Hi, when index size gets bigger than the available RAM, then it depends on the configuration of your operating system what will happen exactly: - when there is swap space configured and swap space is available, the OS will assign disk-based memory for the index data, which will slow down index operations from in-memory speed to on-disk speed - if there is no swap space available, then either operations in ArangoDB will fail with an out-of-memory error, or worse, the operating system may trigger its OOM killer to terminate the process with the highest RAM usage, which will likely be arangod.
Note that all of the above applies for ArangoDB 3.1 and earlier. From ArangoDB version 3.2 on, we do offer an alternative storage engine based on RocksDB. This storage engine is designed to handle data bigger than the available RAM. With the RocksDB-based storage engine, index data that is not in RAM will be loaded from disk when it is not in the in-memory hot set. So operations that need to load data from disk will be slower than operations that can access data already in RAM. The engine will automatically keep the hot set in memory, so if you're only accessing a hot set of data that fits into the available RAM, it should be fine. If you will be accessing your entire data set and it is much bigger than RAM, then all operations will slow down. But there is no way to avoid this, even with other databases, which will behave similarly. ArangoDB 3.2 is currently in the end of its alpha stage, and will very soon go into beta stage. I recommend to give it a test drive and try the new storage engine that is shipped with it. Best regards Jan Am Sonntag, 11. Juni 2017 17:37:28 UTC+2 schrieb gelin yan: > > Hi All > > I am interested in arangodb in terms of its features. My question is if > the db index size is larger than RAM, What will happen? Will arangodb crash > immediately or run slowly? > > Regards > > gelin yan > -- You received this message because you are subscribed to the Google Groups "ArangoDB" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
