Teradata Unity and the idea of active-active data warehouse replication
Teradata is having its annual conference, Teradata Partners, at the same time as Oracle OpenWorld this week. That made it an easy decision for Teradata to preannounce its big news, Teradata Columnar and the rest of Teradata 14. But of course it held some stuff back, notably Teradata Unity, which is the name chosen for replication technology based on Teradata’s Xkoto acquisition.
The core mission of Teradata Unity is asynchronous, near-real-time replication across Teradata systems. The point of “asynchronous” is performance. The point of “near-real-time” is that it Teradata Unity can be used for high availability and disaster recovery, and further can be used to allow real work on HA and DR database copies. Teradata Unity works request-at-a-time, which limits performance somewhat;* Unity has a lock manager that makes sure updates are applied in the same order on all copies, in cases where locks are needed at all.
| Categories: Data warehousing, Teradata | 2 Comments |
Defining NoSQL
A reporter tweeted: “Is there a simple plain English definition for NoSQL?” After reminding him of my cynical yet accurate Third Law of Commercial Semantics, I gave it a serious try, and came up with the following. More precisely, I tweeted the bolded parts of what’s below; the rest is commentary added for this post.
NoSQL is most easily defined by what it excludes: SQL, joins, strong analytic alternatives to those, and some forms of database integrity. If you leave all four out, and you have a strong scale-out story, you’re in the NoSQL mainstream. Read more
| Categories: Cassandra, dbShards and CodeFutures, MarkLogic, MySQL, Object, Open source, Petabyte-scale data management, Schooner Information Technology | 7 Comments |
Oracle NoSQL is unlikely to be a big deal
Alex Williams noticed that there will be a NoSQL session at Oracle OpenWorld next week, and is wondering whether this will be a big deal. I think it won’t be.
There really are three major points to NoSQL.
- Dynamic schemas. This is the only one of the three that truly depends on NoSQL.
- Scale-out short-request processing. If you want to scale out efficiently at high request volumes, you’re best off not using all the flexibility SQL/relational DBMS offer. (In particular, you don’t want to do cross-node joins). Not coincidentally, a number of the best scale-out offerings were built to be NoSQL.
- Open source. Doing a relational DBMS is a big project. It seems easier to build NoSQL ones.
Oracle can address the latter two points as aggressively as it wishes via MySQL. It so happens I would generally recommend MySQL enhanced by dbShards, Schooner, and/or dbShards/Schooner, rather than Oracle-only MySQL … but that’s a detail. In some form or other, Oracle’s MySQL is a huge player in the scale-out, open source, short-request database management market.
So that leaves us with dynamic schemas. Oracle has at least four different sets of technology in that area:
- As Workday noticed years ago, MySQL can be used as a functional, basic key-value store.
- Oracle also has XML-based Berkeley DB/SleepyCat kicking around.*
- The XML extensions to Oracle’s core DBMS could be alleged to have a dynamic schema/NoSQL flavor. (Blech.)
- A dynamic schema argument could also be made for object-oriented DBMS technology. While Oracle doesn’t to my knowledge exactly sell that, it does have the Tangosol Coherence line of technology, with a potentially similar programming model.
If Oracle is now refreshing and rebranding one or more of these as “NoSQL”, there’s no reason to view that as a big deal at all.
*That’s Mike Olson’s former company, if you’re keeping score at home.
| Categories: MySQL, NoSQL, Object, OLTP, Open source, Oracle, Parallelization, Schooner Information Technology, Structured documents | 13 Comments |
Highlights of a busy news week
I put up 14 posts over the past week, so perhaps you haven’t had a chance yet to read them all. 🙂 Highlights included:
- My most important post of the week was a general guide to IT vendor strategy. That one has already spawned discussion at many companies, from the tiny to the multi-billion-dollar.
- The best comment thread of the week was probably on my post about scale-out relational OLTP choices, in which people discussed the merits of various particular alternatives.
- I recommended that people strongly consider attending XLDB 5 in Menlo Park on October 18-19.
Most of the posts, however, were reactions to news events. In particular:
- Teradata announced that Teradata 14 will be hybrid-columnar, more in Vertica’s way than in Greenplum’s or Aster Data’s. (Pay no attention to the Wall Street Journal’s apparent belief that no other analytic DBMS is hybrid-columnar at all.)
- Aster announced the unsurprising news that there will be a Teradata Aster appliance. Also, Aster talked about greater analytic flexibility in the forthcoming Aster 5.0.
- With Oracle OpenWorld coming up, Oracle decided to get some of its announcing out of the way early. In particular, it announced the Oracle Database Appliance, which is small-business-friendly hardware for running the Oracle DBMS. However, the Oracle Database Appliance doesn’t seem to do much about the complexity of running the Oracle DBMS software.
- In a catch-all Hadoop post, I noted that:
- Oracle has now clearly said it has a Hadoop appliance coming, no doubt next week at OpenWorld.
- I still can’t see why Hadoop appliances would succeed, but a lot of smart folks seem to disagree with me.
- Greenplum announced what looks like a nice but unimportant little product upgrade.
- It’s a really good thing that previously reported plans to revamp Hadoop are underway.
- DataStax announced that it really is a Cassandra company after all. Pay no attention to previous marketing that seemed to put DataStax in the same Hadoop-alternative category as, say, MapR.
