Great news: Lucene 9.4 (optionally) uses mapped MemorySegments when JDK 19 is detected

[Uwe Schindler]

Hi Maurizio,

of course. We'll also ask people in the release notes to report slowdown 
or other issues. At moment, we do not know how much the special VM logic 
(safepoint!?) on closing a shared memory scope affects performance if 
used often (many indexes with high refresh rates in Elasticsearch).

Thanks for the support! Of course we are hoping that latest Java 21 will 
be the release where it goes enabled by default and stable API. If it 
would be in 20, even better. But I know there are still some ongoing 
refactorings.

Uwe

Am 29.09.2022 um 18:48 schrieb Maurizio Cimadamore:
> That is great and exciting news! Thanks for all your hard work keeping 
> up with the API changes.
>
> Of course it would be great to hear how it works for you guys, so, 
> should there be any odd performance issues, please give us a shout :-)
>
> Cheers
> Maurizio
>
>
>
> On 29/09/2022 16:46, Uwe Schindler wrote:
>> Hi all, hi Maurizio,
>>
>> I just wanted to inform you that after Java 19 was released we jumped 
>> on the train and we will most likely release Apache Lucene 9.4 
>> already tomorrow with support for project Panama. Users can run 
>> Lucene-based applications with "--enable-preview" and all should work 
>> automatically thanks to MR-JAR.
>>
>> The PR was merged on Monday after Eclipse Adoptium made the JDK 19 
>> builds available, so Gradle was able to pick them up to compile the 
>> MR-JAR part against it without having the Lucene developer to install 
>> JDK 19 in addition to Java 11/17. You can see the Panama code and 
>> also the Gradle setup and classloading tricks at runtime (that 
>> create/support the MR-JAR) here: 
>> https://urldefense.com/v3/__https://github.com/apache/lucene/pull/912__;!!ACWV5N9M2RV99hQ!OEiAAKic8OeN0Sr4AsSAc5eshUkCuUj970Q9VyCwWGGUDCu1tGUp_mCuUZIHATdDbFTVAmpy_2bSjFrhN-l_q2zKI0iI$ 
>>
>> I also opened issues in Elasticsearch ad Opensearch, so users can 
>> test it and report slowness/bugs earlier: 
>> https://urldefense.com/v3/__https://github.com/elastic/elasticsearch/issues/90526__;!!ACWV5N9M2RV99hQ!OEiAAKic8OeN0Sr4AsSAc5eshUkCuUj970Q9VyCwWGGUDCu1tGUp_mCuUZIHATdDbFTVAmpy_2bSjFrhN-l_q4kTHR8k$ 
>> , 
>> https://urldefense.com/v3/__https://github.com/opensearch-project/OpenSearch/issues/4637__;!!ACWV5N9M2RV99hQ!OEiAAKic8OeN0Sr4AsSAc5eshUkCuUj970Q9VyCwWGGUDCu1tGUp_mCuUZIHATdDbFTVAmpy_2bSjFrhN-l_qx7bA-BE$ 
>>
>> Uwe
>>
-- 
Uwe Schindler
uschindler at apache.org
ASF Member, Member of PMC and Committer of Apache Lucene and Apache Solr
Bremen, Germany
https://lucene.apache.org/
https://solr.apache.org/