Analysis of database management systems designed with a focus on OTLP (OnLine Transaction Processing) uses.
In a call Monday with a prominent company, I was told:
- Teradata, Netezza, Greenplum and Vertica aren’t relational.
- Teradata, Netezza, Greenplum and Vertica are all data warehouse appliances.
That, to put it mildly, is not accurate. So I shall try, yet again, to set the record straight.
In an industry where people often call a DBMS just a “database” — so that a database is something that manages a database! — one may wonder why I bother. Anyhow …
1. The products commonly known as Oracle, Exadata, DB2, Sybase, SQL Server, Teradata, Sybase IQ, Netezza, Vertica, Greenplum, Aster, Infobright, SAND, ParAccel, Exasol, Kognitio et al. all either are or incorporate relational database management systems, aka RDBMS or relational DBMS.
2. In principle, there can be difficulties in judging whether or not a DBMS is “relational”. In practice, those difficulties don’t arise — yet. Every significant DBMS still falls into one of two categories:
- Was designed to do relational stuff* from the get-go, even if it now does other things too.
- Supports a lot of SQL.
- Was designed primarily to do non-relational things.*
- Doesn’t support all that much SQL.
*I expect the distinction to get more confusing soon, at which point I’ll adopt terms more precise than “relational things” and “relational stuff”.
3. There are two chief kinds of relational DBMS: Read more
It feels like time to write about Clustrix, which I last covered in detail in May, 2010, and which is releasing Clustrix 4.0 today. Clustrix and Clustrix 4.0 basics include:
- Clustrix makes a short-request processing appliance.
- As you might guess from the name, Clustrix is clustered — peer-to-peer, with no head node.
- The Clustrix appliance uses flash/solid-state storage.
- Traditionally, Clustrix has run a MySQL-compatible DBMS.
- Clustrix 4.0 introduces JSON support. More on that below.
- Clustrix 4.0 introduces a bunch of administrative features, and parallel backup.
- Also in today’s announcement is a Rackspace partnership to offer Clustrix remotely, at monthly pricing.
- Clustrix has been shipping product for about 4 years.
- Clustrix has 20 customers in production, running >125 Clustrix nodes total.
- Clustrix has 60 people.
- List price for a (smallest size) Clustrix system is $150K for 3 nodes. Highest-end maintenance costs 15%.
- There’s also a $100K version meant for high availability/disaster recovery. Over half of Clustrix’s customers use off-site disaster recovery.
- Clustrix is raising a C round. Part of it has already been raised from insiders, as a kind of bridge.
The biggest Clustrix installation seems to be 20 nodes or so. Others seem to have 10+. I presume those disaster recovery customers have 6 or more nodes each. I’m not quite sure how the arithmetic on that all works; perhaps the 125ish count of nodes is a bit low.
Clustrix technical notes include: Read more
|Categories: Cloud computing, Clustering, Clustrix, Database compression, Market share and customer counts, MySQL, OLTP, Pricing, Structured documents||4 Comments|
From time to time, I try to step back and build a little taxonomy for the variety in database technology. One effort was 4 1/2 years ago, in a pre-planned exchange with Mike Stonebraker (his side, alas, has since been taken down). A year ago I spelled out eight kinds of analytic database.
The angle I’ll take this time is to say that every sufficiently large enterprise needs to be cognizant of at least 7 kinds of database challenge. General notes on that include:
- I’m using the weasel words “database challenge” to evade questions as to what is or isn’t exactly a DBMS.
- One “challenge” can call for multiple products and technologies even within a single enterprise, let alone at different ones. For example, in this post the “eight kinds of analytic database” are reduced to just a single category.
- Even so, one product or technology may be well-suited to address a couple different kinds of challenges.
