Structured documents
Analysis of data management technology based on a structured-document model, or optimized for XML data. Related subjects include:
- Text data management
- Object-oriented database management
- Mark Logic
- IBM’s DB2 pureXML
- (in Text Technologies) More extensive coverage of text search
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 |
HP/Autonomy sound bites
HP has announced that:
- HP is buying Autonomy.
- HP is pulling back from WebOS.
- HP may spin off its PC business altogether.
On a high level, this means:
- HP is doubling down on enterprise IT.
- HP is taking a more software-centric approach to the enterprise IT business.
- HP is backing away from the consumer electronics business.
- HP in particular is backing away from the generic desktop/laptop PC business, which may with only moderate exaggeration be regarded as:
- The intersection of the enterprise IT and consumer electronics businesses.
- The least attractive sector of each.
My coverage of Autonomy isn’t exactly current, but I don’t know of anything that contradicts long-time competitor* Dave Kellogg’s skeptical view of Autonomy. Autonomy is a collection of businesses involved in the management, search, and retrieval of poly-structured data, in some cases with strong market share, but even so not necessarily with the strongest of reputations for technology or technology momentum. Autonomy started from a text search engine and a Bayesian search algorithm on top of that, which did a decent job for many customers. But if there’s been much in the way of impressive enhancement over the past 8-10 years, I’ve missed the news.
*Dave, of course, was CEO of MarkLogic.
Questions obviously arise about how the Autonomy acquisition relates to other HP businesses. My early thoughts include: Read more
| Categories: HP and Neoview, Market share and customer counts, Structured documents, Text, Vertica Systems | 10 Comments |
Couchbase business update
I decided I needed some Couchbase drilldown, on business and technology alike, so I had solid chats with both CEO Bob Wiederhold and Chief Architect Dustin Sallings. Pretty much everything I wrote at the time Membase and CouchOne merged to form Couchbase (the company) still holds up. But I have more detail now. 😉
Context for any comments on customer traction includes:
- Membase went into limited production release in October, and full release in January. Similar things are true of CouchDB.
- Hence, most sales of Couchbase’s products have been made over the past 6 months.
- Couchbase (the merged product) is at this point only in a pre-production developer’s release.
- Couchbase has both a direct sales force and a classic open-source “funnel”-based online selling model. Naturally, Couchbase’s understanding of what its customers are doing is more solid with respect to the direct sales base.
- Most of Couchbase’s revenue to date seems to have come from a limited number of big-ticket “lighthouse” accounts (as opposed to, say, the larger number of smaller deals that come in through the online funnel).
That said,
- Most Membase purchases are for new applications, as opposed to memcached migrations. However, customers are the kinds of companies that probably also are using memcached elsewhere.
- Most other Membase purchases are replacements for the Membase/MySQL combination. Bob says those are easy sales with short sales cycles.
- Pure memcached support is a small but non-zero business for Couchbase, and a fine source of upsell opportunities.
- In the pipeline but not so much yet in the customer base are SaaS vendors and the like who use and may want to replace traditional DBMS such as Oracle. Other than among those, Couchbase doesn’t compete much yet with Oracle et al.
- Pure CouchDB isn’t all that much of a business, at least relative to community size, as CouchDB is a single-server product commonly used by people who are content not to pay for support.
Membase sales are concentrated in five kinds of internet-centric companies, which in declining order are: Read more
Terminology: Dynamic- vs. fixed-schema databases
E. F. “Ted” Codd taught the computing world that databases should have fixed logical schemas (which protect the user from having to know about physical database organization). But he may not have been as universally correct as he thought. Cases I’ve noted in which fixed schemas may be problematic include:
- “A bunch of apps in one, similar but not the same” (in my recent post on MongoDB).
- Out-of-control product catalogs (ditto).
- Analytic use cases in which one keeps enhancing the database with derived data.
And if marketing profile analysis is ever done correctly, that will be a huge example for the list.
So what do we call those DBMS — for example NoSQL, object-oriented, or XML-based systems — that bake the schema into the applications or the records themselves? In the MongoDB post I went with “schemaless,” but I wasn’t really comfortable with that, so I took the discussion to Twitter. Comments from Vlad Didenko (in particular), Ryan Prociuk, Merv Adrian, and Roland Bouman favored the idea that schemas in such systems are changeable or late-bound, rather than entirely absent. I quickly agreed.
| Categories: Data models and architecture, NoSQL, Object, Structured documents | 46 Comments |
Terminology: poly-structured data, databases, and DBMS
My recent argument that the common terms “unstructured data” and “semi-structured data” are misnomers, and that a word like “multi-” or “poly-structured”* would be better, seems to have been well-received. But which is it — “multi-” or “poly-“?
