Commuting on Bicycle Again

Bike Route from Concord To Macromedia in Newton While I still love coming to work at Macromedia every day, now that I'm biking to work a few times a week again the best part of the day is now the bike ride home. I started last October, but soon the first snows fell and I had to hang up the bike. This April the temperature is back into the 60's and the last snow is a couple weeks behind.

The first 3 miles of the 13 mile trip home is largely uphill, but then as the roads grow smaller as I wind my way into the suburbs the ride flattens out and I can enjoy the sights and smells along the way.

Just past the train tracks on rt. 117 in Lincoln, I pass the Audubon Society's Drumlin Farm where cattle are grazing by the roadside. I love the smell of cow manure in the evening. I'm just that way.

Continuing through Lincoln I reach Codman Farm and the community gardens, and there I change from the pedaling on the sliver of road they call a shoulder to a flowing, country walkway with some fun hills that twist and curve under apple trees and along side sheep and wide open farm fields.

The country path continues along rt 126 where the nearby vernal pools are filled to the brink not just with fresh water but with a chorus of spring peepers. If I time it just right, I pass Walden Pond (satellite) just as the sun sets at the opposite end just before it passes through the distant pine trees.

I don't think listening to podcasts is great idea for bike riding on the roadside, but its a great way to review the days events, and I even wrote this blog entry in my head on the way today, now all that's left is the typing.

J2EE Clustering with Tangosol's Coherence

Last night I attended the local Boston Java Meetup Group to get a sense of what my technology cousins are up to since most of my conversations are always in Macromedia-centric arenas.

The most interesting part of the evening for me was meeting Cameron Purdy. Cameron was obviously the Java guru at this table of Java gurus. It turns out that Cameron is president of Tangosol, a company in Somerville which he founded. Tangasol's flagship product Coherence is a type of J2EE clustering software which appropriate for storing extremely large quantities of data in memory and replicating it across large numbers of J2EE cluster members while handling thousands of data updates per second.

Coherence is described in various contexts as:

Tangosol Coherence enables in-memory data management for clustered J2EE applications and application servers. Coherence makes sharing and managing data in a cluster as simple as on a single server. It accomplishes this by coordinating updates to the data using cluster-wide concurrency control, replicating and distributing data modifications across the cluster using the highest performing clustered protocol available, and delivering notifications of data modifications to any servers that request them.


and

... provides scalable performance and is not compromised by single points of failure ... [and] manages many gigabytes of data and thousands of updates per second ... self partioning architecture without single points of failure or measureable GC pauses ...


That last quote is about as much as I could jot down while watching this presentation on Coherence while trying to keep up with Cameron's break-neck reading velocity. As an aside, this presentation was hauntingly similar to a Breeze presentation, but actually used a similar product from Articulate.

This large scale clustering software appears to be significantly more robust than the JINI-based clustering found in Macromedia JRun. Replication of session data across small JRun clusters is generally thought to have a noticible performance impact and its typically recommended to minimize the data that is replicated in this manner to unique keys that act as pointers to persistant data on the backend databases. A couple reviews of JRun clustering are available for comparison:

CFMX 7 Verity Error: com.verity.organize.WorkSpaceException

When creating collections in ColdFusion MX 7 via the Administrator or code, you might encounter the following error:

Unable to create collection {collection name}.
An error occurred while performing an operation in the Search Engine library.
Error opening the collection: com.verity.organize.WorkSpaceException: Path not found [VdkError_PathNotFound]. (-104)


The Verity collection directory tree contains a subdirectory called ws to act as a work space during collection creation. When that directory starts to accumulate directories and files, Verity may report this WorkSpaceException.

The work space directory on a "Server Configuration" installation would be
$CFHOMEverityDataservicesColdFusionK2_indexserver1ws
whereas if Verity was installed in J2EE configuration on WebSphere on Windows for example the Verity work space directory would be
{driveletter}ColdFusionSearchServiceDataservicesColdFusionK2_indexserver1ws
where the Verity bits were laid down in the ColdFusionSearchService directory as a sub-installation routine.

To resolve the exception and create Verity collections again, stop the ColdFusion MX 7 Search Service, remove all the contents of the ws/ directory, then start the Search Service.