Many kinds of memory-centric data management
I’m frequently asked to generalize in some way about in-memory or memory-centric data management. I can start:
- The desire for human real-time interactive response naturally leads to keeping data in RAM.
- Many databases will be ever cheaper to put into RAM over time, thanks to Moore’s Law. (Most) traditional databases will eventually wind up in RAM.
- However, there will be exceptions, mainly on the machine-generated side. Where data creation and RAM data storage are getting cheaper at similar rates … well, the overall cost of RAM storage may not significantly decline.
Getting more specific than that is hard, however, because:
- The possibilities for in-memory data storage are as numerous and varied as those for disk.
- The individual technologies and products for in-memory storage are much less mature than those for disk.
- Solid-state options such as flash just confuse things further.
Consider, for example, some of the in-memory data management ideas kicking around. Read more
Clarifying IBM DB2 Express-C crippleware
When Conor O’Mahony briefed me about DB2 10, he kept commenting that cool features he was talking about could be found in all editions of DB2, even the free one. So I asked what the limitations were on free DB2. He researched the matter and got back to me — and they sounded like what appeared to have been the limits when free DB2 was first introduced, over 6 years ago.
I tweeted about this, and was very fortunate that Ian Bjorhovde spoke up and said it wasn’t correct. Some scrambling ensued. It seems that the main sources of error were:
- People tend to confuse DB2 Express and DB2 Express-C; only the latter is free.
- What IBM said about the limitations DB2 Express-C upon its introduction 6 years ago should not be interpreted in line with what a plain reading might suggest.
In particular, we shouldn’t take IBM’s repeated 2006 statements that
DB2 Express-C may be deployed on … on AMD or Intel x86 systems with up to 2 dual-core chips. 4 GB of memory is the maximum supported.
to mean that you were ever allowed to use DB2 Express-C with 4 cores, nor with 4 GB of RAM.
To clarify things, Conor sent over email with permission to quote, as follows: Read more
| Categories: IBM and DB2, Pricing | 11 Comments |
IBM DB2 10
Shortly before Tuesday’s launch of DB2 10, IBM’s Conor O’Mahony checked in for a relatively non-technical briefing.* More precisely, this is about DB2 for “distributed” systems, aka LUW (Linux/Unix/Windows); some of the features have already been in the mainframe version of DB2 for a while. IBM is graciously permitting me to post the associated DB2 10 announcement slide deck.
*I hope any errors in interpretation are minor.
Major aspects of DB2 10 include new or improved capabilities in the areas of:
- Compression.
- Analytic query performance.
- Data ingest.
- Multi-temperature data management.
- Workload management.
- Graph management/relationship analytics.
- Time-travel, bitemporal features, and bitemporal time-travel.
Of course, there are various other enhancements too, including to security (fine-grained access control), Oracle compatibility, and DB2 pureScale. Everything except the pureScale part is also reflected in IBM InfoSphere Warehouse, which is a near-superset of DB2.*
*Also, the data ingest part isn’t in base DB2.
| Categories: Data warehousing, Database compression, IBM and DB2, RDF and graphs, Solid-state memory, Workload management | 3 Comments |
Our clients, and where they are located
From time to time, I disclose our vendor client lists. Another iteration is below, the first since a little over a year ago. To be clear:
- This is a list of Monash Advantage members.
- All our vendor clients are Monash Advantage members, unless …
- … we work with them primarily in their capacity as technology users. (A large fraction of our user clients happen to be SaaS vendors.)
- We do not usually disclose our user clients.
- We do not usually disclose our venture capital clients, nor those who invest in publicly-traded securities.
- Excluded from this round of disclosure is one vendor I have never written about.
- Included in this round of disclosure is one client paying for services partly in stock. All our other clients are cash-only.
For reasons explained below, I’ll group the clients geographically. Obviously, companies often have multiple locations, but this is approximately how it works from the standpoint of their interactions with me. Read more
DataStax Enterprise and Cassandra revisited
My last post about DataStax Enterprise and Cassandra didn’t go so well. As follow-up, I chatted for two hours with Rick Branson and Billy Bosworth of DataStax. Hopefully I can do better this time around.
