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Uwe Schindler commented on LUCENE-7966: --------------------------------------- [~dweiss]: The patched class files are actually easier to maintain, as we do not need Java 9 to compile, no duplicate class files in source folder, or some fake Java 9 signature files (with questionable license) on bootclasspath (see my previous branch). This was the main reason to rewrite the class files instead of maintaining multiple source files. It's just a nice side-effect to no longer need the delegation methods. So I perosnally like the approach much more. It would be horrible if we'd require all committers to have both Java 8 and Java 9 installed! The question here was just for confirmation and comparison of both approaches, if they have some side effects. bq. The slowdown on pic (the most compressible file) is reproducible [~jpountz]: The one with biggest slowdown on Java 8 is the one with biggest speedup in Java 9. The reason is quite clear: The Java 8 implementation by Robert does more checks than the "old" LZ4 implementation (for safety and to be compatible with new Java 9 impl). But on Java 9 the new method used is an intrinsic, so we have a huge perf win! > build mr-jar and use some java 9 methods if available > ----------------------------------------------------- > > Key: LUCENE-7966 > URL: https://issues.apache.org/jira/browse/LUCENE-7966 > Project: Lucene - Core > Issue Type: Improvement > Components: core/other, general/build > Reporter: Robert Muir > Labels: Java9 > Attachments: LUCENE-7966.patch, LUCENE-7966.patch, LUCENE-7966.patch, > LUCENE-7966.patch, LUCENE-7966.patch > > > See background: http://openjdk.java.net/jeps/238 > It would be nice to use some of the newer array methods and range checking > methods in java 9 for example, without waiting for lucene 10 or something. If > we build an MR-jar, we can start migrating our code to use java 9 methods > right now, it will use optimized methods from java 9 when thats available, > otherwise fall back to java 8 code. > This patch adds: > {code} > Objects.checkIndex(int,int) > Objects.checkFromToIndex(int,int,int) > Objects.checkFromIndexSize(int,int,int) > Arrays.mismatch(byte[],int,int,byte[],int,int) > Arrays.compareUnsigned(byte[],int,int,byte[],int,int) > Arrays.equal(byte[],int,int,byte[],int,int) > // did not add char/int/long/short/etc but of course its possible if needed > {code} > It sets these up in {{org.apache.lucene.future}} as 1-1 mappings to java > methods. This way, we can simply directly replace call sites with java 9 > methods when java 9 is a minimum. Simple 1-1 mappings mean also that we only > have to worry about testing that our java 8 fallback methods work. > I found that many of the current byte array methods today are willy-nilly and > very lenient for example, passing invalid offsets at times and relying on > compare methods not throwing exceptions, etc. I fixed all the instances in > core/codecs but have not looked at the problems with AnalyzingSuggester. Also > SimpleText still uses a silly method in ArrayUtil in similar crazy way, have > not removed that one yet. -- This message was sent by Atlassian JIRA (v6.4.14#64029) --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org For additional commands, e-mail: dev-h...@lucene.apache.org