The Big Seven database challenges that almost any enterprise faces are: Read more
|Categories: Data integration and middleware, Data models and architecture, Database diversity, EAI, EII, ETL, ELT, ETLT, Hadoop, Memory-centric data management, NoSQL, Object, OLTP, RDF and graphs, Structured documents, Talend, Text||3 Comments|
Surprisingly often, I’m asked “Is salesforce.com going to stick with Oracle?” So let me refer to and expand upon my previous post about salesforce.com’s database architecture by saying:
- Today, salesforce.com uses Oracle as one of several ways to store data.
- salesforce.com’s use of Oracle isn’t very relational.
- salesforce.com is investing in HBase, after exploring other NoSQL options.
- salesforce.com surely has a very inexpensive Oracle license, reducing pressure to move any time soon. However …
- … salesforce.com’s use of Oracle has flipped from being a marketing advantage to a marketing liability.*
- It will be some years before any NoSQL option is mature enough to handle salesforce.com’s work.
- Especially through Heroku, salesforce.com is getting ever more experience with PostgreSQL.
Some day, Marc Benioff will probably say “We turned off Oracle across most of our applications a while ago, and nobody outside the company even noticed.”
- The marketing benefit “Oracle — it’s what the trustworthy big boys use” hardly matters any more.
- The marketing annoyance of Larry Ellison citing salesforce.com’s use of Oracle keeps growing.
Note: This blog post is less readable than it would be if I’d found a better workaround to WordPress’ bugs in the area of nested bullet points. I’m sorry.
I talked with MemSQL shortly before today’s launch. MemSQL technology basics are:
- In-memory relational DBMS.
- Being released single-box only. Transparent sharding is under development for release in the fall. Basic replication is under development too.
- Subset of SQL-92.
- MySQL wire-compatible (SQL coverage issues excepted).
MemSQL’s performance claims include:
- Read performance 10% or so worse than memcached.
- Write performance 20% or so better than memcached.
- 1.2 million inserts/second on a 64-core, 1/2 TB of RAM machine.
- Similarly, 1/2 billion records loaded in under 20 minutes.
MemSQL company basics include: Read more
|Categories: Database compression, In-memory DBMS, Investment research and trading, Market share and customer counts, memcached, MemSQL, OLTP, Pricing, Web analytics||3 Comments|
SAP HANA has gotten much attention, mainly for its potential. I finally got briefed on HANA a few weeks ago. While we didn’t have time for all that much detail, it still might be interesting to talk about where SAP HANA stands today.
SAP HANA is positioned as an “appliance”. So far as I can tell, that really means it’s a software product for which there are a variety of emphatically-recommended hardware configurations — Intel-only, from what right now are eight usual-suspect hardware partners. Anyhow, the core of SAP HANA is an in-memory DBMS. Particulars include:
- Mainly, HANA is an in-memory columnar DBMS, based on SAP’s confusingly-renamed BI Accelerator/BW Accelerator. Analytics and most OLTP (OnLine Transaction Processing) go against the columnar part of HANA.
- The HANA DBMS also has an in-memory row storage option, used to store metadata, small tables, and so on.
- SAP HANA talks both SQL and MDX.
- The HANA DBMS is shared-nothing across blades or rack servers. I imagine that within an individual blade it’s shared everything. The usual-suspect data distribution or partitioning strategies are available — hash, range, round-robin.
- SAP HANA has what sounds like a natural disk-based persistence strategy — logs, snapshots, and so on. SAP says that this is synchronous enough to give ACID compliance. For some hardware partners, those “disks” are actually Fusion I/O cards.
- HANA is fault-tolerant “across servers”.
- Text support is “coming soon”, which makes sense, given that BI Accelerator was based on the TREX search engine in the first place. Inxight is also in the HANA text mix.
- You can put data into SAP HANA in a variety of obvious ways:
- Writing it directly.
- Trigger-based replication (perhaps from the DBMS that runs your SAP apps).
- Log-based replication (based on Sybase Replication Server).
- SAP Business Objects’ ETL tool.
SAP says that the row-store part is based both on P*Time, an acquisition from Korea some time ago, and also on SAP’s own MaxDB. The IBM white paper mentions only the MaxDB aspect. (Edit: Actually, see the comment thread below.) Based on a variety of clues, I conjecture that this was an aspect of SAP HANA development that did not go entirely smoothly.
