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https://issues.apache.org/jira/browse/CASSANDRA-3465?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13146331#comment-13146331
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Alain RODRIGUEZ commented on CASSANDRA-3465:
--------------------------------------------
Sorry about the unclearness of my description, don't hesitate to ask me more
thing about this issue, I want to fix this asap, so I will help as much as I
can.
It's the same when trying with CL.ONE, CL.QUORUM or CL.ALL. I think the issue
doesn't come from the CL but from the RF, or more accurately from the way that
counters replicas are managed.
This test code : (3 nodes cluster, 1 CF described below, 5 rows with identical
column)
/*------------------------------ CODE ---------------------------------------*/
$servers = array("ec2-xxx-xxx-xxx-xxx.eu-west-1.compute.amazonaws.com",
"ec2-yyy-yyy-yyy-yyy.eu-west-1.compute.amazonaws.com",
"ec2-zzz-zzz-zzz-zzz.eu-west-1.compute.amazonaws.com");
$pool = new ConnectionPool("mykeyspace", $servers);
$stats_test = new ColumnFamily($pool, 'test_counter',
$read_consistency_level=cassandra_ConsistencyLevel::QUORUM,
$write_consistency_level=cassandra_ConsistencyLevel::QUORUM);
$time = date( 'YmdH', time());
for($i=0; $i<10; $i++){
for($c=1; $c<=5; $c++){
$stats_test->add($c, $time.':test');
}
$counts = $stats_test->multiget(array(1,2,3,4,5));
echo('Counter1: '.$counts[1][$time.':test']."\n");
echo('Counter2: '.$counts[2][$time.':test']."\n");
echo('Counter3: '.$counts[3][$time.':test']."\n");
echo('Counter4: '.$counts[4][$time.':test']."\n");
echo('Counter5: '.$counts[5][$time.':test']."\n\n");
}
/*-----------------------END OF CODE ---------------------------------------*/
Gives these outputs:
With RF = 1 :
Counter1: 1
Counter2: 1
Counter3: 1
Counter4: 1
Counter5: 1
Counter1: 2
Counter2: 2
Counter3: 2
Counter4: 2
Counter5: 2
Counter1: 3
Counter2: 3
Counter3: 3
Counter4: 3
Counter5: 3
Counter1: 4
Counter2: 4
Counter3: 4
Counter4: 4
Counter5: 4
Counter1: 5
Counter2: 5
Counter3: 5
Counter4: 5
Counter5: 5
Counter1: 6
Counter2: 6
Counter3: 6
Counter4: 6
Counter5: 6
Counter1: 7
Counter2: 7
Counter3: 7
Counter4: 7
Counter5: 7
Counter1: 8
Counter2: 8
Counter3: 8
Counter4: 8
Counter5: 8
Counter1: 9
Counter2: 9
Counter3: 9
Counter4: 9
Counter5: 9
Counter1: 10
Counter2: 10
Counter3: 10
Counter4: 10
Counter5: 10
This is the expected behaviour.
With RF = 2 :
Counter1: 1
Counter2: 1
Counter3: 1
Counter4: 1
Counter5: 1
Counter1: 2
Counter2: 2
Counter3: 2
Counter4: 2
Counter5: 1
Counter1: 3
Counter2: 3
Counter3: 3
Counter4: 3
Counter5: 1
Counter1: 4
Counter2: 4
Counter3: 3
Counter4: 4
Counter5: 2
Counter1: 5
Counter2: 5
Counter3: 3
Counter4: 5
Counter5: 3
Counter1: 6
Counter2: 6
Counter3: 3
Counter4: 6
Counter5: 4
Counter1: 7
Counter2: 7
Counter3: 3
Counter4: 7
Counter5: 5
Counter1: 8
Counter2: 8
Counter3: 4
Counter4: 8
Counter5: 5
Counter1: 9
Counter2: 9
Counter3: 4
Counter4: 9
Counter5: 6
Counter1: 10
Counter2: 10
Counter3: 4
Counter4: 10
Counter5: 6
And if I continue requesting for these counters I will always have 10 on
counters 1,2 and 4, but on counter 3 I will have either 4 or 6 alternatively
(it is the same with counter 5)
With RF = 3 :
Counter1: 1
Counter2: 1
Counter3: 1
Counter4: 1
Counter5: 1
Counter1: 2
Counter2: 1
Counter3: 2
Counter4: 2
Counter5: 2
Counter1: 2
Counter2: 2
Counter3: 3
Counter4: 2
Counter5: 3
Counter1: 2
Counter2: 3
Counter3: 4
Counter4: 3
Counter5: 4
Counter1: 3
Counter2: 3
Counter3: 5
Counter4: 3
Counter5: 4
Counter1: 4
Counter2: 3
Counter3: 6
Counter4: 3
Counter5: 5
Counter1: 5
Counter2: 3
Counter3: 7
Counter4: 4
Counter5: 5
Counter1: 6
Counter2: 4
Counter3: 6
Counter4: 5
Counter5: 6
Counter1: 7
Counter2: 5
Counter3: 7
Counter4: 5
Counter5: 7
Counter1: 7
Counter2: 6
Counter3: 8
Counter4: 6
Counter5: 7
Requesting for these rows more times gives me some differents values :
Counter1: 7
Counter2: 6
Counter3: 8
Counter4: 6
