Archive for April, 2012

An open source replacement for the dtSearch closed source search engine

We’ve been working on a client project where we needed to replace the dtSearch closed source search engine, which doesn’t perform that well at scale in this case. As the client has significant investment in stored queries (it’s for a monitoring application) they were keen that the new engine spoke exactly the same query language as the old – so we’ve built a version of Apache Lucene to replace dtSearch. There are a few other modifications we had to do as well, to return such things as positional information from deep within the Lucene code (this is particularly important in monitoring as you want to show clients where the keywords they were interested in appeared in an article – they may be checking their media coverage in detail, and position on the page is important).

First, we developed a new Lucene Analyzer that speaks the same syntax as dtSearch, allowing us to index text input. On the search side we have a Lucene QueryParser that shares this syntax. To make it easier to use we’ve wrapped the whole lot in a modified Solr server. As we needed some features of very recent Lucene code, our modifications are based on a patch to Lucene trunk (and so the source code isn’t for the faint hearted – if you need it let us know, but we’re not currently providing it for download).

We’re not sure if there’s anyone else out there who needs an open source alternative to dtSearch – but in case there is we’ve provided a downloadable WAR file with the latest Solr executables in our downloads area, including a brief README file.

More generally, what this project demonstrates is that even if you have significant investment in your existing search infrastructure it is entirely possible to move to an open source alternative, which may be faster and will almost certainly be more economically scalable. Does anyone else have a search engine they’d like to replace?

Amazon CloudSearch – a game changer?

Amazon have just launched a cloud-based search service, which promises a ‘fully managed search service in the cloud’ – and it certainly looks impressive, with auto-scaling built in. You simply create a service, upload documents as JSON or XML and then perform searches. For cases where you need to search publically available data this offers a great way to avoid having to install and integrate any search software – of course it won’t be so popular if you’re worried about where your data actually is, or other complications such as the Patriot Act.

As you might expect, some people are already offering services based around CloudSearch (we’d be happy to do the same - just ask!) and there’s a demo of searching Wikipedia available. I’m not sure who SmackBot is but I’m slightly wary of reading any Wikipedia articles it’s had something to do with…

Of course searching Wikipedia is nothing new and I sometimes wish for a different choice of source material for search demos.

One thing that seems clear is that with the rise of cloud-based search options (here’s another from our partners Lucid Imagination, based on Apache Lucene/Solr) the cost and complication of ’simple’ search projects could fall dramatically, applying further pressure to those companies selling closed source search engines for frankly unrealistic prices. Amazon’s offering, with their huge experience in cloud-based services, has the potential to be a game changer for the search market.

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Posted in News, Technical

April 12th, 2012

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