压缩是否应该在gc_grace_seconds内保留墓碑？

Question

如果我删除一行(创建一个墓碑),并在其中运行一个主要的压缩gc_grace_seconds,那么人们会期望墓碑至少存活至gc_grace_seconds已经过去吗？

Answer 1

Yes, the tombstone is expected to survive for gc_grace_seconds. The reason is that if a node is down at the point in time you delete the row, the delete must have a chance to get propagated to that node later on. When the node is back online and you run nodetool repair it can pick up the delete. If you do not run the repair within gc_grace_seconds then your deleted record might return from the dead.

IFF you are running a single-node cluster, then you can safely set gc_grace_seconds to 0. As there are no other nodes that might be missing deletes.

Have a look at this page on Cassandra operations, repair, and gc_grace_seconds.