I'm somewhat proud to announce that current version of pgestraier now includes consistency triggers which will keep Hyper Estraier index up-to-date with data in your database.

That, coupled with ability to create full-text indexes easily, just by running helper script on database, makes pgestraier powerful solution if you need fast full-text indexing with ability to off-load search to another machine (thanks to Hyper Estraier P2P architecture) or need perfect N-gram search results.

This project might also help people who are porting applications which use MySQL full-text search to PostgreSQL (actually, it's it going to be used just for that).

Real trunk of development is in Subversion, and CVS repository at pgFoundry is just a mirror copy. Enjoy it, while I prepare to leave for seaside.

I needed this for a long time, so finally I wrote it. It's a birday present to... well... me. Geeks are strange, right?

Well, this was fast. In last post I promised to work some more on pgestraier and well, I did. It now supports node API, and generally I'm quote happy with it. It even has a proper home page.

I just added node API to HyperEstraier perl bindings. It's my first real project in C++, so be kind to it :-)
All changes are available at Subversion repository and if I didn't do something stupid it will be included in upstream version, I hope. Next step: add node API to pgestraier...

Search::Estraier will be perl API to Hyper Estraier. It's written using excellent Inline::C

Grand plan is to use pgestraier from PostgreSQL to query Estraier index and Search::Estraier to create index. This would allow to combine structured data in RDBMS with semi-structured data in full text index. Additional normalized tables can be created using materialized views in PostgreSQL, and if all goes well, it will be part of WebPAC version 2 which will be universal hybrid (structured/full text) storage.

Update: I had good luck to find already working perl bindings for Hyper Estraier at MATSUNO Tokuhiro blog. Thanks a lot! So, work on Search::Estraier is suspended.

Hyper Estraier, new version of previously mentioned Estraier has a very good API. So, I wrote pgestraier function for it. Now you can query Estraier indexes directly from PostgreSQL.

It's beta, yada, yada, if it breaks you get to keep both parts. However, it's extremely useful if you want to (left/outer) join index results with data in PostgreSQL.

.

I often got questions like: how should I make my search?. Answer to that questions is: It depends. This is a quick overview of few really good solutions to searching your data:

• swish-e
  
  Toolkit for building search engines. Supports meta data, properties
  (data which isn't indexed but just stored alongside index, gzip in this
  case), regular expressions and different input formats (both from [perl]
  scripts and from filesystem). It supports searching (but not indexing) from
  perl using SWISH::API.
  
  It doesn't support incremental indexing in
  current stable versions, but code does exists in CVS, but it isn't stable
  yet (for example index merge always segfaults for me using incremental
  indexing). Indexing from perl will hopefully be available when I
  
  finish perl module for it.
  
  If you want custom search engine, this is my first choice.
  
• Xapian and Omega
  
  Another great search engine with very good perl support (for both
  indexing and searching).
  
  Only drawback is that it doesn't support wild-cards (for valid reason,
  your stammer should do that work!), but if you need to update your indexes
  often, I would recommend it. It's a order of magnitude about three
  times slower in indexing and somewhat slower when searching than swish-e,
  but speed isn't everything!
  
  If I need custom engine for dynamically changing data, this is my choice.
  It comes with Omega search tools which can index files on disk and provide
  binary (C++) cgi for searching. I prefer to build my own.
  
• Estraier
  
  Very good search engine with clustering of results. Support wild-cards, but doesn't support any meta data (you can't search just titles).
  
  This is a valid alternative to href="http://desktop.google.com/">Google Desktop for Linux
  users.
  
• SWISH++
  Rewrite of swish-e in C++. Uses very clever heuristics to extracts just words from English language reducing index size and producing blazingly fast searches.
  
  However it's not well suited in indexing foreign languages or non-English
  words (e.g. dates or numbers). Doesn't have any support for perl out-of-the
  box, but at one point in time
  
  I wrote module for indexing and searching. However, without clever
  heuristics it's not faster than swish-e so I discontinued development of
  that module (but it is fully functional as-is).
  

So, answer isn't easy. But I hope that this quick overview will help someone.

Updated on 2005-01-06: Olly Betts contacted me about this post and provoked me to do benchmark of Xapian again. I was totally unfair, because new benchmark
doesn't confirm my claim that it's order of magnitude slower. I will
probably write separate post about this benchmark because it also compares
incremental and non-incremental version of swish-e.