RocksDBException thrown for .ldb file not found when calling ingestExternalFile()

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### Expected behavior

`ingestExternalFile()` should be able to successfully ingest SST files.

### Actual behavior

RocksDBException is thrown indicating that a `.ldb` file could not be found.

The error message is:

> While open a file for random read: //002462.ldb: No such file or directory

### Steps to reproduce the behavior

Unknown what exact conditions are causing this behavior. The database contains about 28 million keys. Storage utilization is not an issue.

We periodically (about every 30 minutes) refresh data and publish the availability of new SST files to be ingested. At that time we attempt to ingest the new SST file(s).

We are using version `7.2.2`.