Michael Stonebraker
Discussion of the views of database management pioneer Mike Stonebraker. Related subjects include:
- Vertica
- StreamBase
- H-Store
- (in Software Memories) Stonebraker’s accomplishments
Soundbites: the Facebook/MySQL/NoSQL/VoltDB/Stonebraker flap, continued
As a follow-up to the latest Stonebraker kerfuffle, Derrick Harris asked me a bunch of smart followup questions. My responses and afterthoughts include:
- Facebook et al. are in effect Software as a Service (SaaS) vendors, not enterprise technology users. In particular:
- They have the technical chops to rewrite their code as needed.
- Unlike packaged software vendors, they’re not answerable to anybody for keeping legacy code alive after a rewrite. That makes migration a lot easier.
- If they want to write different parts of their system on different technical underpinnings, nobody can stop them. For example …
- … Facebook innovated Cassandra, and is now heavily committed to HBase.
- It makes little sense to talk of Facebook’s use of “MySQL.” Better to talk of Facebook’s use of “MySQL + memcached + non-transparent sharding.” That said:
- It’s hard to see why somebody today would use MySQL + memcached + non-transparent sharding for a new project. At least one of Couchbase or transparently-sharded MySQL is very likely a superior alternative. Other alternatives might be better yet.
- As noted above in the example of Facebook, the many major web businesses that are using MySQL + memcached + non-transparent sharding for existing projects can be presumed able to migrate away from that stack as the need arises.
Continuing with that discussion of DBMS alternatives:
- If you just want to write to the memcached API anyway, why not go with Couchbase?
- If you want to go relational, why not go with MySQL? There are many alternatives for scaling or accelerating MySQL — dbShards, Schooner, Akiban, Tokutek, ScaleBase, ScaleDB, Clustrix, and Xeround come to mind quickly, so there’s a great chance that one or more will fit your use case. (And if you don’t get the choice of MySQL flavor right the first time, porting to another one shouldn’t be all THAT awful.)
- If you really, really want to go in-memory, and don’t mind writing Java stored procedures, and don’t need to do the kinds of joins it isn’t good at, but do need to do the kinds of joins it is, VoltDB could indeed be a good alternative.
And while we’re at it — going schema-free often makes a whole lot of sense. I need to write much more about the point, but for now let’s just say that I look favorably on the Big Four schema-free/NoSQL options of MongoDB, Couchbase, HBase, and Cassandra.
An odd claim attributed to Mike Stonebraker
This post has a sequel.
Last week, Mike Stonebraker insulted MySQL and Facebook’s use of it, by implication advocating VoltDB instead. Kerfuffle ensued. To the extent Mike was saying that non-transparently sharded MySQL isn’t an ideal way to do things, he’s surely right. That still leaves a lot of options for massive short-request databases, however, including transparently sharded RDBMS, scale-out in-memory DBMS (whether or not VoltDB*), and various NoSQL options. If nothing else, Couchbase would seem superior to memcached/non-transparent MySQL if you were starting a project today.
*The big problem with VoltDB, last I checked, was its reliance on Java stored procedures to get work done.
Pleasantries continued in The Register, which got an amazing-sounding quote from Mike. If The Reg is to be believed — something I wouldn’t necessarily take for granted — Mike claimed that he (i.e. VoltDB) knows how to solve the distributed join performance problem. Read more
| Categories: Cache, Clustering, Couchbase, Games and virtual worlds, In-memory DBMS, memcached, Michael Stonebraker, MySQL, Parallelization, Theory and architecture, VoltDB and H-Store | 20 Comments |
Now we know why Vertica has been so weirdly evasive
Communicating with Vertica has been tricky recently. But HP is now announced to be buying Vertica, which pretty much forces me to comment about Vertica. 
So I’ll indulge in a little bit of explanation as to what I know about Vertica, whether for publication or under NDA. My analysis of the HP/Vertica combination, and expectations for same, will go into another post. Read more
| Categories: Analytic technologies, Data warehousing, HP and Neoview, Market share and customer counts, Michael Stonebraker, Vertica Systems | 10 Comments |
Architectural options for analytic database management systems
Mike Stonebraker recently kicked off some discussion about desirable architectural features of a columnar analytic DBMS. Let’s expand the conversation to cover desirable architectural characteristics of analytic DBMS in general. Read more
Mike Stonebraker on “real column stores”
Mike Stonebraker has a post up on Vertica’s blog trying to differentiate “real” from “pretend” column stores. (Edit: That post seems to have come back down, but as of 1/19 it can be found in Google Cache.) In essence, Mike argues that the One Right Way to design a column store is Vertica’s, a position that Daniel Abadi used to share but since has retreated from.
There are some good things about that post, and some not-so-good. The worst paragraph is probably
Several row-store vendors (including Oracle, Greenplum and Aster Data) now claim to be selling a column store. Obviously, this would require a complete rewrite of a DBMS to move from Figure 1 to Figure 2. Hence, none of the “pretenders” have actually done this. Instead all have implemented some aspects of column stores, and then claim to be the real thing. This blog defines what the “real enchilada” looks like, and how to tell it from the pretenders.
which I question on two levels. Read more
| Categories: Aster Data, Columnar database management, Database compression, Michael Stonebraker, Sybase, Theory and architecture, Vertica Systems | 24 Comments |
A few notes from XLDB 4
As much as I believe in the XLDB conferences, I only found time to go to (a big) part of one day of XLDB 4 myself. In general: Read more
| Categories: Analytic technologies, Health care, Liberty and privacy, Michael Stonebraker, MySQL, Open source, Parallelization, Petabyte-scale data management, Scientific research | 2 Comments |
Details and analysis of the VoltDB argument
Todd Hoff (High Scalability blog) posted a lengthy examination of the case and use cases for VoltDB. That excellent post, in turn, is based on a Mike Stonebraker* webinar for VoltDB, for which the slide deck is happily available. It’s all nicely consistent with what I wrote about VoltDB last month, in connection with its launch. Read more
| Categories: In-memory DBMS, Michael Stonebraker, OLTP, Parallelization, Theory and architecture, VoltDB and H-Store | 2 Comments |
VoltDB finally launches
VoltDB is finally launching today. As is common for companies in sectors I write about, VoltDB — or just “Volt” — has discovered the virtues of embargoes that end 12:01 am. Let’s go straight to the technical highlights:
- VoltDB is based on the H-Store technology, which I wrote about in February, 2009. Most of what I said about H-Store then applies to VoltDB today.
