', 'row0', 'cf:q', '0'
> put 'testtb', 'row1', 'cf:q', '1'
> put 'testtb', 'row2', 'cf:q', '2'
$ hbase org.apache.hadoop.hbase.tool.Canary
...
2013-05-01 13:58:50,310 ERROR [Thread-0] tool.Canary: read from region
testtb,,1367412865960.99b4d7e3b71c1f5292bc96fad28bb67e. failed
{code}
also you may be useful to add at least a LOG.debug() with the exception inside
all the catch just to have an idea of what's going wrong (like the Get failure
above)
> A canary monitoring program specifically for regionserver
> ---------------------------------------------------------
>
> Key: HBASE-7525
> URL: https://issues.apache.org/jira/browse/HBASE-7525
> Project: HBase
> Issue Type: New Feature
> Components: monitoring
> Affects Versions: 0.94.0
> Reporter: takeshi.miao
> Priority: Minor
> Fix For: 0.95.0
>
> Attachments: HBASE-7525-0.95-v0.patch, HBASE-7525-0.95-v1.patch,
> HBASE-7525-v0.patch, RegionServerCanary.java
>
>
> *Motivation*
> This ticket is to provide a canary monitoring tool specifically for
> HRegionserver, details as follows
> 1. This tool is required by operation team due to they thought that the
> canary for each region of a HBase is too many for them, so I implemented this
> coarse-granular one based on the original o.a.h.h.tool.Canary for them
> 2. And this tool is implemented by multi-threading, which means the each Get
> request sent by a thread. the reason I use this way is due to we suffered the
> region server hung issue by now the root cause is still not clear. so this
> tool can help operation team to detect hung region server if any.
> *example*
> 1. the tool docs
> ./bin/hbase org.apache.hadoop.hbase.tool.RegionServerCanary -help
> Usage: [opts] [regionServerName 1 [regionServrName 2...]]
> regionServerName - FQDN serverName, can use linux command:hostname -f to
> check your serverName
> where [-opts] are:
> -help Show this help and exit.
> -e Use regionServerName as regular expression
> which means the regionServerName is regular expression pattern
> -f <B> stop whole program if first error occurs, default is true
> -t <N> timeout for a check, default is 600000 (milisecs)
> -daemon Continuous check at defined intervals.
> -interval <N> Interval between checks (sec)
> 2. Will send a request to each regionserver in a HBase cluster
> ./bin/hbase org.apache.hadoop.hbase.tool.RegionServerCanary
> 3. Will send a request to a regionserver by given name
> ./bin/hbase org.apache.hadoop.hbase.tool.RegionServerCanary rs1.domainname
> 4. Will send a request to regionserver(s) by given regular-expression
> /opt/trend/circus-opstool/bin/hbase-canary-monitor-each-regionserver.sh -e
> rs1.domainname.pattern
> // another example
> ./bin/hbase org.apache.hadoop.hbase.tool.RegionServerCanary -e
> tw-poc-tm-puppet-hdn[0-9]\{1,2\}.client.tw.trendnet.org
> 5. Will send a request to a regionserver and also set a timeout limit for
> this test
> // query regionserver:rs1.domainname with timeout limit 10sec
> // -f false, means that will not exit this program even test failed
> ./bin/hbase org.apache.hadoop.hbase.tool.RegionServerCanary -f false -t 10000
> rs1.domainname
> // echo "1" if timeout
> echo "$?"
> 6. Will run as daemon mode, which means it will send request to each
> regionserver periodically
> ./bin/hbase org.apache.hadoop.hbase.tool.RegionServerCanary -daemon
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