Re: client thread stuck on HBaseClient.call

Fri, 13 Jan 2012 15:03:44 -0800 

It always hangs waiting on the same record....


On 13/01/12 22:48, Joel Halbert wrote:
Successfully got a few thousand results....nothing exceptional in the hbase log:
|2012-01-13 22:42:13,830 INFO org.apache.hadoop.io.compress.CodecPool: Got brand-new decompressor 2012-01-13 22:42:13,832 INFO org.apache.hadoop.io.compress.CodecPool: Got brand-new decompressor 2012-01-13 22:42:32,580 DEBUG org.apache.hadoop.hbase.io.hfile.LruBlockCache: LRUStats: total=332.03 MB, free=61.32 MB, max=393.35 MB, blocks=1524, accesses=720942, hits=691565, hitRatio=95.92%%, cachingAccesses=720938, cachingHits=691565, cachingHitsRatio=95.92%%, evictions=149, evicted=27849, evictedPerRun=186.90603637695312 2012-01-13 22:42:36,222 DEBUG org.apache.hadoop.hbase.master.LoadBalancer: Server information: localhost.localdomain,59902,1326492448413=15 2012-01-13 22:42:36,223 INFO org.apache.hadoop.hbase.master.LoadBalancer: Skipping load balancing. servers=1 regions=15 average=15.0 mostloaded=15 leastloaded=15 2012-01-13 22:42:36,236 DEBUG org.apache.hadoop.hbase.master.CatalogJanitor: Scanned 14 catalog row(s) and gc'd0 unreferenced parent region(s)| 



On 13/01/12 22:46, T Vinod Gupta wrote:

did u get any scan results at all?
check your region server and master hbase logs for any warnings..

also, just fyi - the standalone version of hbase is not super stable. i
have had many similar problems in the past. the distributed mode is much
much robust.

thanks
On Fri, Jan 13, 2012 at 2:36 PM, Joel Halbert<[email protected]> wrote: 


I have a standalone instance of HBASE (single instance, on localhost).

After reading a few thousand records using a scanner my thread is stuck
waiting:

"main" prio=10 tid=0x00000000016d4800 nid=0xf3a in Object.wait()
[0x00007fbe96dc3000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    at java.lang.Object.wait(Object.**java:503)
    at org.apache.hadoop.hbase.ipc.**HBaseClient.call(HBaseClient.**
java:757)
    - locked<0x00000007e2ba21d0>  (a org.apache.hadoop.hbase.ipc.**
HBaseClient$Call)
    at org.apache.hadoop.hbase.ipc.**HBaseRPC$Invoker.invoke(**
HBaseRPC.java:257)
    at $Proxy4.next(Unknown Source)
    at org.apache.hadoop.hbase.**client.ScannerCallable.call(**
ScannerCallable.java:79)
    at org.apache.hadoop.hbase.**client.ScannerCallable.call(**
ScannerCallable.java:38)
    at org.apache.hadoop.hbase.**client.HConnectionManager$**
HConnectionImplementation.**getRegionServerWithRetries(**
HConnectionManager.java:1019)
    at org.apache.hadoop.hbase.**client.MetaScanner.metaScan(**
MetaScanner.java:182)
    at org.apache.hadoop.hbase.**client.MetaScanner.metaScan(**
MetaScanner.java:95)
    at org.apache.hadoop.hbase.**client.HConnectionManager$**
HConnectionImplementation.**prefetchRegionCache(**
HConnectionManager.java:649)
    at org.apache.hadoop.hbase.**client.HConnectionManager$**
HConnectionImplementation.**locateRegionInMeta(**
HConnectionManager.java:703)
    - locked<0x00000007906dfcf8>  (a java.lang.Object)
    at org.apache.hadoop.hbase.**client.HConnectionManager$**
HConnectionImplementation.**locateRegion(**HConnectionManager.java:594)
    at org.apache.hadoop.hbase.**client.HConnectionManager$**
HConnectionImplementation.**locateRegion(**HConnectionManager.java:559)
    at org.apache.hadoop.hbase.**client.HConnectionManager$**
HConnectionImplementation.**getRegionLocation(**
HConnectionManager.java:416)
at org.apache.hadoop.hbase.**client.ServerCallable.**instantiateServer( 
**ServerCallable.java:57)
    at org.apache.hadoop.hbase.**client.ScannerCallable.**
instantiateServer(**ScannerCallable.java:63)
    at org.apache.hadoop.hbase.**client.HConnectionManager$**
HConnectionImplementation.**getRegionServerWithRetries(**
HConnectionManager.java:1018)
    at org.apache.hadoop.hbase.**client.HTable$ClientScanner.**
nextScanner(HTable.java:1104)
    at org.apache.hadoop.hbase.**client.HTable$ClientScanner.**
next(HTable.java:1196)
    at org.apache.hadoop.hbase.**client.HTable$ClientScanner$1.**
hasNext(HTable.java:1256)
    at crawler.cache.PageCache.**accept(PageCache.java:254)



Concretely, it is stuck on the iterator.next method:

        Scan scan = new Scan(Bytes.toBytes(**hostnameTarget),
Bytes.toBytes(hostnameTarget + (char) 127));
        scan.setMaxVersions(1);
        scan.setCaching(4);
        ResultScanner resscan = table.getScanner(scan);
        Iterator<Result>  it = resscan.iterator();
        while (it.hasNext()) {              // stuck here



Any clues?

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