- VoltDB is a no-apologies ACID relational DBMS, which runs entirely in RAM.
- VoltDB has rather limited SQL. (One example: VoltDB can’t do SUMs in SQL.) However, VoltDB guy Tim Callaghan (Mark Callaghan’s lesser-known but nonetheless smart brother) asserts that if you code up the missing functionality, it’s almost as fast as if it were present in the DBMS to begin with, because there’s no added I/O from the handoff between the DBMS and the procedural code. (The data’s in RAM one way or the other.)
- VoltDB’s Big Conceptual Performance Story is that it does away with most locks, latches, logs, etc., and also most context switching.
- In particular, you’re supposed to partition your data and architect your application so that most transactions execute on a single core. When you can do that, you get VoltDB’s performance benefits. To the extent you can’t, you’re in two-phase-commit performance land. (More precisely, you’re doing 2PC for multi-core writes, which is surely a major reason that multi-core reads are a lot faster in VoltDB than multi-core writes.)
- VoltDB has a little less than one DBMS thread per core. When the data partitioning works as it should, you execute a complete transaction in that single thread. Poof. No context switching.
- A transaction in VoltDB is a Java stored procedure. (The early idea of Ruby on Rails in lieu of the Java/SQL combo didn’t hold up performance-wise.)
- Solid-state memory is not a viable alternative to RAM for VoltDB. Too slow.
- Instead, VoltDB lets you snapshot data to disk at tunable intervals. “Continuous” is one of the options, wherein a new snapshot starts being made as soon as the last one completes.
- In addition, VoltDB will also spool a kind of transaction log to the target of your choice. (Obvious choice: An analytic DBMS such as Vertica, but there’s no such connectivity partnership actually in place at this time.)
Flash, other solid-state memory, and disk
If there’s one subject on which the New England Database Summit changed or at least clarified my thinking,* it’s future storage technologies. Here’s what I now think:
- Solid-state memory will soon be the right storage technology for a large fraction of databases, OLTP and analytic alike. I’m not sure whether the initial cutoff in database size is best thought of as terabytes or 10s of terabytes, but it’s in that range. And it will increase over time, for the usual cheaper-parts reasons.
- That doesn’t necessarily mean flash. PCM (Phase-Change Memory) is coming down the pike, with perhaps 100X the durability of flash, in terms of the total number of writes it can tolerate. On the other hand, PCM has issues in the face of heat. More futuristically, IBM is also high on magnetic racetrack memory. IBM likes the term storage-class memory to cover all this — which I find regrettable, since the acronym SCM is way overloaded already.
- Putting a disk controller in front of solid-state memory is really wasteful. It wreaks havoc on I/O rates.
- Generic PCIe interfaces don’t suffice either, in many analytic use cases. Their I/O is better, but still not good enough. (Doing better yet is where Petascan – the stealth-mode company I keep teasing about – comes in.)
- Disk will long be useful for very large databases. Kryder’s Law, about disk capacity, has at least as high an annual improvement as Moore’s Law shows for chip capacity, the disk rotation speed bottleneck notwithstanding. Disk will long be much cheaper than silicon for data storage. And cheaper silicon in sensors will lead to ever more machine-generated data that fills up a lot of disks.
- Disk will long be useful for archiving. Disk is the new tape.
*When the first three people to the question microphone include both Mike Stonebraker and Dave DeWitt, your thinking tends to clarify in a hurry.
Related links
- A slide deck by Mohan of IBM similar to the one he presented at the NEDB Summit about storage-class memories.
- A much more detailed IBM presentation on storage-class memories.
- Oracle’s and Teradata’s beliefs about the importance of solid-state memory.
Other posts based on my January, 2010 New England Database Summit keynote address
- Data-based snooping — a huge threat to liberty that we’re all helping make worse
- Interesting trends in database and analytic technology
- Open issues in database and analytic technology
| Categories: Data warehousing, Michael Stonebraker, Presentations, Solid-state memory, Storage, Theory and architecture | 3 Comments |
New England Database Summit (January 28, 2010)
New England Database Day has now, in its third year, become a “Summit.” It’s a nice event, providing an opportunity for academics and business folks to mingle. The organizers are basically the local branch of the Mike Stonebraker research tree, with this year’s programming head being Daniel Abadi. It will be on Thursday, January 28, 2010, once again in the Stata Center at MIT. It would be reasonable to park in the venerable 4/5 Cambridge Center parking lot, especially if you’d like to eat at Legal Seafood afterwards.
So far there are two confirmed speakers — Raghu Ramakrishnan of Yahoo and me. My talk title will be something like “Database and analytic technology: The state of the union”, with all wordplay intended.
There’s more information at the official New England Database Summit website. There’s also a post with similar information on Daniel Abadi’s DBMS Musings blog.
Edit after the event:
Posts based on my January, 2010 New England Database Summit keynote address