Activate Synonyms in an IDOL Server
This solution is the easiest of the three synonym choices to implement, but is useful only if you require synonym matching for a maximum of approximately 100 terms. Beyond this limit, query response times experience a growing increase with the number of synonym terms, and it can have a negative impact on indexing performance.
Internal synonyms introduce the concept of expansion level; that is, the conceptual distance between synonyms. A synonym that you specify explicitly has an expansion level of zero. You can then expand the synonyms again, to get further expansions. For example, if there is a hierarchy of synonyms such that terrier expands to dog, and dog expands to animal, then:
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terrier to dog has an expansion level of zero.
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dog to animal also has an expansion level of zero.
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terrier to animal has an expansion level of one.
Configuration
To use synonyms in an IDOL Server, you must configure the [Synonym]
section in the IDOL or Content server configuration file. In this section, you configure a list of synonym jobs, which are run at query time.
Each synonym job defines a file, which has a list of synonyms to process, and the MaxExpandLevel
. For example:
[Synonym] 0=PC_Syn [PC_Syn] File=myfile.txt MaxExpandLevel=1
The referenced file must contain comma-separated lists of synonymous terms and phrases for a particular language type. For example, myfile.txt
might contain synonyms for animals:
[EnglishUTF8] dog,canine,puppy,hound,wolf cat,feline,kitten,kitty
You must also apply the SynonymType
field property to any fields that you want to perform synonym expansion on. For example:
[FieldProcessing] ... 19=SynonymMatch // Specify the fields that synonym expansion will be performed on [SynonymMatch] Property=ApplySynonymMatch PropertyFieldCSVs=*/DRETITLE,*/DRECONTENT // Specify the synonym job to apply to those fields [ApplySynonymMatch] SynonymType=PC_Syn
Usage
After synonyms have been activated, you can use them by setting the Synonym
action parameter to True
in the Query
action.