Distinctions in SQL/Hadoop integration
Ever more products try to integrate SQL with Hadoop, and discussions of them seem confused, in line with Monash’s First Law of Commercial Semantics. So let’s draw some distinctions, starting with (and these overlap):
- Are the SQL engine and Hadoop:
- Necessarily on the same cluster?
- Necessarily or at least most naturally on different clusters?
- How, if at all, is Hadoop invoked by the SQL engine? Specifically, what is the role of:
- HDFS (Hadoop Distributed File System)?
- Hadoop MapReduce?
- HCatalog?
- How, if at all, is the SQL engine invoked by Hadoop?
In particular:
- If something is called a “connector”, then Hadoop and the SQL engine are most likely on separate clusters. Good features include (but these can partially contradict each other):
- A way of making data transfer maximally parallel.
- Query planning that is smart about when to process on the SQL engine and when to use Hadoop’s native SQL (Hive or otherwise).
- If something is called “SQL-on-Hadoop”, then Hadoop and the SQL engine are or should be on the same cluster, using the same nodes to store and process data. But while that’s a necessary condition, I’d prefer that it not be sufficient.
Let’s go to some examples. Read more
Some stuff I’m thinking about (early 2014)
From time to time I like to do “what I’m working on” posts. From my recent blogging, you probably already know that includes:
- Hadoop (always, and please see below).
- Analytic RDBMS (ditto).
- NoSQL and NewSQL.
- Specifically, SQL-on-Hadoop
- Schema-on-need.
- Spark and other memory-centric technology, including streaming.
- Public policy, mainly but not only in the area of surveillance/privacy.
- General strategic advice for all sizes of tech company.
Other stuff on my mind includes but is not limited to:
1. Certain categories of buying organizations are inherently leading-edge.
- Internet companies have adopted Hadoop, NoSQL, NewSQL and all that en masse. Often, they won’t even look at things that are conventional or expensive.
- US telecom companies have been buying 1 each of every DBMS on the market since pre-relational days.
- Financial services firms — specifically algorithmic traders and broker-dealers — have been in their own technical world for decades …
- … as have national-security agencies …
- … as have pharmaceutical research departments.
Fine. But what really intrigues me is when more ordinary enterprises also put leading-edge technologies into production. I pester everybody for examples of that.
Spark and Databricks
I’ve heard a lot of buzz recently around Spark. So I caught up with Ion Stoica and Mike Franklin for a call. Let me start by acknowledging some sources of confusion.
- Spark is very new. All Spark adoption is recent.
- Databricks was founded to commercialize Spark. It is very much in stealth mode …
- … except insofar as Databricks folks are going out and trying to drum up Spark adoption. 🙂
- Ion Stoica is running Databricks, but you couldn’t tell that from his UC Berkeley bio page. Edit: After I posted this, Ion’s bio was quickly updated. 🙂
- Spark creator and Databricks CTO Matei Zaharia is an MIT professor, but actually went on leave there before he ever showed up.
- Cloudera is perhaps Spark’s most visible supporter. But Cloudera’s views of Spark’s role in the world is different from the Spark team’s.
The “What is Spark?” question may soon be just as difficult as the ever-popular “What is Hadoop?” That said — and referring back to my original technical post about Spark and also to a discussion of prominent Spark user ClearStory — my try at “What is Spark?” goes something like this:
- Spark is a distributed execution engine for analytic processes …
- … which works well with Hadoop.
- Spark is distinguished by a flexible in-memory data model …
- … and farms out persistence to HDFS (Hadoop Distributed File System) or other existing data stores.
- Intended analytic use cases for Spark include:
- SQL data manipulation.
- ETL-like data manipulation.
- Streaming-like data manipulation.
- Machine learning.
- Graph analytics.
More on public policy
Occasionally I take my public policy experience out for some exercise. Last week I wrote about privacy and network neutrality. In this post I’ll survey a few more subjects.
1. Censorship worries me, a lot. A classic example is Vietnam, which basically has outlawed online political discussion.
And such laws can have teeth. It’s hard to conceal your internet usage from an inquisitive government.
2. Software and software related patents are back in the news. Google, which said it was paying $5.5 billion or so for a bunch of Motorola patents, turns out to really have paid $7 billion or more. Twitter and IBM did a patent deal as well. Big numbers, and good for certain shareholders. But this all benefits the wider world — how?
The purpose of legal intellectual property protections, simply put, is to help make it a good decision to create something. …
Why does “securing … exclusive Right[s]” to the creators of things that are patented, copyrighted, or trademarked help make it a good decision for them to create stuff? Because it averts competition from copiers, thus making the creator a monopolist in what s/he has created, allowing her to at least somewhat value-price her creation.
I.e., the core point of intellectual property rights is to prevent copying-based competition. By way of contrast, any other kind of intellectual property “right” should be viewed with great suspicion.
That Constitutionally-based principle makes as much sense to me now as it did then. By way of contrast, “Let’s give more intellectual property rights to big corporations to protect middle-managers’ jobs” is — well, it’s an argument I view with great suspicion.
