Should this be added as a known issue in the CDH or hbase documentation? It was a severe performance hit for us, all of our regionservers were sitting at a few thousand queued requests.
On Mon, Nov 30, 2015 at 3:53 PM Bryan Beaudreault <bbeaudrea...@hubspot.com> wrote: > Yea, they are all over the place and called from client and coprocessor > code. We ended up having no other option but to rollback, and aside from a > few NoSuchMethodErrors due to API changes (Put#add vs Put#addColumn), it > seems to be working and fixing our problem. > > On Mon, Nov 30, 2015 at 3:47 PM Stack <st...@duboce.net> wrote: > >> Rollback is untested. No fix in 5.5. I was going to work on this now. >> Where >> are your counters Bryan? In their own column family or scattered about in >> a >> row with other Cell types? >> St.Ack >> >> On Mon, Nov 30, 2015 at 10:28 AM, Bryan Beaudreault < >> bbeaudrea...@hubspot.com> wrote: >> >> > Is there any update to this? We just upgraded all of our production >> > clusters from CDH4 to CDH5.4.7 and, not seeing this JIRA listed in the >> > known issues, did not not about this. Now we are seeing perfomance >> issues >> > across all clusters, as we make heavy use of increments. >> > >> > Can we roll forward to CDH5.5 to fix? Or is our only hope to roll back >> to >> > CDH 5.3.1 (if that is possible)? >> > >> > >> > On Thu, Sep 24, 2015 at 5:06 AM 鈴木俊裕 <brfrn...@gmail.com> wrote: >> > >> > > Thank you St.Ack! >> > > >> > > I would like to follow the ticket. >> > > >> > > Toshihiro Suzuki >> > > >> > > 2015-09-22 14:14 GMT+09:00 Stack <st...@duboce.net>: >> > > >> > > > Back to this problem. Simple tests confirm that as is, the >> > > > single-queue-backed MVCC instance can slow Region ops if some other >> row >> > > is >> > > > slow to complete. In particular Increment, checkAndPut, and batch >> > > mutations >> > > > are effected. I opened HBASE-14460 to start in on a fix up. Lets >> see if >> > > we >> > > > can somehow scope mvcc to row or at least shard mvcc so not all >> Region >> > > ops >> > > > are paused. >> > > > >> > > > St.Ack >> > > > >> > > > >> > > > On Mon, Sep 14, 2015 at 4:15 AM, 鈴木俊裕 <brfrn...@gmail.com> wrote: >> > > > >> > > > > > Thank you for the below reasoning (with accompanying helpful >> > > diagram). >> > > > > > Makes sense. Let me hack up a test case to help with the >> > > illustration. >> > > > It >> > > > > > is as though the mvcc should be scoped to a row only... Writes >> > > against >> > > > > > other rows should not hold up my read of my row. Tag an mvcc >> with a >> > > > 'row' >> > > > > > scope so we can see which on-going writes pertain to current >> > > operation? >> > > > > Thank you St.Ack! I think this approach would work. >> > > > > >> > > > > > You need to read back the increment and have it be 'correct' at >> > > > increment >> > > > > > time? >> > > > > Yes, we need it. >> > > > > >> > > > > I would like to help if there is anything I can do. >> > > > > >> > > > > Thanks, >> > > > > Toshihiro Suzuki >> > > > > >> > > > > >> > > > > 2015-09-13 14:11 GMT+09:00 Stack <st...@duboce.net>: >> > > > > >> > > > > > Thank you for the below reasoning (with accompanying helpful >> > > diagram). >> > > > > > Makes sense. Let me hack up a test case to help with the >> > > illustration. >> > > > It >> > > > > > is as though the mvcc should be scoped to a row only... Writes >> > > against >> > > > > > other rows should not hold up my read of my row. Tag an mvcc >> with a >> > > > 'row' >> > > > > > scope so we can see which on-going writes pertain to current >> > > operation? >> > > > > > >> > > > > > You need to read back the increment and have it be 'correct' at >> > > > increment >> > > > > > time? >> > > > > > >> > > > > > (This is a good one) >> > > > > > >> > > > > > Thank you Toshihiro Suzuki >> > > > > > St.Ack >> > > > > > >> > > > > > On Sat, Sep 12, 2015 at 8:09 AM, 鈴木俊裕 <brfrn...