*Everybody seems to like “poly-structured” better when it has a hyphen in it — including me. 🙂
The big difference between the two is that “multi-” just means there are multiple structures, while “poly-” further means that the structures are subject to change. Upon reflection, I think the “subject to change” part is essential, so poly-structured it is.
The definitions I’m proposing are:
- A database is poly-structured to the extent that its structure is apt to be changed in the ordinary course of query, update, or programming.
- Data is poly-structured to the extent that it is best represented in a poly-structured database.
- A DBMS is poly-structured to the extent that it is oriented to managing poly-structured databases.
| Categories: Object, Structured documents, Text, Theory and architecture | 23 Comments |
Whither MarkLogic?
My clients at MarkLogic have a new CEO, Ken Bado, even though former CEO Dave Kellogg was quite successful. If you cut through all the happy talk and side issues, the reason for the change is surely that the board wants to see MarkLogic grow faster, and specifically to move beyond its traditional niches of publishing (especially technical publishing) and national intelligence.
So what other markets could MarkLogic pursue? Before Ken even started work, I sent over some thoughts. They included (but were not limited to): Read more
| Categories: MarkLogic, Object, RDF and graphs, Structured documents | 6 Comments |
Notes on document-oriented NoSQL
When people talk about document-oriented NoSQL or some similar term, they usually mean something like:
Database management that uses a JSON model and gives you reasonably robust access to individual field values inside a JSON (JavaScript Object Notation) object.
Or, if they really mean,
The essence of whatever it is that CouchDB and MongoDB have in common.
well, that’s pretty much the same thing as what I said in the first place. 🙂
Of the various questions that might arise, three of the more definitional ones are:
- Why JSON rather than XML?
- What’s with this fluidity between the terms “document” and “object”?
- Are you serious about the lack of joins?
Let me take a crack at each. Read more
| Categories: CouchDB, MapReduce, MarkLogic, MongoDB, NoSQL, Object, Structured documents | 16 Comments |
Document-oriented DBMS without joins
When I talked with MarkLogic’s Ken Chestnut about MarkLogic 4.2, I was surprised to learn that MarkLogic really, truly doesn’t do anything like a join. Unlike some other non-SQL DBMS, MarkLogic has no SQL interface, no ODBC or JDBC. Nothing, nada. (MarkLogic has a Java interface for Xquery, but not for anything like SQL.)
| Categories: CouchDB, MarkLogic, NoSQL, Structured documents, Text, Theory and architecture | 8 Comments |
MarkLogic and its document DBMS
This post has been long in the writing for several reasons, the biggest being that I stopped working for almost a month due to family issues. Please forgive its particularly choppy writing style; having waited this long already, I now lack the patience to further clean it up.
MarkLogic:
- Is an ACID-compliant, document-oriented, non-SQL, XML-based scale-out DBMS vendor of non-trivial size and momentum.
- Still has the same technical approach I previously described.
- Recently posted an internally-written white paper with a lot of technical detail.
- Recently had a point release — MarkLogic 4.2 — a lot of which seems to be “Oh, you didn’t have that before?” kinds of stuff.
- Has given me permission to post most of the slides from same, the first few of which give a nice overview of the MarkLogic story.
- Claims 200+ each of customers and employees (that’s from a slide MarkLogic did ask me to remove from the deck).
- Is a client again.
- Not coincidentally, is interested in branching out past the vertical markets of media and government/intelligence, in particular to the financial services market.
- Has finally rationalized its company and product names so that both are now “MarkLogic.” 🙂
- Has finally grasped that if it is proud of its ACID-compliance it probably shouldn’t be trying to market itself as “NoSQL”. 🙂
Toward a NoSQL taxonomy
I talked Friday with Dwight Merriman, founder of 10gen (the MongoDB company). He more or less convinced me of his definition of NoSQL systems, which in my adaptation goes:
NoSQL = HVSP (High Volume Simple Processing) without joins or explicit transactions
Within that realm, Dwight offered a two-part taxonomy of NoSQL systems, according to their data model and replication/sharding strategy. I’d be happier, however, with at least three parts to the taxonomy:
- How data looks logically on a single node
- How data is stored physically on a single node
- How data is distributed, replicated, and reconciled across multiple nodes, and whether applications have to be aware of how the data is partitioned among nodes/shards. Read more