DBMS product categories
Analysis of database management technology in specific product categories. Related subjects include:
The core challenges of OLTP are changing
I wrote a few weeks ago about the H-Store project, which rejects a variety of assumptions underlying traditional OLTP database design. One of these is long transactions over open database connections. The idea is that the most demanding OLTP applications run on the Web, where abandonment is common, and hence the only sensible option is to break things up into simple chunks. Read more
| Categories: Application areas, OLTP | Leave a Comment |
More Twitter weirdness
Twitter commonly has the problem of duplicate tweets. That is, if you post a message, it shows up twice. After a little while, the dupe disappears, but if you delete the dupe manually, the original is gone too.
I presume what’s going on is that tweets are cached, the tweets are eventually batched to disk, and they don’t always get deleted from cache until some time after they’re persisted. If you happen to check the page of your recent tweets inbetween — boom, you get two hits. But what I don’t understand is why the two versions have different timestamps.
Presumably, this could be explained at a MySQL User Conference session next month, one of whose topics will be Intelligent caching strategies using a hybrid MemCache / MySQL approach. I’m so glad they don’t use stupid strategies to do this … Read more
| Categories: Cache, MySQL, OLTP, Specific users | 3 Comments |
IBM discontinues the solidDB MySQL engine
Last year, I thought that solidDB could at least potentially be an outstanding MySQL engine. But as per news posted on SourceForge last week, that’s not going to happen. At least, it’s not going to happen via any development efforts from IBM.
| Categories: IBM and DB2, Mid-range, MySQL, Open source, solidDB | 4 Comments |
PostgreSQL can be used in a lot of different ways
The relational DBMS industry is filled with startups. In some way or other, most of them are based on or make use of the open source project PostgreSQL. (Not all, of course; exceptions include DATAllegro and Infobright, which are based on Ingres and MySQL respectively.) But how they use PostgreSQL varies greatly. Read more
| Categories: EnterpriseDB and Postgres Plus, Greenplum, Open source, PostgreSQL, Vertica Systems | 10 Comments |
Who EnterpriseDB sells to
I previously wrote that EnterpriseDB-on-Elastra has very little enterprise traction, drawing most of its interest instead from online businesses or ISVs. Having used that as a starting point in a recent chat with EnterpriseDB marketing chief Derek Rodner, I can now add that overall:
- EnterpriseDB reports good traction with ISVs. In particular, those that resell Oracle would like a cheaper alternative. Sometimes, they can port their code with no rewriting at all.
- Online businesses of various kinds also are a significant fraction of the customer base.
- EnterpriseDB has some true large-enterprise customers — Derek rattled off some household names — but this isn’t yet the heart of its business.
- EnterpriseDB has an increasing business teleselling to SMBs.
| Categories: Emulation, transparency, portability, EnterpriseDB and Postgres Plus, Mid-range | Leave a Comment |
eBay OLTP architecture
I’ve posted a couple times about eBay’s analytics side. As a companion, Don Burleson pointed me at a fascinating November, 2006 slide presentation outlining eBay’s transactional architecture and evolution. Highlights include:
- A whole lot of manual slicing of Oracle databases, so as not to exceed their capacity.
- A whole lot of careful design and ordering of transactions.
- Putting all the business logic in the application tier, with a custom O/R mapper. There’s lots of caching there, but very little state.
The presentation has a bunch of specific numbers, in case anybody wants to dive in.
| Categories: eBay, OLTP, Specific users | Leave a Comment |
The biggest eBay database
There’s been some confusion over my post about eBay’s multiple petabytes of data. So to clarify, let me say:
- eBay’s figure of >1.4 petabytes of data — for its largest single analytic database — counts disks or something, not raw user data.
- I previously published a strong conjecture that the database vendor in question was Teradata, which is definitely an eBay supplier. In particular, it is definitely not an Oracle data warehouse.
- While eBay isn’t saying who it is either — not even off-the-record — the 50%ish compression figures they experience just happen to map well to Teradata’s usual range.
- Edit: Just to be clear — not that there was any doubt, but I have reconfirmed that eBay is a Teradata user, in or including eBay’s Paypal division.
| Categories: Analytic technologies, Data warehouse appliances, Data warehousing, eBay, Specific users, Teradata | 1 Comment |
ObjectGrid versus H-Store
Billy Newport of IBM sees a lot of similarities between his app-server-based product ObjectGrid and H-Store. In both cases, constrained tree schemas are assumed, and OLTP performance goodness ensues. A couple of points I noted on a quick skim through his blog:
- He calls out RAM consumption as a challenge for this kind of architecture.
- He points out that it’s a big advantage to have data called and used in the same address space.
Being based in RAM is obviously a huge part of the H-Store scheme. But so is having transaction execution be close to the database.
IBM now has both ObjectGrid and a memory-centric DBMS (solidDB) that they’ve been using as a front end for DBMS. Integration of the two could be pretty interesting.
| Categories: Cache, IBM and DB2, Memory-centric data management, OLTP, solidDB, Theory and architecture, VoltDB and H-Store | Leave a Comment |
The architectural assumptions of H-Store
I wrote yesterday about the H-Store project, the latest from the team of researchers who also brought us C-Store and its commercialization Vertica. H-Store is designed to drastically improve efficiency in OLTP database processing, in two ways. First, it puts everything in RAM. Second, it tries to gain an additional order of magnitude on in-memory performance versus today’s DBMS designs by, for example, taking a very different approach to ensuring ACID compliance.
Today I had the chance to talk with two more of the H-Store researchers, Sam Madden and Daniel Abadi. Read more
| Categories: Database diversity, In-memory DBMS, Memory-centric data management, OLTP, VoltDB and H-Store | 5 Comments |
Mike Stonebraker calls for the complete destruction of the old DBMS order
Last week, Dan Weinreb tipped me off to something very cool: Mike Stonebraker and a group of MIT/Brown/Yale colleagues are calling for a complete rewrite of OLTP DBMS. And they have a plan for how to do it, called H-Store, as per a paper and an associated slide presentation.