@gmail.com> >> wrote: >> > > > > > >> > > > > > > St.Ack, >> > > > > > > >> > > > > > > Thank you for your response. >> > > > > > > >> > > > > > > Why I make out that "A region lock (not a row lock) seems to >> > occur >> > > in >> > > > > > > waitForPreviousTransactionsComplete()" is as follows: >> > > > > > > >> > > > > > > A increment operation has 3 procedures for MVCC. >> > > > > > > >> > > > > > > 1. mvcc.waitForPreviousTransactionsComplete(); >> > > > > > > >> > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> https://github.com/cloudera/hbase/blob/cdh5.4.5-release/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java#L6712 >> > > > > > > >> > > > > > > 2. w = mvcc.beginMemstoreInsertWithSeqNum(mvccNum); >> > > > > > > >> > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> https://github.com/cloudera/hbase/blob/cdh5.4.5-release/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java#L6721 >> > > > > > > >> > > > > > > 3. mvcc.completeMemstoreInsertWithSeqNum(w, walKey); >> > > > > > > >> > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> https://github.com/cloudera/hbase/blob/cdh5.4.5-release/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java#L6893 >> > > > > > > >> > > > > > > >> > > > > > > I think that MultiVersionConsistencyControl's writeQueue can >> > cause >> > > a >> > > > > > region >> > > > > > > lock. >> > > > > > > >> > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> https://github.com/cloudera/hbase/blob/cdh5.4.5-release/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MultiVersionConsistencyControl.java#L42-L43 >> > > > > > > >> > > > > > > >> > > > > > > Step 2 adds to a WriteEntry to writeQueue. >> > > > > > > >> > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> https://github.com/cloudera/hbase/blob/cdh5.4.5-release/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MultiVersionConsistencyControl.java#L102-L108 >> > > > > > > >> > > > > > > Step 3 removes the WriteEntry from writeQueue. >> > > > > > > >> > > > > > > completeMemstoreInsertWithSeqNum(w, walKey) -> >> > > > > > > waitForPreviousTransactionsComplete(e) -> advanceMemstore(w) >> > > > > > > >> > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> https://github.com/cloudera/hbase/blob/cdh5.4.5-release/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MultiVersionConsistencyControl.java#L127 >> > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> https://github.com/cloudera/hbase/blob/cdh5.4.5-release/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MultiVersionConsistencyControl.java#L235 >> > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> https://github.com/cloudera/hbase/blob/cdh5.4.5-release/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MultiVersionConsistencyControl.java#L160 >> > > > > > > >> > > > > > > Step 1 adds a WriteEntry w in beginMemstoreInsert() to >> writeQueue >> > > and >> > > > > > waits >> > > > > > > until writeQueue is empty or writeQueue.getFirst() == w. >> > > > > > > >> > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> https://github.com/cloudera/hbase/blob/cdh5.4.5-release/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MultiVersionConsistencyControl.java#L201-L204 >> > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> https://github.com/cloudera/hbase/blob/cdh5.4.5-release/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MultiVersionConsistencyControl.java#L206-L241 >> > > > > > > >> > > > > > > >> > > > > > > I think when a handler thread is processing between step 2 and >> > step >> > > > 3, >> > > > > > the >> > > > > > > other handler threads can wait at step 1 until the thread >> > completes >> > > > > step >> > > > > > 3 >> > > > > > > This is depicted as follows: >> > > > > > > >> > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> https://gist.githubusercontent.com/brfrn169/cb4f2c157129330cd932/raw/86d6aae5667b0fe006b16fed80f1b0c4945c7fd0/region_lock.png >> > > > > > > >> > > > > > > >> > > > > > > Actually, in the thread dump of our region server, many >> handler >> > > > threads >> > > > > > > (RW.default.writeRpcServer.handler) wait at Step 1 >> > > > > > > (waitForPreviousTransactionsComplete()). >> > > > > > > >> > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> https://gist.githubusercontent.com/brfrn169/cb4f2c157129330cd932/raw/86d6aae5667b0fe006b16fed80f1b0c4945c7fd0/thread_dump.txt >> > > > > > > >> > > > > > > Many handler threads wait at this: >> > > > > > > >> > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> https://github.com/cloudera/hbase/blob/cdh5.4.5-release/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MultiVersionConsistencyControl.java#L224 >> > > > > > > >> > > > > > > >> > > > > > > > Is it possible you are contending on a counter post-upgrade? >> > Is >> > > it >> > > > > > > > possible that all these threads are trying to get to the >> same >> > row >> > > > to >> > > > > > > update >> > > > > > > > it? Could the app behavior have changed? Or are you >> thinking >> > > > > increment >> > > > > > > > itself has slowed significantly? >> > > > > > > We have just upgraded HBase, not changed the app behavior. We >> are >> > > > > > thinking >> > > > > > > increment itself has slowed significantly. >> > > > > > > Before upgrading HBase, it was good throughput and latency. >> > > > > > > Currently, to cope with this problem, we split the regions >> > finely. >> > > > > > > >> > > > > > > Thanks, >> > > > > > > >> > > > > > > Toshihiro Suzuki >> > > > > > > >> > > > > > > >> > > > > > > 2015-09-09 15:29 GMT+09:00 Stack <st...