hi all when use highlighter, We must provide a tokenStream and the original text. To get a tokenStream, we can either reanlyze the original text or use saved TermVector to reconstruct it. In my application, highlight will cost average 200ms-300ms, and I want to optimze it to lower than 100ms. So I decided to try TermVector.
The javadoc of public static TokenStream getTokenStream(TermPositionVector tpv, boolean tokenPositionsGuaranteedContiguous) is: Low level api. Returns a token stream or null if no offset info available in index. This can be used to feed the highlighter with a pre-parsed token stream In my tests the speeds to recreate 1000 token streams using this method are: - with TermVector offset only data stored - 420 milliseconds - with TermVector offset AND position data stored - 271 milliseconds (nb timings for TermVector with position data are based on a tokenizer with contiguous positions - no overlaps or gaps) The cost of not using TermPositionVector to store pre-parsed content and using an analyzer to re-parse the original content: - reanalyzing the original content - 980 milliseconds The re-analyze timings will typically vary depending on - 1) The complexity of the analyzer code (timings above were using a stemmer/lowercaser/stopword combo) 2) The number of other fields (Lucene reads ALL fields off the disk when accessing just one document field - can cost dear!) 3) Use of compression on field storage - could be faster due to compression (less disk IO) or slower (more CPU burn) depending on the content. Parameters: tpv tokenPositionsGuaranteedContiguous true if the token position numbers have no overlaps or gaps. If looking to eek out the last drops of performance, set to true. If in doubt, set to false. I have some questions 1. it says "reanalyze depending on The number of other fields" . but to highlight, we must provide original text, so we will read all the fields of the document. So no matter we use termvector reconstruction or reanalyzation, we both need to read all the field of a document. 2. to speed up, tokenPositionsGuaranteedContiguous can be set. which requires "contiguous positions - no overlaps or gaps". no overlaps is obvious, what's gaps mean? My analyzer just like public final boolean incrementToken() throws IOException { termAtt.setTermBuffer(context, beginIndex, length); termAtt.setTermLength(length); offsetAtt.setOffset(beginIndex, endIndex); return true; } can I set it to true? --------------------------------------------------------------------- To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org For additional commands, e-mail: java-user-h...@lucene.apache.org