If all of your data is TTL’d and you never explicitly delete a cell without using s TTL, you can probably drop your GCGS to 1 hour (or less).
Which compaction strategy are you using? You need a way to clear out those tombstones. There exist tombstone compaction sub properties that can help encourage compaction to grab sstables just because they’re full of tombstones which will probably help you. -- Jeff Jirsa > On Feb 22, 2019, at 8:37 AM, Kenneth Brotman <kenbrot...@yahoo.com.invalid> > wrote: > > Can we see the histogram? Why wouldn’t you at times have that many > tombstones? Makes sense. > > Kenneth Brotman > > From: Rahul Reddy [mailto:rahulreddy1...@gmail.com] > Sent: Thursday, February 21, 2019 7:06 AM > To: user@cassandra.apache.org > Subject: Tombstones in memtable > > We have small table records are about 5k . > All the inserts comes as 4hr ttl and we have table level ttl 1 day and gc > grace seconds has 3 hours. We do 5k reads a second during peak load During > the peak load seeing Alerts for tomstone scanned histogram reaching million. > Cassandra version 3.11.1. Please let me know how can this tombstone scan can > be avoided in memtable
