What are the implications of using low GCGraceSeconds in Cassandra?

Question

The default value for Cassandra for GCGraceSeconds is 10 days.

I wonder why this is defaulted, what is big and what will be the consequences if it is a smaller number, for example, 60 seconds.

The reason for the request is that I want to achieve faster “cleaning” of the ghost lines that appear after they are deleted. I often read these lines with some scans and need to put some logic in the client to verify that the content has not yet been deleted.

How can the lower value of GCGraceSeconds affect the system and how does it compare with the presence of this kind of ghost strings over several days?

Answer 1

GCGraceSeconds sets an upper bound on the time during which the cluster was to distribute gravestones. A low second GC gradation means that if the host does not connect to this period and does not receive a tombstone, then the deleted value may "return from the dead."

It is recommended that you start repairs at least every GCGraceSeconds so that you can ensure that the headstone has been replicated. With a very small value for this, you will not be able to carry out repairs often enough.