But I find it extremely hard to think of a technology industry example in which development was stimulated by the possibility of patent protection. Yes, the situation may be different in pharmaceuticals, or for gadgeteering home inventors, but I can think of no case in which technology has been better, or faster to come to market, because of the possibility of a patent-law monopoly. So if software and business-method patents were abolished entirely — even the ones that I think could be realistically adjudicated — I’d be pleased.
3. In November, 2008 I offered IT policy suggestions for the incoming Obama Administration, especially: Read more
| Categories: Buying processes, Google, IBM and DB2, Public policy, Surveillance and privacy | 1 Comment |
The games of Watson
IBM excels at game technology, most famously in Deep Blue (chess) and Watson (Jeopardy!). But except at the chip level — PowerPC — IBM hasn’t accomplished much at game/real world crossover. And so I suspect the Watson hype is far overblown.
I believe that for two main reasons. First, whenever IBM talks about big initiatives like Watson, it winds up bundling a bunch of dissimilar things together and claiming they’re a seamless whole. Second, some core Watson claims are eerily similar to artificial intelligence (AI) over-hype three or more decades past. For example, the leukemia treatment advisor that is being hopefully built in Watson now sounds a lot like MYCIN from the early 1970s, and the idea of collecting a lot of tidbits of information sounds a lot like the Cyc project. And by the way:
- MYCIN led to E-MYCIN, which led to the company Teknowledge, which raised a lot of money* but now has almost faded from memory.
- Cyc is connected to the computer science community’s standard unit of bogosity.
| Categories: Health care, IBM and DB2, Scientific research, Text | 3 Comments |
Notes on memory-centric data management
I first wrote about in-memory data management a decade ago. But I long declined to use that term — because there’s almost always a persistence story outside of RAM — and coined “memory-centric” as an alternative. Then I relented 1 1/2 years ago, and defined in-memory DBMS as
DBMS designed under the assumption that substantially all database operations will be performed in RAM (Random Access Memory)
By way of contrast:
Hybrid memory-centric DBMS is our term for a DBMS that has two modes:
- In-memory.
- Querying and updating (or loading into) persistent storage.
These definitions, while a bit rough, seem to fit most cases. One awkward exception is Aerospike, which assumes semiconductor memory, but is happy to persist onto flash (just not spinning disk). Another is Kognitio, which is definitely lying when it claims its product was in-memory all along, but may or may not have redesigned its technology over the decades to have become more purely in-memory. (But if they have, what happened to all the previous disk-based users??)
Two other sources of confusion are:
- The broad variety of memory-centric data management approaches.
- The over-enthusiastic marketing of SAP HANA.
With all that said, here’s a little update on in-memory data management and related subjects.
- I maintain my opinion that traditional databases will eventually wind up in RAM.
- At conventional large enterprises — as opposed to for example pure internet companies — production deployments of HANA are probably comparable in number and investment to production deployments of Hadoop. (I’m sorry, but much of my supporting information for that is confidential.)
- Cloudera is emphatically backing Spark. And a key aspect of Spark is that, unlike most of Hadoop, it’s memory-centric.
- It has become common for disk-based DBMS to persist data through a “log-structured” architecture. That’s a whole lot like what you do for persistence in a fundamentally in-memory system.
- I’m also sensing increasing comfort with the strategy of committing writes as soon as they’ve been acknowledged by two or more nodes in RAM.
And finally,
- I’ve never heard a story about an in-memory DBMS actually losing data. It’s surely happened, but evidently not often.
DataStax/Cassandra update
Cassandra’s reputation in many quarters is:
- World-leading in the geo-distribution feature.
- Impressively scalable.
- Hard to use.
This has led competitors to use, and get away with, sales claims along the lines of “Well, if you really need geo-distribution and can’t wait for us to catch up — which we soon will! — you should use Cassandra. But otherwise, there are better choices.”
My friends at DataStax, naturally, don’t think that’s quite fair. And so I invited them — specifically Billy Bosworth and Patrick McFadin — to educate me. Here are some highlights of that exercise.
DataStax and Cassandra have some very impressive accounts, which don’t necessarily revolve around geo-distribution. Netflix, probably the flagship Cassandra user — since Cassandra inventor Facebook adopted HBase instead — actually hasn’t been using the geo-distribution feature. Confidential accounts include:
- A petabyte or so of data at a very prominent company, geo-distributed, with 800+ nodes, in a kind of block storage use case.
- A messaging application at a very prominent company, anticipated to grow to multiple data centers and a petabyte of so of data, across 1000s of nodes.
- A 300 terabyte single-data-center telecom account (which I can’t find on DataStax’s extensive customer list).
- A huge health records deal.
- A Fortune 10 company.
DataStax and Cassandra won’t necessarily win customer-brag wars versus MongoDB, Couchbase, or even HBase, but at least they’re strongly in the competition.
DataStax claims that simplicity is now a strength. There are two main parts to that surprising assertion. Read more
Vertica 7
It took me a bit of time, and an extra call with Vertica’s long-time R&D chief Shilpa Lawande, but I think I have a decent handle now on Vertica 7, code-named Crane. The two aspects of Vertica 7 I find most interesting are:
- Flex Zone, a schema-on-need technology very much like Hadapt’s (but of course with access to Vertica performance).