- Ingres has changed its name to Actian. The announcement seems like a confession that Ingres and VectorWise are going nowhere.
| Categories: Actian and Ingres, Aster Data, Data warehousing, DataStax, Greenplum, Hadoop, Teradata, VectorWise | Leave a Comment |
Ingres deemphasized, company now named Actian
Ingres, the company, is:
- Changing its name to Actian.
- Deemphasizing Ingres, the product.
- Emphasizing a set of products that don’t exist yet (or at least aren’t shipping), namely lightweight mobile apps that are business-intelligence-plus-an-action, and technology for building them. These are called “Action Apps”, and are discussed on the Actian company blog.
- Positioning all this as something to do with “big data” (what a shock).
It turns out that Actian was the name of an ancient athletic competition commemorating Augustus’ defeat of Anthony at Actium, a battle that was more recently memorialized in the movie Cleopatra. Frankly, I think Cleopatra Software might have been a more interesting company name, although that could mean execs would have to arrive at sales calls rolled up in a carpet.
| Categories: Actian and Ingres, Business intelligence, Hadapt, Market share and customer counts, VectorWise | 10 Comments |
Workload management and RAM
Closing out my recent round of Teradata-related posts, here’s a little anomaly:
- Teradata is proud that Teradata 14’s workload management now explicitly manages I/O, to go with Teradata’s long-standing management of CPU. Teradata’s WLM still does not explicitly manage RAM.
- Aster is proud that Aster 5’s workload management now explicitly manages RAM, to go along with the WLM capabilities Aster has had for a while managing CPU and I/O. Aster’s Tasso Argyros believes this is an important capability, at least in some edge cases.
- Mike Pilcher of SAND emailed me that SAND’s WLM capabilities to explicitly manage CPU, I/O, and RAM are very well-received by the marketplace.
| Categories: Aster Data, Data warehousing, SAND Technology, Teradata, Workload management | 4 Comments |
Confusion about Teradata’s big customers
Evidently further attempts to get information on this subject would be fruitless, but anyhow:
- Teradata emailed me a couple of months ago saying something like that at that point they could count 16 petabyte-level customers. In response to my repeated requests for clarification, Teradata has explicitly refused to identify the metric used in reaching that conclusion.
- At some point Teradata did something — as per a tweet of his — to convince Neil Raden that they have 20 petabyte-class users.
- That tweet was made around the time that Teradata apparently showed a slide naming big users at the Strata conference (last week).
- If Teradata is counting the way they did three years ago, that count of 16 or 20 or whatever is probably inflated compared to, say, Vertica’s figure of 7 a few months back.
- Even so, it’s obvious — and not just from the eBay example — that Teradata has one of the most scalable analytic DBMS offerings around.
| Categories: Petabyte-scale data management, Teradata | 9 Comments |
Some notes on Hadoop (mainly) and appliances
1. EMC Greenplum has evolved its appliance product line. As I read that, the latest announcement boils down to saying that you can neatly network together various Greenplum appliances in quarter-rack increments. If you take a quarter rack each of four different things, then Greenplum says “Hooray! Our appliance is all-in-one!” Big whoop.
2. That said, the Hadoop part of EMC ‘s story is based on MapR, which so far as I can tell is actually a pretty good Hadoop implementation. More precisely, MapR makes strong claims about performance and so on, and Apache Hadoop folks don’t reply “MapR is full of &#$!” Rather, they say “We’re going to close the gap with MapR a lot faster than the MapR folks like to think — and by the way, guys, thanks for the butt-kick.” A lot more precision about MapR may be found in this M. C. Srivas SlideShare.
3. On its latest earnings call, Oracle clearly said it would introduce a Hadoop appliance, versus just hinting at a Hadoop appliance the prior quarter. The money quote was: Read more
| Categories: Data warehouse appliances, eBay, EMC, Greenplum, Hadoop, MapR, MapReduce, Open source, Oracle | 2 Comments |
DataStax pivots back to its original strategy
The DataStax and Cassandra stories are somewhat confusing. Unfortunately, DataStax chose to clarify them in what has turned out to be a crazy news week. I’m going to use this post just to report on the status of the DataStax product line, without going into any analysis beyond that.
| Categories: Cassandra, DataStax, Facebook, NoSQL, Open source | 5 Comments |
Hybrid-columnar soundbites
Busy couple of days talking with reporters. A few notes on hybrid-columnar analytic DBMS, all backed up by yesterday’s post on Teradata columnar:
- Oracle does not actually offer columnar I/O; the other three systems do. But see the “I won’t be surprised” part in yesterday’s Teradata post.
- Aster does not offer columnar compression; the other three do.
- EMC Greenplum and Teradata offer different kinds of ways to mix column and row storage in the same table; each has its advantages.
- Teradata generally has a more mature and capable offering than EMC Greenplum, for most purposes, whichever way you choose to organize your tables.
Edit: The Wall Street Journal got this wrong, writing that Teradata was the first-ever hybrid columnar system. Specifically, they wrote
While columnar technology has been around for years, Teradata says its product is unique because it allows users to include both columns and rows in the same database.
Googling on “Teradata To Unveil New Analytics Product To Speed Business Adoption” might get you around the paywall to see the offending piece.