I want to upgrade my Alfresco server to 5.2 and in all my custom webscripts am using lucene queries. Since from Alfresco 5.x lucene indexing has been removed and solr indexing is not instantaneous, am planing to use fts_alfresco search. While testing i found that few lucene queries can be used for fts_alfresco search without modifying. So my concern is will i be able to do fts_alfresco search using lucene query? If no, is there any better way to migrate all my lucene queries to fts_alfresco?
Thanks in advance.
You will need to test/check your queries since there are small differences (for instance, date range query is not the same), but in general there's no reason why you would not be able to use FTS.
I'm not sure a comprehensive documentation exists where you would see all those small differences, though. If you find it, please share.
"Alfresco FTS is compatible with most, if not all of the examples here.."
https://community.alfresco.com/docs/DOC-4673-search
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I am using grails searchable plugin. It creates index files on a given location. Is there any way in searchable plugin to create Lucene index in a database?
Generally, no.
You can probably attempt to implement your own format but this would require a lot of effort.
I am no expert in Lucene, but I know that it is optimized to offer fast search over the filesystem. So it would be theoretically possible to build a Lucene index over the database, but the main feature of lucene (being a VERY fast search engine) would be lost.
As a point of interest, Compass supported storage of a Lucene index in a database, using a JdbcDirectory. This was, as far as I can figure, just a bad idea.
Compass, by the way, is now defunct, having been replaced by ElasticSearch.
We have indexed our documents with Lucene 2.3.1 and now want to move to Lucene 3.0.3 for better features. I want to know whether the index will work as is and will I be able to add more documents, with 3.0.3, to the existing index without any hassles or do I have to re-index the whole thing.
Thanks a lot in advance.
I am quite sure that the indexes will be incompatible with Lucene 3 if they were built under Lucene 2 (in fact I'm 99% positive of this).
However, you may be able to convert them rather than rebuild them. Have a look here for some high-level guidance in this area.
I've got an ASP.NET site backed with a SQL Server database. I'm been using Lucene.NET to index and search the database. I'm adding faceted search navigation to the results page (the facets are a hiarchical category tree). I asked yesterday to make sure I was using the right technique for faceting. All I've gotten so far is a suggestion to use Solr, but Solr does a lot of things I don't need.
I would really like to know from anyone who is familiar with the Solr's source code if Solr's facet processing is terribly different from the one described here by Bert Willems. Bascially you have a Lucene filter for each facet, you get the bits array from it, and you count the set bits in the array.
I'm thinking since mine is hiarchical to begin with I should be able to optimize this pretty well, but I'm afraid I might be grossly under-estimating the impact of this design on search performance. If Solr is no quicker, I'm not going to gain anything by using it.
I'd recommend creating a prototype project modeling your faceting needs with Solr and benchmark it against Lucene.net.
Even though faceting in Solr is very optimized (and gets new optimizations all the time, like the parallel per-segment faceting method), when using Solr there is some overhead, for example network roundtrips and response parsing.
If your code already implements Lucene.NET, performs adequately and you don't need any of Solr's additional features, then there is no need to switch to Solr. But also consider that if you choose Solr you will get faceting performance boosts for free with each new version.
-- I don't want to start any religious wars, but a quick google search indicates that Apache Lucene is the preferred open source tool for indexing and searching. Are there others?
-- What file format does Lucene use to store its index file(s)?
Thank is advance.
Doug
Which are the best alternatives to Lucene? And as a lucene user I can say it has improved a lot performance wise the last couple of versions (NOT meaning it was slow before!)
it uses an proprietary format see here
I suggest you to look at Sphinx.
I have an experience with Lucene.net and we have many problems with multithread indexing. Lucene stores index in files, and this files can be locked by anti-viruses software.
Also you can not compare numbers in Lucene: it is impossible to filter products by size and price.
I'm looking into using Lucene and/or Solr to provide search in an RDBMS-powered web application. Unfortunately for me, all the documentation I've skimmed deals with how to get the data out of the index; I'm more concerned with how to build a useful index. Are there any "best practices" for doing this?
Will multiple applications be writing to the database? If so, it's a bit tricky; you have to have some mechanism to identify new records to feed to the Lucene indexer.
Another point to consider is do you want one index that covers all of your tables, or one index per table. In general, I recommend one index, with a field in that index to indicate which table the record came from.
Hibernate has support for full text search, if you want to search persistent objects rather than unstructured documents.
There's an OpenSymphony project called Compass of which you should be aware. I have stayed away from it myself, primarily because it seems to be way more complicated than search needs to be. Also, as I can tell from the documentation (I confess I haven't found the time necessary to read it all), it stores Lucene segments as blobs in the database. If you're familiar with the Lucene architecture, Compass implements a Lucene Directory on top of the database. I think this is the wrong approach. I would leverage the database's built-in support for indexing and implement a Lucene IndexReader instead. The same criticism applies to distributed cache implementations, etc.
I haven't explored this at all, but take a look at LuSql.
Using Solr would be straightforward as well but there'll be some DRY-violations with the Solr schema.xml and your actual database schema. (FYI, Solr does support wildcards, though.)
We are rolling out our first application that uses Solr tonight. With Solr 1.3, they've included the DataImportHandler that allows you to specify your database tables (they call them entities) along with their relationships. Once defined, a simple HTTP request will tirgger an import of your data.
Take a look at the Solr wiki page for DataImportHandler for details.
As introduction:
Brian McCallister wrote a nice blog post: Using Lucene with OJB.