For starters, let me say there are three kinds of data management nodes in DataStax Enterprise:
- Vanilla Cassandra.
- Cassandra plus Solr. Solr is a superset of the text-indexing system Lucene.
- Solr adds a lot more secondary indexing to Cassandra.
- In addition, these nodes serve as Solr emulation; you can run generic Solr apps on them.
- Cassandra plus Hadoop.
- You can use Hadoop MapReduce to manipulate generic Cassandra data.
- In addition, these nodes serve as Hadoop/HDFS (Hadoop Distributed File System) emulation; you can run generic Hadoop apps on them.
- Hadoop jobs can interweave access to the two kinds of data structure.
Cassandra, Solr, Lucene, and Hadoop are all Apache projects.
If we look at this from the standpoint of DML (Data Manipulation Language) and data access APIs:
- Cassandra is a column-group kind of NoSQL DBMS. You can get at its data programmatically.
- There’s something called CQL (Cassandra Query Language), said to be SQL-like.
- There’s a JDBC driver for CQL.
- With Hadoop MapReduce also come Hive, Pig, and Sqoop.
- With Solr and Lucene come full-text search.
In addition, it is sometimes recommended that you use “in-entity caching”, where an entire data structure (e.g. in JSON) winds up in a single Cassandra column.
The two main ways to get direct SQL* access to data in DataStax Enterprise are:
- JDBC/SQL.
- Hive/Hadoop.
*or very SQL-like, depending on how you view things
Before going further, let’s recall some Cassandra basics: Read more
| Categories: Cassandra, DataStax, Hadoop, MapReduce, Market share and customer counts, NoSQL, Open source, Text | 5 Comments |
CodeFutures/dbShards update
I’ve been talking a fair bit with Cory Isaacson, CEO of my client CodeFutures, which makes dbShards. Business notes include:
- 7 production users, plus an 8th imminent.
- 12-14 signed contracts beyond that.
- ~160 servers in production.
- One customer who has almost 15 terabytes of data (in the cloud).
- Still <10 people, pretty much all engineers.
- Profitable, but looking to raise a bit of growth capital.
Apparently, the figure of 6 dbShards customers in July, 2010 is more comparable to today’s 20ish contracts than to today’s 7-8 production users. About 4 of the original 6 are in production now.
NDA stuff aside, the main technical subject we talked about is something Cory calls “relational sharding”. The point is that dbShards’ transparent sharding can be done in such a way as to make many joins be single-server. Specifically:
- When a table is sufficiently small to be replicated in full at every nodes, you can join on it without moving data across the network.
- When two tables are sharded on the same key, you can join on that key without moving data across the network.
dbShards can’t do cross-shard joins, but it can do distributed transactions comprising multiple updates. Cory argues persuasively that in almost all cases this is enough; but I see cross-shard joins as a feature that should someday be added to dbShards even so.
The real issue with dbShards’ transparent sharding is ensuring it’s really transparent. Cory regards as typical a customer with a couple thousand tables, who had to change a dozen or so SQL statements to implement dbShards. But there are near-term plans to automate the number of SQL changes needed down to 0. The essence of that change is this: Read more
| Categories: Clustering, Data integration and middleware, Data models and architecture, dbShards and CodeFutures, Market share and customer counts | Leave a Comment |
Notes on the ClearStory Data launch, including an inaccurate quote from me
ClearStory Data launched, with nice coverage in the New York Times, Computerworld, and elsewhere. But from my standpoint, there were some serious problems:
- (Bad.) I was planning to cover the launch as well, in a split exclusive, but that plan was changed, costing me considerable wasted work.
- (Worse.) I wasn’t told of the change as soon as it was known. Indeed, I wasn’t told at all; I was left to infer it from the fact that I was now being asked to talk with other reporters.
