CODEWITHSUNDEEP
couchbasecouchbase-lite
Cam
Cam

Reputation: 285

CBLite (couchbase lite) iOS platform

I’m pretty new with CBLite, I inherited a code that heavily uses FTS and all looked good until we discovered if we search for some words containing dash - like A-Something the query execution takes 4-5 times longer than usual. I couldn’t figure out why this happens and how I could find a solution on my end (mobile CBLite for the iOS platform).

Also, the search for some words that contain parenthesis (, won't work at all, the result is always empty for those items.

Upvotes: 1

Views: 71

Answers (1)

G. Blake Meike
G. Blake Meike

Reputation: 6715

Jens Alfke, an architect at Couchbase, says:

It’s been some years since I last worked on the FTS code in CBL but here are some things that might help:

  • I don’t think the tokenizer (the thing that breaks strings into words) considers a “-” part of a word. So “foo-bar” would be indexed as the two words “foo” and “bar”, and a search for “foo-bar” would just be looking for those two words. I could be wrong though; you could so some experiments to make sure.

  • If the above is true, then “A-Something” would be tokenized as “A” and “Something”, and “A” would be ignored when indexing because it’s a “stop-word”, one of the super common words like “the” and “he” that get tossed out. That means the query would be searching for just “Something”.

  • Parentheses are definitely not considered part of a word. So parens in a document string are ignored. Parens in a query will perform grouping of logical expressions as described in the SQLite FTS query language docs 1.

Upvotes: 0

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