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F1: A Distributed SQL Database That Scales
- dvliman 13y agoThis is not new by any mean...
- jahewson 13y agoThe paper was only published in conference proceedings yesterday.
- paulsamways 13y agoSee http://research.google.com/pubs/pub38125.html http://research.google.com/pubs/pub38125.html
- packetslave 13y ago"not new" != "not interesting"
- jacques_chester 13y agoImpressive, as one might expect. Some reactions: -- Secret sauce A lot of the magic of F1 comes from Spanner, the distributed storage system. The name "F1" itself is an allusion to "inheriting" some of the properties of Spanner. -- Hierarchical tables What they call hierarchical tables, I would think best be viewed as one-to-many relationships. In guess they've privileged this model in their storage because that's what a lot of their AdWords schema looks like. -- Change History I like the observation that keeping full histories is relatively straightforward with atomic, granular timestamping and indeed that it should be baked in. Every database schema I've ever worked with always goes through a similar evolutionary cycle: 1. We only need to capture the current state of the model. 2. Wait, we do need to capture historical states of the model. 3. Wait, the model is changed, we need to capture historical states and the models that were current. (You can think of this as taking progressive differentials of incoming transactions). The F1 designers have baked that right into the database, where it belongs. Weak temporal support has long been the sore point in SQL. -- Remote data I was struck by their observation that most database storage engines are built around the concept of seeks and reads, whereas theirs is necessarily built around batching and pipelining over a network. If I am reading them correctly, their engine takes advantage of having multiple copies of data by sending reads to multiple disk nodes and then working from the first copy that is returned.
- vosper 13y agoYour point about change history and its poor support in SQL is spot-on; at my employer we've gone through (1) and (2) and are trying to figure out (3) at the moment. From what I understand of Datomic temporal support is baked in, but it's about the only database I can think of that does that, and I haven't heard stories about it being used in production for large volumes of data.
- jacques_chester 13y agoSnodgrass wrote an entire book about dealing with the temporal blindness of SQL which might help you: http://www.cs.arizona.edu/people/rts/tdbbook.pdf http://www.cs.arizona.edu/people/rts/tdbbook.pdf More generally, you can usually build a model that handles (2), the changing state, by generalising your original model. I've done in both of classical ways, having either validity period fields (thus pushing complexity into every query), or by having audit tables (thus relying on triggers). But building a changing model is hard, because at the schema level, SQL only supports (1). That is, it provides primitives to change the current state of the model. So you wind up having to build a meta-model. The deficiencies of SQL (and I'm an RDBMS bigot) mean that we wind up building inner platforms. Or outer platforms -- witness migration toolkits. Yet support for changing models is essential. No model is ever constant. Most of my work is for a public-sector client whose legal reporting requirements are constantly changing. You cannot throw away old reports which were made under old regulations; you must be able to recreate the world at any point in time. Which requires either a lot of bookkeeping code or taking periodic snapshots. Datomic looks neat. I see that I'm not the only one who made the leap from transactional memory to transactional models. Edit: I just found notes I wrote in 2009 on database languages while looking for something else. Spooky: http://chester.id.au/2013/08/28/notes-towards-a-set-objective-language/ http://chester.id.au/2013/08/28/notes-towards-a-set-objectiv...
- twic 13y agoDatabases which use MVCC handle (2) - and if they have transactional DDL, then they cover (3). But they don't keep the history permanently. Who wants all that old data? The one exception to this that i know of is Oracle, which although not fashionable round here, does expose the MVCC log through "flashback queries", where one can simply write "SELECT * FROM USER AS OF TIMESTAMP (SYSTIMESTAMP - INTERVAL '60' MINUTE)": http://docs.oracle.com/cd/B28359_01/appdev.111/b28424/adfns_flashback.htm http://docs.oracle.com/cd/B28359_01/appdev.111/b28424/adfns_... I don't know what the logistics of keeping an infinite history are. I do know that an e-commerce system i worked with before kept a few days, and that that saved our bacon on a couple of occasions.
- fintler 13y agoI posted this question on StackOverflow regarding TrueTime (used by Spanner) a few days ago and haven't received any responses: <http://stackoverflow.com/questions/18384883/why-is-googles-truetime-api-hard-to-duplicate> http://stackoverflow.com/questions/18384883/why-is-googles-t... However, I think this HN thread seems like it might be a good place to get comments on why my line of reasoning may be incorrect. Does anyone have any thoughts on why building something like Spanner on top of basic Paxos quorums and NTP would be a bad idea?
- capkutay 13y agoCan someone enlighten me as to why google doesn't want to make an enterprise play? Many companies tout that they are offering data infrastructures similar to those used at google..why wouldn't google commercialize that technology themselves? It should be pretty obvious as to how that could be of huge financial benefit to the company.
- dragonwriter 13y ago> Can someone enlighten me as to why google doesn't want to make an enterprise play? They do. They have a range of commercial, including enterprise, offerings (many of which are based on originally-internal technologies, including their MySQL-based distributed database that preceded F1.) > why wouldn't google commercialize that technology themselves? They probably will, just as they have commercialized their previous internal storage technologies.