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From "Dickson, Matt MR" <matt.dick...@defence.gov.au>
Subject RE: Failing to BulkIngest [SEC=UNOFFICIAL]
Date Sun, 23 Feb 2014 22:22:04 GMT
UNOFFICIAL

We have recently added functionality to merge old tablets, so these will be running while
bulk ingest is going.  The bulk ingest process checks for running compactions and will wait
until there are none, but does no co-ordination with running merges.  The bulk ingest and
merging are automated, bulk ingest runs hourly and the merge of old tablets runs daily.  Once
we get bulk ingest working again, should we pause ingest while the merge operations are run
to avoid/minimise FATE operations?

To help get the ingest working again, is there a way to list running merges?  Is it possible
to cancel a merge?

Matt
________________________________
From: Eric Newton [mailto:eric.newton@gmail.com]
Sent: Friday, 21 February 2014 15:49
To: user@accumulo.apache.org
Subject: Re: Failing to BulkIngest [SEC=UNOFFICIAL]

The locks are not a problem.

The problem is the creation of FATE transactions which require locks.

Why are you creating FATE operations?  Are you merging tablets?  Are you bulk importing while
other table-wide operations are in progress? Are these processes automated?

There is some bookkeeping in the !METADATA table, for FATE transactions, but not the other
way around.




On Thu, Feb 20, 2014 at 10:54 PM, Dickson, Matt MR <matt.dickson@defence.gov.au<mailto:matt.dickson@defence.gov.au>>
wrote:

UNOFFICIAL

Thanks for that.

We recreated the nodes and restarted Accumulo, but it went through and Added the locks back
during start up, so it appears Accumulo has knowledge of the locks, maybe in the metadata
table(?), and has updated the fate locks in zookeeper.  The issue of bulk ingest failing is
still occuring.

How can we investigate within Accumulo how it tracks these locks so that we can flush this
information also or identify the issue?

Matt
________________________________
From: Eric Newton [mailto:eric.newton@gmail.com<mailto:eric.newton@gmail.com>]
Sent: Friday, 21 February 2014 14:27

To: user@accumulo.apache.org<mailto:user@accumulo.apache.org>
Subject: Re: Failing to BulkIngest [SEC=UNOFFICIAL]

Sorry... I should have been more clear.

"-e" is for ephemeral, these are not ephemeral nodes. I think "-s" is the default, so you
don't need to specify it.

You can put anything in for the data.. it is unimportant:

cli>  create /accumulo/xx.../fate foo
cli>  create /accumulo/xx.../table_locks bar

I think that you can give the zkCli.sh shell quotes for an empty string:

cli> create /accumulo/xx.../fate ""

But, I can't remember if that works.  Accumulo never reads the contents of those nodes, so
anything you put in there will be ignored.

The master may even re-create these nodes on start-up, but I did not test it.

-Eric



On Thu, Feb 20, 2014 at 6:18 PM, Dickson, Matt MR <matt.dickson@defence.gov.au<mailto:matt.dickson@defence.gov.au>>
wrote:

UNOFFICIAL

After running the zkCli.sh rmr on the directories, we are having difficulties recreating the
nodes.

The zookeeper create command has 2 options -s and -e, but it's not clear what each of these
does and which one to use to recreate the accumulo node.  Also the create command requires
a 'data' name specified however when we look at our qa system the accumulo node has no data
name within it.

What is the zookeper command to run to recreate the /accumulo/xx.../fate and /accumulo/xx.../table_locks
nodes?

________________________________
From: Eric Newton [mailto:eric.newton@gmail.com<mailto:eric.newton@gmail.com>]
Sent: Friday, 21 February 2014 07:31

To: user@accumulo.apache.org<mailto:user@accumulo.apache.org>
Subject: Re: Failing to BulkIngest [SEC=UNOFFICIAL]

No, xxx... is your instance id.  You can find it at the top of the monitor page. It's the
ugly UUID there.

-Eric



On Thu, Feb 20, 2014 at 3:26 PM, Dickson, Matt MR <matt.dickson@defence.gov.au<mailto:matt.dickson@defence.gov.au>>
wrote:

UNOFFICIAL

Is the xxx... the transaction id returned by the 'fate.Admin print'?

Whats involved with recreating a node?

