The best data model always depends on the structure of data and the
access pattern. The natural access pattern for your messages is likely
lookup from two sides: sender and receiver. And you might need to
support message expiry too. This means that you need on-disk indeces if
you want more messages than will fit in memory.
In Riak you can do it quite simply with any of the ordered backends
(leveldb, hanoidb, lowkeydb):
One message = one Riak object. Example: {sender='321', recipient='123',
timestamp = 1234567, text= 'bla bla'}
Key is timestamp prefixed.
2i indeces for <sender_id> and <recipient_id>.
Consider using a compound index if you often distinguish between
read/unread messages. For instance: <read-status>_<recipient_id>
Example query returning keys for all unread messages belonging to
recipient with id 123 using compound index:
http://myhost:8098/buckets/messages/index/recipient_bin/unread_123
Example query returning keys for all messages older than a year, so you
can delete old messages (not necesary using backends with autoexpiry):
http://myhost:8098/buckets/messages/index/$key/0/2011-09-21
Here is an alternative approach: You can choose to optimize for the
recipient side of the access pattern, by bulking all the messages for a
given recipient in one Riak object. This is much faster that retrieving
a large number of messages individually, the price being more difficult
lookup from the sender side:
Key: recipient_id
One Riak Object = all messages for a given recipient. Example:
[{sender='321', timestamp = 1234567, text= 'bla bla'},{sender='456',
timestamp = 1234569, text= 'bla bla2'}]
2i index for <sender_id>s
Example query returning an object with all messages belonging to
recipient with id 123:
http://myhost:8098/buckets/messages/keys/123
If you want text search on for instance message content, you should
consider using Riak Search.
- Rune
Trifork
Best regards / Venlig hilsen
*Rune Skou Larsen*
Trifork Public A/S / Team Riak
Margrethepladsen 4, 8000 Århus C, Denmark
Phone: +45 3160 2497 Skype: runeskoularsen twitter: @RuneSkouLarsen
On 20-09-2012 01:33, Charlie Bowman wrote:
I'm in the process of designing an in game messaging system that
basically replicates the same functionality of email all within the
context of the application. I do not have a ton of experience with
true key/value db stores so I'm looking to find a good resource for
ideas on how to best model this. I have a first version, but I dont
want to reinvent the wheel if can help it. I've done the requisite
googling, but haven't found anything relevant yet. Are there any
guides/tutorials/open source projects that anyone knows of.
Thanks!
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