@duboce.net>: >> > > > > > > >> > > > > > > > On Tue, Sep 8, 2015 at 10:22 PM, 鈴木俊裕 <brfrn...@gmail.com> >> > > wrote: >> > > > > > > > >> > > > > > > > > Ted, >> > > > > > > > > >> > > > > > > > > Thank you for your response. >> > > > > > > > > >> > > > > > > > > I uploaded the complete stack trace to Gist. >> > > > > > > > > >> > > > > > > > > https://gist.github.com/brfrn169/cb4f2c157129330cd932 >> > > > > > > > > >> > > > > > > > > >> > > > > > > > > I think that increment operation works as follows: >> > > > > > > > > >> > > > > > > > > 1. get row lock >> > > > > > > > > 2. mvcc.waitForPreviousTransactionsComplete() // wait for >> all >> > > > prior >> > > > > > > MVCC >> > > > > > > > > transactions to finish >> > > > > > > > > 3. mvcc.beginMemstoreInsertWithSeqNum() // start a >> > transaction >> > > > > > > > > 4. get previous values >> > > > > > > > > 5. create KVs >> > > > > > > > > 6. write to Memstore >> > > > > > > > > 7. write to WAL >> > > > > > > > > 8. release row lock >> > > > > > > > > 9. mvcc.completeMemstoreInsertWithSeqNum() // complete the >> > > > > > transaction >> > > > > > > > > >> > > > > > > > > A instance of MultiVersionConsistencyControl has a pending >> > > queue >> > > > of >> > > > > > > > writes >> > > > > > > > > named writeQueue. >> > > > > > > > > Step 2 puts a WriteEntry w to writeQueue and waits until >> > > > writeQueue >> > > > > > is >> > > > > > > > > empty or writeQueue.getFirst() == w. >> > > > > > > > > Step 3 puts a WriteEntry to writeQueue and step 9 removes >> the >> > > > > > > WriteEntry >> > > > > > > > > from writeQueue. >> > > > > > > > > >> > > > > > > > > I think that when a handler thread is processing between >> > step 2 >> > > > and >> > > > > > > step >> > > > > > > > 9, >> > > > > > > > > the other handler threads can wait until the thread >> completes >> > > > step >> > > > > 9. >> > > > > > > > > >> > > > > > > > > >> > > > > > > > That is right. We need to read, after all outstanding >> updates >> > are >> > > > > > done... >> > > > > > > > because we need to read the latest update before we go to >> > > > > > > modify/increment >> > > > > > > > it. >> > > > > > > > >> > > > > > > > How do you make out this? >> > > > > > > > >> > > > > > > > "A region lock (not a row lock) seems to occur in >> > > > > > > > waitForPreviousTransactionsComplete()." >> > > > > > > > >> > > > > > > > In 0.98.x we did this: >> > > > > > > > >> > > > > > > > mvcc.completeMemstoreInsert(mvcc.beginMemstoreInsert()); >> > > > > > > > >> > > > > > > > ... and in 1.0 we do this: >> > > > > > > > >> > > > > > > > mvcc.waitForPreviousTransactionsComplete() which is this.... >> > > > > > > > >> > > > > > > > + public void waitForPreviousTransactionsComplete() { >> > > > > > > > + WriteEntry w = beginMemstoreInsert(); >> > > > > > > > + waitForPreviousTransactionsComplete(w); >> > > > > > > > + } >> > > > > > > > >> > > > > > > > The mvcc and region sequenceid were merged in 1.0 ( >> > > > > > > > https://issues.apache.org/jira/browse/HBASE-8763). Previous >> > mvcc >> > > > and >> > > > > > > > region >> > > > > > > > sequenceid would spin independent of each other. Perhaps >> this >> > > > > > responsible >> > > > > > > > for some slow down. >> > > > > > > > >> > > > > > > > That said, looking in your thread dump, we seem to be down >> in >> > the >> > > > > Get. >> > > > > > If >> > > > > > > > you do a bunch of thread dumps in a row, where is the >> > > lock-holding >> > > > > > > thread? >> > > > > > > > In Get or writing Increment... or waiting on sequence id? >> > > > > > > > >> > > > > > > > Is it possible you are contending on a counter post-upgrade? >> > Is >> > > it >> > > > > > > > possible that all these threads are trying to get to the >> same >> > row >> > > > to >> > > > > > > update >> > > > > > > > it? Could the app behavior have changed? Or are you >> thinking >> > > > > increment >> > > > > > > > itself has slowed significantly? >> > > > > > > > >> > > > > > > > St.Ack >> > > > > > > > >> > > > > > > > >> > > > > > > > >> > > > > > > > >> > > > > > > > > Thanks, >> > > > > > > > > >> > > > > > > > > Toshihiro Suzuki >> > > > > > > > > >> > > > > > > > > >> > > > > > > > > 2015-09-09 0:05 GMT+09:00 Ted Yu <yuzhih...