MARKLOGIC SERVER

You can watch as the server does the scoring math if you use the Admin Interface to
turn on the diagnostic flag "relevance", which dumps the math to the server error
log file. For programmatic access, you can pass "relevance-trace" as an option to
cts:search() and use cts:relevance-info() to extract an XML-formatted trace
log. Tracing has a performance impact, so it's not recommended for production.
STOP WORDS
A stop word is a word that is so common and with so little meaning by itself that it can
be ignored for purposes of search indexing. MarkLogic does not require or use stop
words. This means it's possible to search for phrases such as "to be or not to be" which
consist solely of stop words, or phrases like "Vitamin A" where one of the words is a
stop word.
However, MarkLogic does limit how large the positions list can be for any particular
term. A positions list tracks the locations in documents where the term appears
and supports proximity queries and long phrase resolution. The maximum size is a
configurable database setting called positions list max size and is usually several hundred
megabytes. Once a term has appeared so many times that its positions list exceeds
this limit, the positional data for that term is removed and no longer used in query
resolution (because it would be too inefficient to do so). You can detect whether any
terms have exceeded this limit by looking for a file named StopKeySet having nonzero
length in one of the on-disk stands.
FIELDS
MarkLogic allows administrators to turn on and off various indexes. The list of indexes
is long: stemmed searches, word searches, fast phrase searches, fast case-sensitive
searches, fast diacritic-sensitive searches, fast element word searches, element word
positions, fast element phrase searches, trailing wildcard searches, trailing wildcard
word positions, three-character searches, three-character word positions, two-character
searches, and one-character searches. Each index improves performance for certain
types of queries at the expense of increased disk consumption and longer load times.
In some situations, it makes sense to enable certain indexes for parts of documents but
not for other parts. For example, the wildcard indexes may make sense (i.e., justify their
overhead) for titles, authors, and abstracts but not for the longer full body text.
Fields let you define different index settings for different subsets of your documents.
Each field gets a unique name, a list of elements or attributes to include, and another
list to exclude. For example, you can include titles, authors, and abstracts in a field but
exclude any footnotes within the abstract. Or, maybe you want to include all document
content in a field but remove just elements from the field's index.
That's possible, too. At request time, you use field-aware functions like cts:fieldword-query()
to express a query constraint against a field.
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