Oh I see, it is "index.properties". This is not a Lucene file. I think
when opening that file it should pass READ_ONCE as IOContext to get rid
of that issue.
Uwe
Am 19.02.2026 um 14:05 schrieb Uwe Schindler via dev:
Hi,
I think the problem here is that not all fixes around that use-case
were applied to Lucene 9. The problem here is that in Lucene 9 we do
not open all files in "read-once" mode, especially the segment infos
files. The error message about 78 bytes not beeing able to be mapped
looks really like the segment infos file, we don't have any other
files so small. This is no longer an issue in Lucene 10.
Uwe
Am 18.02.2026 um 17:40 schrieb David Smiley:
The same boolean setting was useful as a mitigation for the following
error, totally different business / search cluster -- Solr 9.10, Java
21,
did not happen with Java 17 with identical search cluster:
Caused by: java.io.IOException: Map failed:
MemorySegmentIndexInput(path="/var/solr/REDACTED_PATH/REDACTED_COLLECTION_shard39_replica_t77/data/index.properties")
[this may be caused by lack of enough unfragmented virtual address
space or
too restrictive virtual memory limits enforced by the operating system,
preventing us to map a chunk of 78 bytes. Please review 'ulimit -v',
'ulimit -m' (both should return 'unlimited'), and 'sysctl
vm.max_map_count'
Reminder: the setting doesn't exist in Solr 10; a proper solution
must be
found for a Solr 10 upgrade, assuming the problem re-appears. I'm
somewhat
optimistic a further Java upgrade (to say 25) would be helpful, albeit I
haven't investigated that yet.
On Wed, Aug 21, 2024 at 1:23 PM David Smiley <[email protected]> wrote:
For those trying Java 21 with Solr, if you find the performance to be
bad then try setting
-Dorg.apache.lucene.store.MMapDirectory.enableMemorySegments=false
This made a huge difference for me on our Solr nodes at work.
I filed the following ticket to Solr that ought to avoid the JDK
performance regression if done:
https://issues.apache.org/jira/browse/SOLR-17375
~ David Smiley
Apache Lucene/Solr Search Developer
http://www.linkedin.com/in/davidwsmiley
--
Uwe Schindler
Achterdiek 19, D-28357 Bremen
https://www.thetaphi.de
eMail: [email protected]
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