romseygeek commented on code in PR #16756: URL: https://github.com/apache/lucene/pull/16756#discussion_r4207180976
########## lucene/MIGRATE.md: ########## @@ -126,14 +139,36 @@ Enhanced error messages will clearly indicate: This parameter has no replacement, TieredMergePolicy no longer bounds the number of segments that may be merged together. -### Snowball dependency upgrade (Dutch stemmer) +### Snowball dependency upgrade (GITHUB#15505) + +Lucene 11 upgrades the bundled Snowball stemmers +([GITHUB#15505](https://github.com/apache/lucene/pull/15505)). Several +algorithms emit different stems than Lucene 10 (English, French, German, +Dutch, and others). Existing indexes that used Snowball stemming should +be reindexed so search-time analysis matches indexed tokens. -Snowball replaced the "Dutch" stemmer by the "Kraaij-Pohlmann" stemmer (previous called dutch-kp). As a result Lucene supports 2 Dutch stemmers: +#### Dutch stemmer -- DutchStemmer, which is now the "Kraaij-Pohlmann" stemmer. -- Dutch_porterStemmer, which is the DutchStemmer from Lucene-10 and before. +Snowball replaced the "Dutch" stemmer with the "Kraaij-Pohlmann" stemmer +(previously called dutch-kp). Lucene now ships two Dutch stemmers: -Opening an pre Lucene-11 index which is indexed using the DutchStemmer will succeed, but due to the different stemmer implementation a re-index is needed in order to make searching work correctly. Or replace DutchStemmer by Dutch_porterStemmer in your code. +- `DutchStemmer`, which is now the Kraaij-Pohlmann stemmer. + `DutchAnalyzer` and `language="Dutch"` use this. +- `Dutch_porterStemmer`, which is the Dutch stemmer from Lucene 10 and + earlier. + +A pre-Lucene-11 index that used `DutchStemmer` can still be opened, but +search will not match until you reindex, or switch the analyzer to Review Comment: ```suggestion search will not match until you reindex, or switch the query analyzer to ``` ########## lucene/MIGRATE.md: ########## @@ -101,9 +114,9 @@ Starting with Lucene 11.0.0, the index upgrade policy has been relaxed to allow #### Upgrade Example ```java -// Opening an index created with Lucene 10.x in Lucene 11.x+ +// Opening a 10.x index in 11 still works (MIN_SUPPORTED_MAJOR is 10). Review Comment: I guess we will update this once #16741 is merged? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
