Tag: Information Retrieval

EMC World 2010: Next-generation Search: Documentum Search Services

Presented by Aamir Farooq

Verity: Largest ingex 1 M Docs

FAST: Largest Index 200 M Docs

Challenging requirements today that all requires tradeoffs. Instead of trying to plugin third party search engines chose to build and integrated search engine for content and case management.

Flexible Scalability being promoted.

Tens to Hundreds of Millions of objects per host

Routing of indexing streams to different collections can be made.

Two instances can be up and running in less than 20 min!

Online backup restore is possible using DSS instead of just offline for FAST

FAST only supported Active/Active HA. In DSS more options:

Active/Passive

Native security. Replicates ACL and Groups to DSS

All fulltext queries leverage native security

Efficient deep facet computation within DSS with security enforcement. Security in facets is vital.

Enables effective searches on large result sets (underpriveleged users not allowed to see most hits in result set)

Without DSS, facets computed over only first 150 results pulled into client apps

100x more with DSS

All metrics for all queries is saved and can be used in analytics. Run reports in the admin UI.

DSS Feature Comparison

DSS supports 150 formats (500 versions)

The only thing lacking now is Thesaurus (coming in v 1.2)

Native 64-bit support for Linux and Windows, Core DSS is 64-bit)

Virtutalisation support on VMWare

Fulltext Roadmap

DSS 1.0 GA compatible with D 6.5 SP2 or later. Integration with CS 1.1 for facets, native security and XQuery)

Documentum FAST is in maintenance mode.

D6.5 SP3, 6.6 and 6.7 will be the last release that support FAST

From 2011 DSS will be the search solution for Documentum.

Index Agent Improvements

Guides you through reindexing or simply processing new indexing events.

Failure thresholds. Configure how many error message you allow.

One Box Search: As you add more terms it is doing OR instead of AND between each terms

Wildcards are not allowed OOTB. It can be changed.

Recommendations for upgrade/migration

  • Commit to Migrate
  • No additional license costs – included in Content Server
  • Identity and Mitigate Risks
  • 6.5 SP2 or later supported
  • No change to DQL – Xquery available.
  • Points out that both xDb and Lucene are very mature projects
  • Plan and analyze your HA and DR requirements

Straight migration. Build indices while FAST is running. Switch from FAST to DSS when indexing is done. Does not require multiple Content Servers.

Formal Benchmarks

  • Over 30 M documents spread over 6 nodes
  • Single node with 17 million documents (over 300 Gb index size)
  • Performance: 6 M Documents in FAST took two weeks. 30 M with DSS also took 2 weeks but with a lot of stops.
  • Around 42% faster for ingest for a single node compared to FAST

The idea is to use xProc to do extra processing of the content as it comes into DSS.

Conclusion

This is a very welcome improvement for one of the few weak points in the Documentum platform. We were selected to be part of the beta program so I would now have loved to tell you how great of an improvement it really is. However, we were forced to focus on other things in our SOA-project first. Hopefully I will come back in a few weeks or so and tell you how great the beta is. We have an external Enterprise Search solution powered by Apache Solr and I often get the question if DSS will make that unnecessary. For the near future I think it will not and that is because the search experience is also about the GUI. We believe in multiple interfaces targeted at different business needs and roles and our own Solr GUI has been configured to meet our needs based from a browse and search perspective. From a Documentum perspective the only client today that will leverage the faceted navigation is Centerstage and that is focused on asynchronous collaboration and is a key component in our thinking as well, but for different purposes. Also even though DSS is based on two mature products (as I experienced at Lucene Eurocon this week) I think the capabilities to tweak and monitor the search experience at least initially will be much better in our external Solr than using the new DSS Admin Tool although it seems like a great improvement form what the FAST solution offers today.

Another interesting development will be how the xDB inside DSS will related to the “internal” XML Store in terms of integration. Initially they will be two servers but maybe in the future you can start doing things with them together. Especially if next-gen Documentum will replace the RDBMS as Victor Spivak mentioned as a way forward.

At the end having a fast search experience in Documentum from now is so important!

Further reading

Be sure to also read the good summary from Technology Services Group and Blue Fish Development Group about their take on DSS.

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