| = zombie |
| |
| A row or cell that reappears in a database table after deletion. |
| This can happen if a node goes down for a long period of time and is then restored without being repaired. |
| |
| Deleted data is not erased from database tables; it is marked with <<tombstone,tombstones>> until compaction. |
| The tombstones created on one node must be propagated to the nodes containing the deleted data. |
| If one of these nodes goes down before this happens, the node may not receive the most up-to-date tombstones. |
| If the node is not repaired before it comes back online, the database finds the non-tombstoned items and propagates them to other nodes as new data. |
| |
| To avoid this problem, run nodetool repair on any restored node before rejoining it to its cluster. |