@gmail.com>: >> > > > > > > > > >> > > > > > > > > > In HRegion#increment(), we lock the row (not region): >> > > > > > > > > > >> > > > > > > > > > try { >> > > > > > > > > > rowLock = getRowLock(row); >> > > > > > > > > > >> > > > > > > > > > Can you pastebin the complete stack trace ? >> > > > > > > > > > >> > > > > > > > > > Thanks >> > > > > > > > > > >> > > > > > > > > > On Tue, Sep 8, 2015 at 2:01 AM, 鈴木俊裕 < >> brfrn...@gmail.com> >> > > > wrote: >> > > > > > > > > > >> > > > > > > > > > > Hi, >> > > > > > > > > > > >> > > > > > > > > > > We upgraded our cluster from CDH5.3.1(HBase0.98.6) to >> > > > > > > > > > CDH5.4.5(HBase1.0.0) >> > > > > > > > > > > and we experience slowdown in increment operation. >> > > > > > > > > > > >> > > > > > > > > > > Here's an extract from thread dump of the >> RegionServer of >> > > our >> > > > > > > > cluster: >> > > > > > > > > > > >> > > > > > > > > > > Thread 68 >> > > > > > > (RW.default.writeRpcServer.handler=15,queue=5,port=60020): >> > > > > > > > > > > State: BLOCKED >> > > > > > > > > > > Blocked count: 21689888 >> > > > > > > > > > > Waited count: 39828360 >> > > > > > > > > > > Blocked on java.util.LinkedList@3474e4b2 >> > > > > > > > > > > Blocked by 63 >> > > > > > > > > (RW.default.writeRpcServer.handler=10,queue=0,port=60020) >> > > > > > > > > > > Stack: >> > > > > > > > > > > java.lang.Object.wait(Native Method) >> > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> org.apache.hadoop.hbase.regionserver.MultiVersionConsistencyControl.waitForPreviousTransactionsComplete(MultiVersionConsistencyControl.java:224) >> > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> org.apache.hadoop.hbase.regionserver.MultiVersionConsistencyControl.waitForPreviousTransactionsComplete(MultiVersionConsistencyControl.java:203) >> > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > >> > > > > > > >> > > > > >> > > >> org.apache.hadoop.hbase.regionserver.HRegion.increment(HRegion.java:6712) >> > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> org.apache.hadoop.hbase.regionserver.RSRpcServices.increment(RSRpcServices.java:501) >> > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> org.apache.hadoop.hbase.regionserver.RSRpcServices.doNonAtomicRegionMutation(RSRpcServices.java:570) >> > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> org.apache.hadoop.hbase.regionserver.RSRpcServices.multi(RSRpcServices.java:1901) >> > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> org.apache.hadoop.hbase.protobuf.generated.ClientProtos$ClientService$2.callBlockingMethod(ClientProtos.java:31451) >> > > > > > > > > > > >> > > > > > org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:2035) >> > > > > > > > > > > >> > > > > > org.apache.hadoop.hbase.ipc.CallRunner.run(CallRunner.java:107) >> > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> org.apache.hadoop.hbase.ipc.RpcExecutor.consumerLoop(RpcExecutor.java:130) >> > > > > > > > > > > >> > > > > > > > >> > > > org.apache.hadoop.hbase.ipc.RpcExecutor$1.run(RpcExecutor.java:107) >> > > > > > > > > > > java.lang.Thread.run(Thread.java:745) >> > > > > > > > > > > >> > > > > > > > > > > There are many similar threads in the thread dump. >> > > > > > > > > > > >> > > > > > > > > > > I read the source code and I think this is caused by >> > > changes >> > > > of >> > > > > > > > > > > MultiVersionConsistencyControl. >> > > > > > > > > > > A region lock (not a row lock) seems to occur in >> > > > > > > > > > > waitForPreviousTransactionsComplete(). >> > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > > Also we wrote performance test code for increment >> > operation >> > > > > that >> > > > > > > > > included >> > > > > > > > > > > 100 threads and ran it in local mode. >> > > > > > > > > > > >> > > > > > > > > > > The result is shown below: >> > > > > > > > > > > >> > > > > > > > > > > CDH5.3.1(HBase0.98.6) >> > > > > > > > > > > Throughput(op/s): 12757, Latency(ms): >> 7.975072509210629 >> > > > > > > > > > > >> > > > > > > > > > > CDH5.4.5(HBase1.0.0) >> > > > > > > > > > > Throughput(op/s): 2027, Latency(ms): 49.11840157868772 >> > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > > Thanks, >> > > > > > > > > > > >> > > > > > > > > > > Toshihiro Suzuki >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> >
