Comment by lngnmn
9 years ago
> That's flat out wrong.
Oh, come on. Old time RDBMS have been designed to survive a sudden power outage - the system would rollback all the partially committed transactions to recover to the consistent state of the database.
The durability and data consistency is what defines a database in the first place.
For cache vs. database metaphor - think of the difference between a RAM-disk and HDD. This is fundamental difference. Protocol details are irrelevant.
This is why, say, sqlite is a database, while redis is not.
You are confusing the distinction between a cache & a non-durable datastore. Of course Redis is not a database, did I say it was?
Data is implicitly removed from a "cache" in course of normal operation.
Lets try it one last time.
In-memory database is as much a database as a RAM-disk is a disk.
Reducing technology assessment to puns is ultimately not very informative. I recommend you read up on Stonebraker's work the past few years. Durability issues of in-mem DBs are addressed.
It is certainly true that many pure mem vendors out there are playing fast and loose with terminology, but if one were to accept your assertions, then when the day arrives when spinning disks are antiques then I guess we no longer would have databases.