Hi,
I think there are a few problems in your setup which you did not
explain. The suppression of the message seems to be an XY-problem. There
is no need to suppress the message if everything is setup correctly - as
it is displayed only once!
First of all: If you don't enable the vector incubator module on command
line, a WARNING is logged on startup of Java VM. It is not logged on
every request. If this is the case, you have far bigger problems! (see
below). If you don't enable the vector incubator, some requests may be
slower. The reason why it is logged is because on initialization of
Lucene some requests are done to the VecorUtils class which triggers the
one-time warning message. You can suppress it by adding a config file
for java.util.logging (see
https://docs.oracle.com/en/java/javase/21/core/java-logging-overview.html
on how to configure it).
If you enable the Java Incubator module, there are 2 messages logged -
also only ONCE on startup of application:
* A warning message by The JVM itsself ("WARNING: Using incubator
modules: jdk.incubator.vector"). This can't be suppressed and is
outside of Lucene's responsibility. If you don't want to see it,
complain at the JDK developers (see Dawid's message).
* A info message is logged that Lucene detected the Incubator module.
This is also logged once on startup. As before, you can suppress it
by adding a config file for java.util.logging (see
https://docs.oracle.com/en/java/javase/21/core/java-logging-overview.html
on how to configure it).
If you see a message on every search request then theres something
fundamentally broken:
* Do you spin up a Java VM on every search request - maybe doue to a
python or shell request on every query? If yes, then it will all be
slow and thats not a supported setup of Lucene. Every search request
will compile the whole Lucene application's bytecode by the Hotspot
VM on every request. This will be insanely slow. In that case you
will see the both messages every time!
* If you don't spin a VM on every search request, but still see the
INFO message (not the "WARNING: Using incubator modules:
jdk.incubator.vector"), then you have something that re-inits the
class loader every time. Is it a web application that gets restarted
on every request? Maybe something crashes the webapp every time and
Jetty or Tomcat resatarts it while reloading the web application?
Please look into this.
Uwe
Am 09.12.2025 um 15:47 schrieb Trevor Nicholls:
I recently upgraded our application from v8.6.3 to v10, and advanced to Java
21, and I immediately got both build and runtime errors and warnings about
vector incubators etc.
The warnings when I built the Lucene index suggested that I add
"--add-modules jdk.incubator.vector" to the java commandline.
Our application doesn't use any vector data types and so far as I know it
doesn't do any vector type comparisons either. Nevertheless I added this to
the commandline and I got a different message on execution:
[date & time]
org.apache.lucene.internal.vectorization.PanamaVectorizationProvider <init>
INFO: Java vector incubator API enabled: uses preferredBitSize=512; FMA
enabled
This goes to stderr, and I'd prefer to suppress it somehow.
The Lucene doco suggested that I could disable the FMA vector extension by
using the commandline option "-Dlucene.useVectorFMA=false" but this just
generated a different series of messages to the error log.
So far this is a trivial complaint that I wouldn't raise because the indexes
are not built at a high frequency and these unnecessary message lines don't
do any damage.
However the application which performs the searches is also generating error
output. If I include the --add-modules jdk.incubator.vector parameters,
every search request adds the lines
WARNING: Using incubator modules: jdk.incubator.vector
[date & time]
org.apache.lucene.internal.vectorization.PanamaVectorizationProvider <init>
INFO: Java vector incubator API enabled; uses preferredBitSize=256; FMA
enabled
to the error channel. Now this is a problem because the error file grows
like Topsy and any real errors in it are apt to get missed.
I don't really need to be told every time that I'm using vectorization
(although I'm not!) because I explicitly put it on the commandline. I only
expect to see a warning if something is wrong.
So that's the first question; is there some magical incantation that will
allow Lucene to think it's using vectorization and still keep the error log
clean?
The second question is one that probably reveals profound ignorance. The
option I was prompted to add to the application commandline refers to a jdk
module.
I'm building and testing this on a machine with the full JDK but it will be
deployed to machines that currently only have the JRE. Do I need the JDK
installed everywhere?
cheers
T
--
Uwe Schindler
Achterdiek 19, D-28357 Bremen
https://www.thetaphi.de
eMail:[email protected]
