Tomoko is correct, an MR JAR is created not only upon release but also every time you create a lucene-core JAR on branch_8x.
On Sun, Aug 30, 2020 at 5:49 AM Tomoko Uchida <tomoko.uchida.1...@gmail.com> wrote: > I believe mr-jar build is enabled in the 8x branch (LUCENE-7966), and the > workaround was dropped on the master branch when the minimum java version > was bumped up to java 11 (LUCENE-8738); if my understanding is correct. > > $ jar tf core/lucene-core-8.6.1.jar | grep META-INF/versions > META-INF/versions/ > META-INF/versions/9/ > META-INF/versions/9/org/ > META-INF/versions/9/org/apache/ > ... > > $ jar tf core/build/libs/lucene-core-9.0.0-SNAPSHOT.jar | grep > META-INF/versions > // no outputs > > > > > 2020年8月30日(日) 6:48 Mike Drob <md...@apache.org>: > >> Do you know if these mr-jars are built by default as part of the release >> process? I definitely had no idea about them when doing 8.5.2 and did not >> even think to verify anything about it. >> >> On Sat, Aug 29, 2020 at 4:05 PM Adrien Grand <jpou...@gmail.com> wrote: >> >>> It may only be indirectly related to your question, but there is support >>> for vectorized operations of byte[] arrays that was added in JDK 13 (this >>> blog https://richardstartin.github.io/posts/vectorised-byte-operations >>> explains >>> well what it is about) that we started leveraging for compressing terms >>> dictionaries in Lucene 8.5: >>> https://issues.apache.org/jira/browse/LUCENE-4702. >>> >>> I don't know how well this is known but our build also has logic to >>> create multi-release JARs. We don't use it in master today but it's used on >>> branch_8x, which requires Java 8, in order to use APIs that were introduced >>> in Java 9 such as Arrays#mismatch. See the "patch-mr-jar" target in the >>> branch_8x build: >>> https://github.com/apache/lucene-solr/blob/branch_8x/lucene/common-build.xml#L602. >>> So if APIs that could help performance were introduced in say JDK 15, we >>> might still be able to leverage them in Lucene/Solr 9 using the same >>> mechanism. >>> >>> >>> >>> On Tue, Aug 11, 2020 at 1:12 AM Marcus Eagan <marcusea...@gmail.com> >>> wrote: >>> >>>> In my IDE, I have a few profiling tools that I bounce between that I >>>> started using in my work at Lucidworks but I continue to use in my current >>>> work today. I have suspicions that there may be some performance >>>> improvements in Java 11 that we can exploit further. I'm curious as to if >>>> there has been any investigation, possibly Mark Miller or >>>> @u...@thetaphi.de <u...@thetaphi.de>, into performance improvements >>>> specific to the newer version of Java in Master? There are some obvious >>>> ones that we get for free, like a better GC, but curious as to prior work >>>> in this area before publishing anything that might be redundant or >>>> irrelevant. >>>> >>>> Best, >>>> >>>> -- >>>> Marcus Eagan >>>> >>>> >>>> >>>> >>> >>> -- >>> Adrien >>> >>> >>> -- Adrien
