If you see the following error when starting MATLAB on a Linux machine:
[ERROR] InternalHttpAsyncClient - I/O reactor terminated abnormally <org.apache.http.nio.reactor.IOReactorException: Failure opening selector>org.apache.http.nio.reactor.IOReactorException: Failure opening selector
at org.apache.http.impl.nio.reactor.AbstractIOReactor.<init>(AbstractIOReactor.java:105)
at org.apache.http.impl.nio.reactor.BaseIOReactor.<init>(BaseIOReactor.java:87)
at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor.execute(AbstractMultiworkerIOReactor.java:320)
at org.apache.http.impl.nio.conn.PoolingNHttpClientConnectionManager.execute(PoolingNHttpClientConnectionManager.java:191)
at org.apache.http.impl.nio.client.CloseableHttpAsyncClientBase$1.run(CloseableHttpAsyncClientBase.java:64)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.io.IOException: Too many open files
at sun.nio.ch.IOUtil.makePipe(Native Method)
at sun.nio.ch.EPollSelectorImpl.<init>(EPollSelectorImpl.java:65)
at sun.nio.ch.EPollSelectorProvider.openSelector(EPollSelectorProvider.java:36)
at java.nio.channels.Selector.open(Selector.java:227)
at org.apache.http.impl.nio.reactor.AbstractIOReactor.<init>(AbstractIOReactor.java:103)
Answer
This error is related to MATLAB requiring a large number of file descriptors to run, which can exhaust the file descriptor limit set for a shell and its child processes.
To work around the issue, please try increasing the file descriptor limit. For example, you can check the file descriptor limit for your shell as follows:
1. For tcsh:
% limit desc
descriptors 1024
2. For bash:
$ ulimit -n
1024
In this case, we might try increasing the file descriptor limit to something like 10,000 to see if that resolves the issue. You can do this as follows:
1. For tcsh:
% limit desc 10000
2. For bash:
$ ulimit -n 10000
Then, start MATLAB.