- What sounds like an alternate query execution capability for short-request queries, the big point of which is that it saves them from being broadcast across the whole cluster, hence improving scalability. (Adding nodes of course doesn’t buy you much for the portion of a workload that’s broadcast.)
Other Vertica 7 enhancements include:
- A lot of Bottleneck Whack-A-Mole.
- “Significant” improvements to the Vertica management console.
- Security enhancements (Kerberos), Hadoop integration enhancements (HCatalog), and enhanced integration with Hadoop security (Kerberos again).
- Some availability hardening. (“Fault groups”, which for example let you ensure that data is replicated not just to 2+ nodes, but also that the nodes aren’t all on the same rack.)
- Java as an option to do in-database analytics. (Who knew that feature was still missing?)
- Some analytic functionality. (Approximate COUNT DISTINCT, but not yet Approximate MEDIAN.)
Overall, two recurring themes in our discussion were:
- Load and ETL (Extract/Transform/Load) performance, and/or obviating ETL.
- Short-request performance, in the form of more scalable short-request concurrency.
SaaS appliances, SaaS data centers, and customer-premises SaaS
Conclusions
I think that most sufficiently large enterprise SaaS vendors should offer an appliance option, as an alternative to the core multi-tenant service. In particular:
- SaaS appliances address customer fears about security, privacy, compliance, performance isolation, and lock-in.
- Some of these benefits occur even if the appliance runs in the same data centers that host the vendor’s standard multi-tenant SaaS. Most of the rest occur if the customer can choose a co-location facility in which to place the appliance.
- Whether many customers should or will use the SaaS appliance option is somewhat secondary; it’s a check-mark item. I.e., many customers and prospects will be pleased that the option at least exists.
How I reached them
Core reasons for selling or using SaaS (Software as a Service) as opposed to licensed software start:
- The SaaS vendor handles all software upgrades, and makes them promptly. In principle, this benefit could also be achieved on a dedicated system on customer premises (or at the customer’s choice of co-location facility).
- In addition, the SaaS vendor handles all the platform and operational stuff — hardware, operating system, computer room, etc. This benefit is antithetical to direct customer control.
- The SaaS vendor only has to develop for and operate on a tightly restricted platform stack that it knows very well. This benefit is also enjoyed in the case of customer-premises appliances.
Conceptually, then, customer-premises SaaS is not impossible, even though one of the standard Big Three SaaS benefits is lost. Indeed:
- Microsoft Windows and many other client software packages already offer to let their updates be automagically handled by the vendor.
- In that vein, consumer devices such as game consoles already are a kind of SaaS appliance.
- Complex devices of any kind, including computers, will see ever more in the way of “phone-home” features or optional services, often including routine maintenance and upgrades.
But from an enterprise standpoint, that’s all (relatively) simple stuff. So we’re left with a more challenging question — does customer-premises SaaS make sense in the case of enterprise applications or other server software?
| Categories: Data warehouse appliances, HP and Neoview, salesforce.com, Software as a Service (SaaS), Surveillance and privacy | 6 Comments |
Thoughts on SaaS
Generalizing about SaaS (Software as a Service) is hard. To prune some of the confusion, let’s start by noting:
- SaaS has been around for over half a century, and at times has been the dominant mode of application delivery.
- The term multi-tenancy is being used in several different ways.
- Multi-tenancy, in the purest sense, is inessential to SaaS. It’s simply an implementation choice that has certain benefits for the SaaS provider. And by the way, …
- … salesforce.com, the chief proponent of the theory that true multi-tenancy is the hallmark of true SaaS, abandoned that position this week.
- Internet-based services are commonly, if you squint a little, SaaS. Examples include but are hardly limited to Google, Twitter, Dropbox, Intuit, Amazon Web Services, and the company that hosts this blog (KnownHost).
- Some of the core arguments for SaaS’ rise, namely the various efficiencies of data center outsourcing and scale, apply equally to the public cloud, to SaaS, and to AEaaS (Anything Else as a Service).
- These benefits are particularly strong for inherently networked use cases. For example, you really don’t want to be hosting your website yourself. And salesforce.com got its start supporting salespeople who worked out of remote offices.
- In theory and occasionally in practice, certain SaaS benefits, namely the outsourcing of software maintenance and updates, could be enjoyed on-premises as well. Whether I think that could be a bigger deal going forward will be explored in future posts.
For smaller enterprises, the core outsourcing argument is compelling. How small? Well:
- What’s the minimum level of IT operations headcount needed for mission-critical systems? Let’s just say “several”.
- What does that cost? Fully burdened, somewhere in the six figures.
- What fraction of the IT budget should such headcount be? As low a double digit percentage as possible.
- What fraction of revenues should be spent on IT? Some single-digit percentage.
So except for special cases, an enterprise with less than $100 million or so in revenue may have trouble affording on-site data processing, at least at a mission-critical level of robustness. It may well be better to use NetSuite or something like that, assuming needed features are available in SaaS form.*