[ https://issues.apache.org/jira/browse/LUCENE-8753?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16853870#comment-16853870 ]
David Smiley commented on LUCENE-8753: -------------------------------------- Are there any concerns of the Lucene project accepting this new PostingsFormat? Two PostingsFormats now. See my last comment please (RE AutomatonTermsEnum and DeltaBaseTermStateSerializer); I'm curious what others think. > New PostingFormat - UniformSplit > -------------------------------- > > Key: LUCENE-8753 > URL: https://issues.apache.org/jira/browse/LUCENE-8753 > Project: Lucene - Core > Issue Type: Improvement > Components: core/codecs > Affects Versions: 8.0 > Reporter: Bruno Roustant > Assignee: David Smiley > Priority: Major > Attachments: Uniform Split Technique.pdf, luceneutil.benchmark.txt > > Time Spent: 20m > Remaining Estimate: 0h > > This is a proposal to add a new PostingsFormat called "UniformSplit" with 4 > objectives: > - Clear design and simple code. > - Easily extensible, for both the logic and the index format. > - Light memory usage with a very compact FST. > - Focus on efficient TermQuery, PhraseQuery and PrefixQuery performance. > (the pdf attached explains visually the technique in more details) > The principle is to split the list of terms into blocks and use a FST to > access the block, but not as a prefix trie, rather with a seek-floor pattern. > For the selection of the blocks, there is a target average block size (number > of terms), with an allowed delta variation (10%) to compare the terms and > select the one with the minimal distinguishing prefix. > There are also several optimizations inside the block to make it more > compact and speed up the loading/scanning. > The performance obtained is interesting with the luceneutil benchmark, > comparing UniformSplit with BlockTree. Find it in the first comment and also > attached for better formatting. > Although the precise percentages vary between runs, three main points: > - TermQuery and PhraseQuery are improved. > - PrefixQuery and WildcardQuery are ok. > - Fuzzy queries are clearly less performant, because BlockTree is so > optimized for them. > Compared to BlockTree, FST size is reduced by 15%, and segment writing time > is reduced by 20%. So this PostingsFormat scales to lots of docs, as > BlockTree. > This initial version passes all Lucene tests. Use “ant test > -Dtests.codec=UniformSplitTesting” to test with this PostingsFormat. > Subjectively, we think we have fulfilled our goal of code simplicity. And we > have already exercised this PostingsFormat extensibility to create a > different flavor for our own use-case. > Contributors: Juan Camilo Rodriguez Duran, Bruno Roustant, David Smiley -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org For additional commands, e-mail: dev-h...@lucene.apache.org