Matt

________________________________
From: Eric Newton [mailto:eric.newton@gmail.com<mailto:eric.newton@gmail.com>]
Sent: Friday, 21 February 2014 01:35

To: user@accumulo.apache.org<mailto:user@accumulo.apache.org>
Subject: Re: Failing to BulkIngest [SEC=UNOFFICIAL]

You can use the zkCli.sh utility to "rmr" /accumulo/xx.../fate and /accumulo/xx.../table_locks,
and then recreate those nodes.

-Eric



On Wed, Feb 19, 2014 at 5:58 PM, Dickson, Matt MR <matt.dickson@defence.gov.au<mailto:matt.dickson@defence.gov.au>>
wrote:

UNOFFICIAL

Thanks for your help on this Eric.

I've started deleting the transactions by running the, ./accumulo ...fate.Admin delete <txid>,
and notice this takes about 20 seconds per transaction.  With 7500 to delete this is going
to take a long time (almost 2 days), so I tried running several threads each with a seperate
range of id's to delete.  Unfortunately this seemed to have some contention and I kept recieving
an InvocationTargetException .... Caused by zookeeper.KeeperException: KeeperErrorCode = noNode
for /accumulo/xxxxx-xxxx-xxxx-xxxx/table_locks/3n/lock-xxxxxx

When I go back to one thread this error disappears.

Is there a better way to run this?

Thanks in advance,
Matt

________________________________
From: Eric Newton [mailto:eric.newton@gmail.com<mailto:eric.newton@gmail.com>]
Sent: Wednesday, 19 February 2014 01:21

To: user@accumulo.apache.org<mailto:user@accumulo.apache.org>
Subject: Re: Failing to BulkIngest [SEC=UNOFFICIAL]

The "LeaseExpiredException" is part of the recovery process.  The master determines that a
tablet server has lost its lock, or it is unresponsive and has been halted, possibly indirectly
by removing the lock.

The master then steals the write lease on the WAL file, which causes future writes to the
WALog to fail.  The message you have seen is part of that failure.  You should have seen a
tablet server failure associated with this message on the machine with <ip>.

Having 50K FATE IN_PROGRESS lines is bad.  That is preventing your bulk imports from getting
run.

Are there any lines that show locked: [W:3n] ?  The other FATE transactions are waiting to
get a READ lock on table id 3n.

-Eric



On Sun, Feb 16, 2014 at 7:59 PM, Dickson, Matt MR <matt.dickson@defence.gov.au<mailto:matt.dickson@defence.gov.au>>
wrote:
UNOFFICIAL

Josh,

Zookeepr - 3.4.5-cdh4.3.0
Accumulo - 1.5.0
Hadoop - cdh 4.3.0

In the accumulo console getting

ERROR RemoteException(...LeaseExpiredException): Lease mismatch on /accumulo/wal/<ip>+9997/<uid>
owned by DFSClient_NONMAPREDUCE_699577321_12 but is accessed by DFSClient_NONMAPREDUCE_903051502_12

We can scan the table without issues and can load rows directly, ie not using bulk import.

A bit more information - we recently extended how we manage old tablets in the system. We
load data by date, creating splits for each day and then ageoff using the ageoff filters.
 This leaves empty tablets so we now merge these old tablets together to effectively remove
them.  I mention it because I'm not sure if this might have introduced another issue.

Matt

-----Original Message-----
From: Josh Elser [mailto:josh.elser@gmail.com<mailto:josh.elser@gmail.com>]
Sent: Monday, 17 February 2014 11:32
To: user@accumulo.apache.org<mailto:user@accumulo.apache.org>
Subject: Re: Failing to BulkIngest [SEC=UNOFFICIAL]

Matt,

Can you provide Hadoop, ZK and Accumulo versions? Does the cluster appear to be functional
otherwise (can you scan that table you're bulk importing to? any other errors on the monitor?
etc)

On 2/16/14, 7:07 PM, Dickson, Matt MR wrote:
> *UNOFFICIAL*
>
> I have a situation where bulk ingests are failing with a "Thread "shell"
> stuck on IO to xxx:9999:99999 ...
>  From the management console the table we are loading to has no
> compactions running, yet we ran "./accumulo
> org.apache.accumulo.server.fate.Admin print and can see 50,000 lines
> stating
> txid: xxxx     status:IN_PROGRESS op: CompactRange     locked: []
> locking: [R:3n]     top: Compact:Range
> Does this mean there are actually compactions running or old
> comapaction locks still hanging around that will be preventing the builk ingest to run?
> Thanks in advance,
> Matt






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