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From learner dba <cassandra...@yahoo.com.INVALID>
Subject Re: Timeout for only one keyspace in cluster
Date Mon, 23 Jul 2018 17:36:54 GMT
 Thanks Jonathan.
this is device addition use case where we can't assign same value to more than one device,
so we need isolation property. With regular UUID, we may end up assigning same value to two
devices. I will talk to dev team and see if this can be changed and handled at application
level.
    On Monday, July 23, 2018, 12:01:15 PM CDT, Jonathan Haddad <jon@jonhaddad.com> wrote:
 
 
 You don’t get this guarantee with counters.  Do not use them for unique values. Use a
UUID instead. 
On Mon, Jul 23, 2018 at 9:11 AM learner dba <cassandradba@yahoo.com.invalid> wrote:

 James,
Yes, counter is implemented due to valid reasons. We need this value column to  have unique
values being used at the time of registering new devices.    On Monday, July 23, 2018, 10:07:54
AM CDT, James Shaw <jxyshaw@gmail.com> wrote:  
 
 does your application really need counter ?  just an option.
Thanks,
JamesOn Mon, Jul 23, 2018 at 10:57 AM, learner dba <cassandradba@yahoo.com. invalid>
wrote:

 Thanks a lot Ben. This makes sense but feel bad that we don't have a solution yet. We can
try consistency level one but that will be against general rule for having local_quorum for
production. Also, consistency ONE will not guarantee 0 race condition.
Is there any better solution?
 

  On Saturday, July 21, 2018, 8:27:57 PM CDT, Ben Slater <ben.slater@instaclustr.com>
wrote:  
 
 

Note that that writetimeout exception can be C*s way of telling you when there is contention
on a LWT (rather than actually timing out). See https://issues.apache.org/ jira/browse/CASSANDRA-9328
CheersBen


On Sun, 22 Jul 2018 at 11:20 Goutham reddy <goutham.chirutha@gmail.com> wrote:



Hi,As it is a single partition key, try to update the key with only partition key instead
of passing other columns. And try to set consistency level ONE. 
Cheers,Goutham.



On Fri, Jul 20, 2018 at 6:57 AM learner dba <cassandradba@yahoo.com.invali d> wrote:





 Anybody has any ideas about this? This is happening in production and we really need to fix
it.
 





  On Thursday, July 19, 2018, 10:41:59 AM CDT, learner dba <cassandradba@yahoo.com.INVALI
D> wrote:  
 
 





 Our foreignid is unique idetifier and we did check for wide partitions; cfhistorgrams show
all partitions are evenly sized:

Percentile  SSTables     Write Latency      Read Latency    Partition Size     
  Cell Count

                              (micros)          (micros)          
(bytes)                  

50%             0.00             29.52              0.00         
    1916                12

75%             0.00             42.51              0.00         
    2299                12

95%             0.00             61.21              0.00         
    2759                14

98%             0.00             73.46              0.00         
    2759                17

99%             0.00             88.15              0.00         
    2759                17

Min             0.00              9.89              0.00          
    150                 2

Max             0.00             88.15              0.00          
7007506             42510
any thing else that we can check?
 





  On Wednesday, July 18, 2018, 10:44:29 PM CDT, wxn002@zjqunshuo.com <wxn002@zjqunshuo.com>
wrote:  
 
 





Your partition key is foreignid. You may have a large partition. Why not use foreignid+timebucket
as partition key?







From: learner dbaDate: 2018-07-19 01:48To: User cassandra.apache.orgSubject: Timeout
for only one keyspace in cluster







Hi,
We have a cluster with multiple keyspaces. All queries are performing good but write operation
on few tables in one specific keyspace gets write timeout. Table has counter column and counter
update query times out always. Any idea?









CREATE TABLE x.y (

    foreignid uuid,

    timebucket text,

    key text,

    timevalue int,

    value counter,

    PRIMARY KEY (foreignid, timebucket, key, timevalue)

) WITH CLUSTERING ORDER BY (timebucket ASC, key ASC, timevalue ASC)

    AND bloom_filter_fp_chance = 0.01

    AND caching = {'keys': 'ALL', 'rows_per_partition': 'NONE'}

    AND comment = ''









    AND compaction = {'class': 'org.apache.cassandra.db.compa ction.SizeTieredCompactionStra
tegy', 'max_threshold': '32', 'min_threshold': '4'}









    AND compression = {'chunk_length_in_kb': '64', 'class': 'org.apache.cassandra.io.compr
ess.LZ4Compressor'}

    AND crc_check_chance = 1.0

    AND dclocal_read_repair_chance = 0.1

    AND default_time_to_live = 0

    AND gc_grace_seconds = 864000

    AND max_index_interval = 2048

    AND memtable_flush_period_in_ms = 0

    AND min_index_interval = 128

    AND read_repair_chance = 0.0

    AND speculative_retry = '99PERCENTILE';









Query and Error:
UPDATE x.y SET value = value + 1 where foreignid = ? AND timebucket = ? AND key = ? AND timevalue
= ?, err = &errors.errorString{s:\"gocql: no response received from cassandra within timeout
period
I verified CL=local_serialWe had been working on this issue for many days; any help will be
much appreciated.







-- 
Regards
Goutham Reddy



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