- (Horrific.) I was quoted in the ClearStory launch press release, but while the sentiments were reasonably in line with my own, the quote was incorrect.*
I’m utterly disgusted with this whole mess, although after talking with her a lot I’m fine with CEO Sharmila Mulligan’s part in it, which is to say with ClearStory’s part in general.
*I avoid the term “platform” as much as possible; indeed, I still don’t really know what the “new platforms” part was supposed to refer to. The Frankenquote wound up with some odd grammar as well.
Actually, in principle I’m a pretty close adviser to ClearStory (for starters, they’re one of my stealth-mode clients). That hasn’t really ramped up yet; in particular, I haven’t had a technical deep dive. So for now I’ll just say:
| Categories: Business intelligence, ClearStory Data, Data integration and middleware, Data mart outsourcing | Leave a Comment |
DataStax Enterprise 2.0
Edit: Multiple errors in the post below have been corrected in a follow-on post about DataStax Enterprise and Cassandra.
My client DataStax is announcing DataStax Enterprise 2.0. The big point of the release is that there’s a bunch of stuff integrated together, including at least:
- Cassandra — the NoSQL DBMS, which DataStax sometimes calls “DataStax Server”. Edit: That’s not really a fair criticism of DataStax’s messaging.
- Hadoop MapReduce, which DataStax sometimes calls “Hadoop”. Edit: That is indeed fair.
- Sqoop — the general way to connect relational DBMS to Hadoop, which DataStax sometimes calls “RDBMS integration”.
- Solr — the search-centric Apache project, or big parts of it, which DataStax generally calls either “Solr” or “Solr compatibility”.
- log4j – an Apache project that has something or other to do with logging, or parts of it, which DataStax sometimes calls “log file integration”.
- DataStax OpsCenter — some management tools and so on around Cassandra and the rest of the product line.
DataStax stresses that all this runs on the same cluster, with the same administrative tools and so on. For example, on a single cluster:
- You can manage the interactive data for a web site.
- You can store the logs for that website.
- You can analyze all of the above in Hadoop.
Comments on Oracle’s third quarter 2012 earnings call
Various reporters have asked me about Oracle’s third quarter 2012 earnings conference call. Specific Q&A includes:
What did Oracle do to have its earnings beat Wall Street’s estimates?
Have a bad second quarter and then set Wall Street’s expectations too low for Q3. This isn’t about strong results; it’s about modest expectations.
Can Oracle be a leader in both hardware and software?
- It’s not inconceivable.
- The observation that Oracle, IBM, and Teradata all are pushing hardware-software combinations has been intriguing ever since IBM bought Netezza. (SAP really isn’t, however; ditto Microsoft.)
- I do think Oracle may be somewhat overoptimistic as to how cooperative the Sun user base will be in buying more high-end product and in paying more in maintenance for the gear they already have.
Beyond that, please see below.
What about Oracle in the cloud?
MySQL is an important cloud supplier. But Oracle overall hasn’t demonstrated much understanding of what cloud technology and business are all about. An expensive SaaS acquisition here or there could indeed help somewhat, but it seems as if Oracle still has a very long way to go.
Other comments
Other comments on the call, whose transcript is available, include: Read more
| Categories: Cloud computing, Exadata, Humor, In-memory DBMS, Oracle, SAP AG, Software as a Service (SaaS) | 5 Comments |
Akiban update
I have a bunch of backlogged post subjects in or around short-request processing, based on ongoing conversations with my clients at Akiban, Cloudant, Code Futures (dbShards), DataStax (Cassandra) and others. Let’s start with Akiban. When I posted about Akiban two years ago, it was reasonable to say:
- Akiban is in the short-request DBMS business.
- MySQL compatibility is one way to access Akiban, but it’s not the whole story.
- Akiban’s main point of technical differentiation is to arrange data hierarchically on disk so that many joins are “zero-cost”.
- Walking the hierarchy isn’t a great way to get at data for every possible query; Akiban recognizes the need for other access techniques as well.
All of the above are still true. But unsurprisingly, plenty of the supporting details have changed. Read more
| Categories: Akiban, Data models and architecture, MySQL, Object | 5 Comments |