CockroachDB, a distributed SQL database, encountered a significant performance issue during its testing phase, which involved a rapid decline in operations per second when writing random data into a table. This deterioration, observed by engineer Matt Tracy, was traced back to the inefficiency in handling deletion tombstones in RocksDB, the database's storage engine. The issue arose when the system attempted to iterate through a large number of deleted keys, which slowed down the process significantly. To address this, the team implemented a solution utilizing RocksDB's ability to set an upper-bound limit for iterator operations, effectively curtailing unnecessary iterations through deleted keys. This fix not only stabilized performance but also enhanced the database's overall top-end efficiency, leading to substantial improvements in various benchmarks.