MOLAP
Analysis of MOLAP (Multidimensional OnLine Analytic Processing) products and vendors. Related subjects include:
- Cognos (which now owns TM1)
- Oracle (which now owns Essbase)
- Microsoft (which offers Microsoft Analysis Services)
- Data warehousing
Defining and surveying “Memory-centric data management”
I’m writing more and more about memory-centric data management technology these days, including in my latest Computerworld column. You may be wondering what that term refers to. Well, I’ve basically renamed what are commonly called “in-memory DBMS,” for what I think is a very good reason: Most of the products in the category aren’t true DBMS, aren’t wholly in-memory, or both! Indeed, if you catch me in a grouchy mood I might argue that “in-memory DBMS” is actually a contradiction in terms.
I’ll give a quick summary of the vendors and products I am focusing on in this newly-named category, and it should be clearer what I mean:
- TimesTen (now owned by Oracle): TimesTen is the quintessentional “in-memory DBMS.” It’s a fairly full relational DBMS, but if you want to persist memory to disk it has to be handed off to a conventional DBMS. Historically, that has usually been MySQL or Oracle. TimesTen’s biggest market penetration has been in financial trading.
- Solid Information Technology‘s BoostEngine: Solid is a Finnish company (or was — it’s pretty American now) specializing in embedded DBMS sold mainly for telecommunication uses. Big OEM customers include several well-known telecom equipment manufacturers and HP (for OpenView). “Embedded” often means no DBA, no monitor, no keyboard — they box manufacturer installs it and there it stays for the life of the product. Solid has to offer strong replication capabilities, since its products are often used in highly distributed (e.g., multiblade, multibox) environments. So it’s taken the next step and exploited the replication by allowing customers to use some instances of the product disklessly.
- Event-stream products from Streambase and Progress: The canonical application for event-stream products is automating financial trading decisions based on the flow of market information. Mike Stonebraker, the brains behind Streambase, has recently popularized the idea; Progress bought Apama, who actually have been in the business longer. These applications require even more speed than the financial trading apps that TimesTen handles, and they discard most of the information they look at. In-memory is the only way to go.
- Progress’s ObjectStore: ObjectStore comes from the company Object Design, which merged into Excelon, which was acquired by Progress. It’s really a toolkit for building DBMS and similar systems, which is why it’s at various times been marketed as an OODBMS and an XML DBMS, without a lot of success either way. But there have been a few sterling apps built in ObjectStore even so, including a key part of the Amazon bookstore Despite this limited market success, a significant fraction of Progress’s best engineering talent has moved over to the Real-Time Division to focus on ObjectStore and other memory-centric products. The memory-centric aspect of ObjectStore is this: ObjectStore’s big virtue is that it gets objects from disk to memory and vice-versa very efficiently, then distributes and caches them around a network as needed. This was originally invented for client/server processing, but works fine in a multi-server thin client setup as well. And object processing, of course, relies on a whole lot of pointers. And pointer-chasing is pretty much the worst way to deal with the disk speed barrier, unless you do it in main memory.
- Applix‘s TM1: Like many companies in the analytics area, Applix has had trouble deciding whether it sells applications, BI system software, or both. But in any case its core technology is TM1, a memory-centric MOLAP offering. Traditional MOLAP products reside on the horns of a nasty dilemma: They rely on precalculation to give good performance, but that causes ghastly database explosion. Applix gets out of this problem by doing no precalculation whatsoever, loading the data into main memory, and executing all queries on the fly.
- SAP’s BI Accelerator: SAP is building out an elaborate technology stack with NetWeaver, especially in the BI area. One important aspect is that the full data warehouse is logically broken (or copied) into a series of data marts called “InfoCubes.” BI Accelerator takes the logical next step, loading an entire InfoCube into main memory. Almost every query is executed via a full table scan, which would be insane on disk but makes perfect sense when the data is already in RAM.
So there you have it. There are a whole lot of technologies out there that manage data in RAM, in ways that would make little or no sense if disks were more intimately involved. Conventional DBMS also try to exploit RAM and limit disk access, via caching; but generally the data access methods they use in RAM are pretty similar to those they use when going out to disk. So memory-centric systems can have a major advantage.
The end of the single-server DBMS vendor
For all practical purposes, there are no DBMS vendors left advocating single-server strategies. Oracle was the last one, but it just acquired in-memory data management vendor TimesTen, which will be used as a cache in front of high-performance Oracle databases. (It will also continue to be sold for stand-alone uses, especially in the financial trading and defense/intelligence markets.)
IBM’s Viper is a server-and-a-half story, with lots of integration over a dual-server (one relational, one native XML) base. IBM also is moving aggressively in data integration/federation, with Ascential and many other acquisitions. It also sells a broad range of database products itself, including two DB2s, several Informix products, and so on.
Microsoft also has a multi-server strategy. In its case, relational, text, and MOLAP storage are more separate than in Oracle’s or even IBM’s products; again, there’s a thick layer of technology on top integrating them. An eventual move to native XML storage will, one must imagine, be handled in the same way.
Smaller vendors Sybase and Progress also offer multiple DBMS each.
Teradata is a pretty big player with only one DBMS — but it’s specialized for data warehousing. Teradata is the first to tell you you should use something else for your classical transaction processing.
The Grand Unified Integrated Database theory is, so far as I can tell, quite dead. Some people just refuse to admit that fact.
| Categories: Database diversity, IBM and DB2, In-memory DBMS, Microsoft and SQL*Server, MOLAP, Oracle, Progress, Apama, and DataDirect, Sybase, Teradata, Theory and architecture | 3 Comments |
Down with database consolidation!
As with all changes in information technology, the move to DBMS2 will largely be one of evolution. But it does have a couple of revolutionary aspects.
Short-term, the biggest change is a renunciation of database and DBMS vendor consolidation. Consolidation never has worked, it never will work, and as data integration technologies keep improving it’s not that important anyway.
IBM and Oracle offer really great, brilliantly complex data warehousing technology. But if you want the most bang for the buck, forget about them, and go instead with a specialty vendor. Depending on the specifics of your situation, Teradata, Netezza, Datallego, WhiteCross, or SAP may offer the best choice, and that list could be even longer.
Similarly, for generic OLTP data management, cheap and/or open source options are getting ever more attractive. Microsoft is a serious contender for applications that previously only Oracle and IBM could handle, while MySQL and maybe Ingres are moving up the food chain right behind.
In many cases, these alternative technologies are lower-cost across the board: Lower purchase price, lower ongoing maintenance fees, and lower administrative costs.
So what, again, is the case for consolidation?
| Categories: Actian and Ingres, Analytic technologies, Data warehouse appliances, Database diversity, IBM and DB2, Kognitio, Memory-centric data management, Microsoft and SQL*Server, MOLAP, MySQL, Netezza, Open source, Oracle, SAP AG, Theory and architecture | Comments Off on Down with database consolidation! |