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reconcile changes txt

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ChrisHegarty 2024-08-23 15:04:41 +01:00
parent ad81402791
commit e850cd1c86
1 changed files with 8 additions and 2 deletions
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lucene/CHANGES.txt
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@ -351,8 +351,14 @@ Optimizations
Closing many individual index files can potentially lead to a degradation in execution performance.
Index files are mmapped one-to-one with the JDK's foreign shared Arena. The JVM deoptimizes the top
few frames of all threads when closing a shared Arena (see JDK-8335480). We mitigate this situation
by 1) using a confined Arena where appropriate, and 2) grouping files from the same segment to a
single shared Arena. (Chris Hegarty, Michael Gibney, Uwe Schindler)
when running with JDK 21 and greater, by 1) using a confined Arena where appropriate, and 2) grouping
files from the same segment to a single shared Arena.
A system property has been added that allows to control the total maximum number of mmapped files
that may be associated with a single shared Arena. For example, to set the max number of permits to
256, pass the following on the command line
-Dorg.apache.lucene.store.MMapDirectory.sharedArenaMaxPermits=256. Setting a value of 1 associates
a single file to a single shared arena.
(Chris Hegarty, Michael Gibney, Uwe Schindler)
* GITHUB#13585: Lucene912PostingsFormat, the new default postings format, now
only has 2 levels of skip data, which are inlined into postings instead of