On 28 September 2016 at 17:59, Nguyen, Kyle <kyle.ngu...@philips.com> wrote:
> Thank you for your quick reply, Magnus! We’re considering using bucket > type to support multi-tenancy in our system. Hence, all objects stored > within the namespace of the bucket type and bucket type need to be removed > once the client has decided to opt-out. > > > > Thanks > > > > -Kyle- > > > Hi Kile, Riak uses bucket-types and buckets primarily as a name space. In a default configuration, the bucket type and bucket names are hashed together with the key, and this hash determines the location of a given object on the ring. This concept is known as consistent hashing and ensures that there are no hot spots and that data is evenly distributed across the partitions. Riak does *NOT* keep data stored under different bucket types or buckets separate from each other. Therefore, in order to delete all data stored under a given bucket type or bucket, it is necessary to delete each matching object individually. Furthermore, Riak does not keep an index of objects stored in a bucket type or bucket. It is possible to obtain lists of these objects via key-listing or mapreduce. However, these are very expensive operations in Riak and should be avoided in a high availability production cluster. You should also be aware of how deletion in Riak works. When an object is deleted, a tombstone is placed into the database (effectively an empty object with some additional metadata). Tombstones are eventually reaped during merging (bitcask) or compaction (leveldb) phases of the backend storage. However, there is no guarantee when this actually happens, and in particular with leveldb it can take a long time for any particular object to be actually deleted from disk. Please let me know if you have any additional questions regarding this topic. Kind Regards, Magnus -- Magnus Kessler Client Services Engineer Basho Technologies Limited Registered Office - 8 Lincoln’s Inn Fields London WC2A 3BP Reg 07970431
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