Counter5: 5
Counter1: 7
Counter2: 9
Counter3: 8
Counter4: 6
Counter5: 5
Here is the "show schema" of my keyspace :
create keyspace mykeyspace
with placement_strategy = 'SimpleStrategy'
and strategy_options = {replication_factor : 2} <-- I changed this value for
tests to 1, 2, 3
and durable_writes = true;
use mykeyspace;
create column family test_counter
with column_type = 'Standard'
and comparator = 'BytesType'
and default_validation_class = 'CounterColumnType'
and key_validation_class = 'BytesType'
and rows_cached = 0.0
and row_cache_save_period = 0
and row_cache_keys_to_save = 2147483647
and keys_cached = 200000.0
and key_cache_save_period = 14400
and read_repair_chance = 1.0
and gc_grace = 864000
and min_compaction_threshold = 4
and max_compaction_threshold = 32
and replicate_on_write = true
and row_cache_provider = 'ConcurrentLinkedHashCacheProvider'
and compaction_strategy =
'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy';
I think that my cluster is well configured :
Address DC Rack Status State Load Owns Token
x datacenter1 rack1 Up Normal 59.33 MB 33.33% 0
y datacenter1 rack1 Up Normal 64.45 MB 33.33%
56713727820156407428984779325531226112
z datacenter1 rack1 Up Normal 76.69 MB 33.33%
113427455640312814857969558651062452224
I hope the problem is better explained now. If some point is still unclear,
please let me know.
> Wrong counters values when RF > 1
> ---------------------------------
>
> Key: CASSANDRA-3465
> URL: https://issues.apache.org/jira/browse/CASSANDRA-3465
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Affects Versions: 1.0.0
> Environment: Amazon EC2 (cluster of 5 t1.micro), phpCassa 0.8.a.2
> Reporter: Alain RODRIGUEZ
> Assignee: Sylvain Lebresne
> Priority: Critical
>
> I have got a CF that contains many counters of some events. When I'm at RF =
> 1 and simulate 10 events, they are well counted.
> However, when I switch to a RF = 3, my counter show a wrong value that
> sometimes change when requested twice (it can return 7, then 5 instead of 10
> all the time).
> I first thought that it was a problem of CL because I seem to remember that I
> read once that I had to use CL.One for reads and writes with counters. So I
> tried with CL.One, without success...
> /*-------------------------------------------------- CODE
> -------------------------------------------------------*/
> $servers = array("ec2-xxx-xxx-xxx-xxx.eu-west-1.compute.amazonaws.com",
> "ec2-yyy-yyy-yyy-yyy.eu-west-1.compute.amazonaws.com",
> "ec2-zzz-zzz-zzz-zzz.eu-west-1.compute.amazonaws.com",
> "ec2-aaa-aaa-aaa-aaa.eu-west-1.compute.amazonaws.com",
> "ec2-bbb-bbb-bbb-bbb.eu-west-1.compute.amazonaws.com");
> $pool = new ConnectionPool("mykeyspace", $servers);
> $stats_test = new ColumnFamily($pool, 'stats_test',
> $read_consistency_level=cassandra_ConsistencyLevel::ONE,
> $write_consistency_level=cassandra_ConsistencyLevel::ONE);
>
> $time = date( 'YmdH', time());
>
> for($i=0; $i<10; $i++){
> for($c=1; $c<=3; $c++){
> $stats_test->add($c, $time.':test');
> }
> $counts = $stats_test->multiget(array(1,2,3));
> echo('Counter1: '.$counts[1][$time.':test']."\n");
> echo('Counter2: '.$counts[2][$time.':test']."\n");
> echo('Counter3: '.$counts[3][$time.':test']."\n\n");
> }
> /*-------------------------------- END OF CODE
> -------------------------------------------------------------------------*/
> /*-------------------------------------------------- OUTPUT
> ------------------------------------------------------------*/
> Counter1: 1
> Counter2: 1
> Counter3: 1
> Counter1: 2
> Counter2: 2
> Counter3: 2
> Counter1: 3
> Counter2: 3
> Counter3: 3
> Counter1: 3
> Counter2: 4
> Counter3: 4
> Counter1: 4
> Counter2: 5
> Counter3: 3
> Counter1: 5
> Counter2: 6
> Counter3: 3
> Counter1: 6
> Counter2: 7
> Counter3: 4
> Counter1: 4
> Counter2: 8
> Counter3: 7
> Counter1: 5
> Counter2: 9
> Counter3: 8
> Counter1: 8
> Counter2: 4
> Counter3: 9
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