Other SAP HANA components include: Read more
According to the MySQL Cluster home page, today’s MySQL Cluster release has — give or take terminology details – added transparent sharding (Edit: Actually, please see the first comment below) and a memcached interface. My quick comments on all this to a reporter a couple of days ago were:
- Persistent memcached is a useful thing. Couchbase’s sales illustrate that point: http://www.dbms2.com/2012/02/01/couchbase-update/
- MySQL has always given good performance when used just as a key-value store, e.g. http://www.dbms2.com/2010/08/22/workday-technology-stack/ . So it’s reasonable to hope the memcached interface will have good performance out of the box.
- MySQL’s clustering capabilities have long been weak, providing a window of opportunity for companies and products such as Schooner Information and dbShards. The gold standard for clustering is:
- Efficient transparent sharding: http://www.dbms2.com/2011/02/24/transparent-sharding/
- Synchronous replication at much better than two-phase-commit speeds. http://www.dbms2.com/2011/10/23/schooner-pivots-further/
I don’t really know enough about MySQL Cluster right now to comment in more detail.
There’s a perception that, if you want (relatively) worry-free database scale-out, you need a non-relational/NoSQL strategy. That perception is false. In the analytic case it’s completely ridiculous, as has been demonstrated by Teradata, Vertica, Netezza, and various other MPP (Massively Parallel Processing) analytic DBMS vendors. And now it’s false for short-request/OLTP (OnLine Transaction Processing) use cases as well.
My favorite relational OLTP scale-out choice these days is the SchoonerSQL/dbShards partnership. Schooner Information Technology (SchoonerSQL) and Code Futures (dbShards) are young, small companies, but I’m not too concerned about that, because the APIs they want you to write to are just MySQL’s. The main scenarios in which I can see them failing are ones in which they are competitively leapfrogged, either by other small competitors – e.g. ScaleBase, Akiban, TokuDB, or ScaleDB — or by Oracle/MySQL itself. While that could suck for my clients Schooner and Code Futures, it would still provide users relying on MySQL scale-out with one or more good product alternatives.
Relying on non-MySQL NewSQL startups, by way of contrast, would leave me somewhat more concerned. (However, if their code is open sourced. you have at least some vendor-failure protection.) And big-vendor scale-out offerings, such as Oracle RAC or DB2 pureScale, may be more complex to deploy and administer than the MySQL and NewSQL alternatives.
|Categories: Clustering, dbShards and CodeFutures, IBM and DB2, MySQL, NewSQL, NoSQL, OLTP, Open source, Oracle, Parallelization, Schooner Information Technology, Transparent sharding||2 Comments|
Schooner Information Technology started out as a complete-system MySQL appliance vendor. Then Schooner went software-only, but continued to brag about great performance in configurations with solid-state drives. Now Schooner has pivoted further, and is emphasizing high availability, clustered performance, and other hardware-agnostic OLTP (OnLine Transaction Processing) features. Fortunately, Schooner has some interesting stuff in those areas to talk about.
The short form of the SchoonerSQL (as Schooner’s product is now called) story goes roughly like this:
- SchoonerSQL replicates data — synchronously if the replication target is local, asynchronously if it is remote.
- Local synchronous replication provides high availability; remote asynchronous replication provides disaster recovery.
- SchoonerSQL’s local synchronous replication also provides read scale-out.
- Schooner has a partnership with Code Futures/dbShards to provide write scale-out via transparent sharding.
- SchoonerSQL has some secret sauce in replication performance. This has the effect of significantly increasing write performance (assuming you were going to replicate anyway), because otherwise you might have to slow down the master server’s write performance so that the slaves can keep up with it.
- Schooner believes it still has some single-server performance advantages as well.
|Categories: Clustering, dbShards and CodeFutures, MySQL, OLTP, Oracle, Parallelization, Schooner Information Technology||3 Comments|
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|