[
https://issues.apache.org/jira/browse/CASSANDRA-12756?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15565868#comment-15565868
]
Alex Petrov commented on CASSANDRA-12756:
-----------------------------------------
In {{3.8}}: [CASSANDRA-12144].
> Duplicate (cql)rows for the same primary key
> --------------------------------------------
>
> Key: CASSANDRA-12756
> URL: https://issues.apache.org/jira/browse/CASSANDRA-12756
> Project: Cassandra
> Issue Type: Bug
> Components: Compaction, CQL
> Environment: Linux, Cassandra 3.7 (upgraded at one point from 2.?).
> Reporter: Andreas Wederbrand
> Priority: Minor
>
> I observe what looks like duplicates when I run cql queries against a table.
> It only show for rows written during a couple of hours on a specific date but
> it shows for several partions and serveral clustering keys for each partition
> during that time range.
> We've loaded data in two ways.
> 1) through a normal insert
> 2) through sstableloader with sstables created using update-statements (to
> append to the map) and an older version of SSTableWriter. During this
> processes several months of data was re-loaded.
> The table DDL is
> {code:title=create statement|borderStyle=solid}
> CREATE TABLE climate.climate_1510 (
> installation_id bigint,
> node_id bigint,
> time_bucket int,
> gateway_time timestamp,
> humidity map<int, float>,
> temperature map<int, float>,
> PRIMARY KEY ((installation_id, node_id, time_bucket), gateway_time)
> ) WITH CLUSTERING ORDER BY (gateway_time DESC)
> AND bloom_filter_fp_chance = 0.01
> AND caching = {'keys': 'ALL', 'rows_per_partition': 'NONE'}
> AND comment = ''
> AND compaction = {'class':
> 'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy',
> 'max_threshold': '32', 'min_threshold': '4'}
> AND compression = {'chunk_length_in_kb': '64', 'class':
> 'org.apache.cassandra.io.compress.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';
> {code}
> and the result from the SELECT is
> {code:title=cql output|borderStyle=solid}
> > select * from climate.climate_1510 where installation_id = 133235 and
> > node_id = 35453983 and time_bucket = 189 and gateway_time > '2016-08-10
> > 20:00:00' and gateway_time < '2016-08-10 21:00:00' ;
> installation_id | node_id | time_bucket | gateway_time |
> humidity | temperature
> -----------------+----------+-------------+--------------------------+----------+---------------
> 133235 | 35453983 | 189 | 20160810 20:23:28.000000 | {0:
> 51} | {0: 24.37891}
> 133235 | 35453983 | 189 | 20160810 20:23:28.000000 | {0:
> 51} | {0: 24.37891}
> 133235 | 35453983 | 189 | 20160810 20:23:28.000000 | {0:
> 51} | {0: 24.37891}
> {code}
> I've used Andrew Tolbert's sstable-tools to be able to dump the json for this
> specific time and this is what I find.
> {code:title=json dump|borderStyle=solid}
> [133235:35453983:189] Row[info=[ts=1470878906618000] ]:
> gateway_time=2016-08-10 22:23+0200 |
> del(humidity)=deletedAt=1470878906617999, localDeletion=1470878906,
> [humidity[0]=51.0 ts=1470878906618000],
> del(temperature)=deletedAt=1470878906617999, localDeletion=1470878906,
> [temperature[0]=24.378906 ts=1470878906618000]
> [133235:35453983:189] Row[info=[ts=-9223372036854775808]
> del=deletedAt=1470864506441999, localDeletion=1470864506 ]:
> gateway_time=2016-08-10 22:23+0200 | , [humidity[0]=51.0
> ts=1470878906618000], , [temperature[0]=24.378906 ts=1470878906618000]
> [133235:35453983:189] Row[info=[ts=-9223372036854775808]
> del=deletedAt=1470868106489000, localDeletion=1470868106 ]:
> gateway_time=2016-08-10 22:23+0200 |
> [133235:35453983:189] Row[info=[ts=-9223372036854775808]
> del=deletedAt=1470871706530999, localDeletion=1470871706 ]:
> gateway_time=2016-08-10 22:23+0200 |
> [133235:35453983:189] Row[info=[ts=-9223372036854775808]
> del=deletedAt=1470878906617999, localDeletion=1470878906 ]:
> gateway_time=2016-08-10 22:23+0200 | , [humidity[0]=51.0
> ts=1470878906618000], , [temperature[0]=24.378906 ts=1470878906618000]
> {code}
> From my understanding this should be impossible. Even if we have duplicates
> in the sstables (which is normal) it should be filtered away before being
> returned to the client.
> I'm happy to add details to this bug if anything is missing.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
