Hallo,
we work with Cassandra version 3.0.9 and have a problem in a table with TWCS.
The command "nodetool repair" create always new files with old data. This avoid
the delete of the old data.
The layout of the Table is following:
cqlsh> desc stat.spa
CREATE TABLE stat.spa (
region int,
id int,
date text,
hour int,
zippedjsonstring blob,
PRIMARY KEY ((region, id), date, hour)
) WITH CLUSTERING ORDER BY (date ASC, hour 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.compaction.TimeWindowCompactionStrategy',
'compaction_window_size': '1', 'compaction_window_unit': 'DAYS',
'max_threshold': '100', 'min_threshold': '4', 'tombstone_compaction_interval':
'86460'}
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 = 0.0
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';
Actual the oldest data are from 2017/04/15 and will not remove:
$ for f in *Data.db; do meta=$(sudo sstablemetadata $f); echo -e "Max:" $(date
--date=@$(echo "$meta" | grep Maximum\ time | cut -d" " -f3| cut -c 1-10)
'+%Y/%m/%d %H:%M') "Min:" $(date --date=@$(echo "$meta" | grep Minimum\ time |
cut -d" " -f3| cut -c 1-10) '+%Y/%m/%d %H:%M') $(echo "$meta" | grep
droppable) $(echo "$meta" | grep "Repaired at") ' \t ' $(ls -lh $f | awk
'{print $5" "$6" "$7" "$8" "$9}'); done | sort
Max: 2017/04/15 12:08 Min: 2017/03/31 13:09 Estimated droppable tombstones:
1.7731048805815162 Repaired at: 1525685601400 42K May 7 19:56
mc-22922-big-Data.db
Max: 2017/04/17 13:49 Min: 2017/03/31 13:09 Estimated droppable tombstones:
1.9600207684319835 Repaired at: 1525685601400 116M May 7 13:31
mc-15096-big-Data.db
Max: 2017/04/21 13:43 Min: 2017/04/15 13:34 Estimated droppable tombstones:
1.9090909090909092 Repaired at: 1525685601400 11K May 7 19:56
mc-22921-big-Data.db
Max: 2017/05/23 21:45 Min: 2017/04/21 14:00 Estimated droppable tombstones:
1.8360655737704918 Repaired at: 1525685601400 21M May 7 19:56
mc-22919-big-Data.db
Max: 2017/06/12 15:19 Min: 2017/04/25 14:45 Estimated droppable tombstones:
1.8091397849462365 Repaired at: 1525685601400 19M May 7 14:36
mc-17095-big-Data.db
Max: 2017/06/15 15:26 Min: 2017/05/10 14:37 Estimated droppable tombstones:
1.76536312849162 Repaired at: 1529612605539 9.3M Jun 21 22:31
mc-25372-big-Data.db
...
After a "nodetool repair" run, a new big data file is created that include old
data from 2017/07/31.
Max: 2018/07/27 18:10 Min: 2017/03/31 13:13 Estimated droppable tombstones:
0.08392555471691247 Repaired at: 0 11G Sep 11 22:02
mc-39281-big-Data.db
...
Max: 2018/08/16 18:18 Min: 2018/08/06 12:19 Estimated droppable tombstones: 0.0
Repaired at: 1534525730510 123M Aug 17 23:46 mc-36847-big-Data.db
Max: 2018/08/17 19:20 Min: 2017/07/31 12:04 Estimated droppable tombstones:
0.03385963490004347 Repaired at: 0 11G Sep 11 21:43
mc-39265-big-Data.db
Max: 2018/08/17 19:20 Min: 2018/07/24 12:33 Estimated droppable tombstones: 0.0
Repaired at: 1534525730510 135M Sep 11 21:44 mc-39270-big-Data.db
...
Max: 2018/09/06 17:30 Min: 2018/08/28 12:17 Estimated droppable tombstones: 0.0
Repaired at: 1536690786879 129M Sep 11 21:10 mc-39238-big-Data.db
Max: 2018/09/07 18:22 Min: 2017/04/23 12:48 Estimated droppable tombstones:
0.1548442441468401 Repaired at: 0 8.0G Sep 11 21:33 mc-39258-big-Data.db
Max: 2018/09/07 18:22 Min: 2018/09/07 12:15 Estimated droppable tombstones: 0.0
Repaired at: 1536690786879 72M Sep 11 21:34 mc-39262-big-Data.db
Max: 2018/09/08 18:20 Min: 2018/08/22 12:17 Estimated droppable tombstones: 0.0
Repaired at: 0 2.8G Sep 11 21:47 mc-39272-big-Data.db
The tool sstableexpiredblockers shows that the file mc-39281-big-Data.db blocks
95 expired files from getting dropped, for example the oldest file
mc-22922-big-Data.db
[BigTableReader(path='.../stat/spa-.../mc-39281-big-Data.db') (minTS =
1490958782530000, maxTS = 1532707837676719, maxLDT = 1557154990)
blocks 95 expired sstables from getting dropped:
[BigTableReader(path='.../stat/spa-.../mc-36936-big-Data.db') (minTS =
1500027128958000, maxTS = 1503666765807229, maxLDT = 1535202765)
[BigTableReader(path='.../stat/spa-.../mc-22921-big-Data.db') (minTS =
1492256093314000, maxTS = 1492775013454001, maxLDT = 1524311013)
[BigTableReader(path='.../stat/spa-.../mc-36947-big-Data.db') (minTS =
1492255708403000, maxTS = 1501937182477001, maxLDT = 1533473182)
[BigTableReader(path='.../stat/spa-.../mc-32582-big-Data.db') (minTS =
1493028031639000, maxTS = 1499175057476001, maxLDT = 1530711057)
[BigTableReader(path='.../stat/spa-.../mc-32560-big-Data.db') (minTS =
1500210297826000, maxTS = 1501416691390001, maxLDT = 1532952691)
[BigTableReader(path='.../stat/spa-.../mc-32528-big-Data.db') (minTS =
1490958761762000, maxTS = 1504358072394248, maxLDT = 1535894072)
[BigTableReader(path='.../stat/spa-.../mc-32572-big-Data.db') (minTS =
1500027103795000, maxTS = 1500297137808001, maxLDT = 1531833137)
[BigTableReader(path='.../stat/spa-.../mc-36935-big-Data.db') (minTS =
1500038582669000, maxTS = 1503839159485824, maxLDT = 1535375159)
[BigTableReader(path='.../stat/spa-.../mc-22922-big-Data.db') (minTS =
1490958570018000, maxTS = 1492250905633001, maxLDT = 1523786905)
[BigTableReader(path='.../stat/spa-.../mc-33470-big-Data.db') (minTS =
1499940836241000, maxTS = 1500040376685000, maxLDT = 1531576376)
Why create the repair such turbulence in new data files and how can we remove
the old data?
Kind Regards
Maik Cäsar
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