Hi, My read_repair_chance is 0 (AND read_repair_chance = 0.0)
When I bootstrap a new node there is around 700 sstables, but after auto compaction the number drop to around 100. I'm using C* 3.11.1. To solve the problem I've already changed to 'unchecked_tombstone_compaction': 'true'. Now should I run nodetool compact? And for the future crontab nodetool disableautocompaction? Thanks On 16-01-2018 11:35, Alexander Dejanovski wrote: > > Hi, > > The overlaps you're seeing on time windows aren't due to automatic > compactions, but to read repairs. > You must be reading at quorum or local_quorum which can perform > foreground read repair in case of digest mismatch. > > You can set unchecked_tombstone_compaction to true if you want to > perform single sstable compaction to purge tombstones and a patch has > recently been merged in to allow twcs to delete fully expired data > even in case of overlap between time windows (I can't remember if it's > been merged in 3.11.1). > Just so you know, the timestamp considered for time windows is the max > timestamp. You can have old data in recent time windows, but not the > opposite. > > Cheers, > > > Le mar. 16 janv. 2018 à 12:07, Cogumelos Maravilha > <cogumelosmaravi...@sapo.pt <mailto:cogumelosmaravi...@sapo.pt>> a écrit : > > Hi list, > > My settings: > > AND compaction = {'class': > 'org.apache.cassandra.db.compaction.TimeWindowCompactionStrategy', > 'compaction_window_size': '4', 'compaction_window_unit': 'HOURS', > 'enabled': 'true', 'max_threshold': '64', 'min_threshold': '2', > 'tombstone_compaction_interval': '15000', 'tombstone_threshold': > '0.2', > 'unchecked_tombstone_compaction': 'false'} > AND compression = {'chunk_length_in_kb': '64', 'class': > 'org.apache.cassandra.io > <http://org.apache.cassandra.io>.compress.LZ4Compressor'} > AND crc_check_chance = 0.0 > AND dclocal_read_repair_chance = 0.0 > AND default_time_to_live = 1555200 > AND gc_grace_seconds = 10800 > 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'; > > Running this script: > > for f in *Data.db; do > ls -lrt $f > output=$(sstablemetadata $f 2>/dev/null) > max=$(echo "$output" | grep Maximum\ timestamp | cut -d" " -f3 > | cut > -c 1-10) > min=$(echo "$output" | grep Minimum\ timestamp | cut -d" " -f3 > | cut > -c 1-10) > date -d @$max +'%d/%m/%Y %H:%M:%S' > date -d @$min +'%d/%m/%Y %H:%M:%S' > done > > on sstables I'm getting values like these: > > -rw-r--r-- 1 cassandra cassandra 12137573577 Jan 14 20:08 > mc-22750-big-Data.db > 14/01/2018 19:57:41 > 31/12/2017 19:06:48 > > -rw-r--r-- 1 cassandra cassandra 4669422106 Jan 14 06:55 > mc-22322-big-Data.db > 12/01/2018 07:59:57 > 28/12/2017 19:08:42 > > My goal is using TWCS for sstables expired fast because lots of > new data > is coming in. What is the best approach to archive that? Should I > disable auto compaction? > Thanks in advance. > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: user-unsubscr...@cassandra.apache.org > <mailto:user-unsubscr...@cassandra.apache.org> > For additional commands, e-mail: user-h...@cassandra.apache.org > <mailto:user-h...@cassandra.apache.org> > > -- > ----------------- > Alexander Dejanovski > France > @alexanderdeja > > Consultant > Apache Cassandra Consulting > http://www.thelastpickle.com <http://www.thelastpickle.com/>
