When I set -Djdk.tracePinnedThreads=short, then I see this:
…
Thread[#41,ForkJoinPool-1-worker-4,5,CarrierThreads]
com.mysql.cj.jdbc.ConnectionImpl.isValid(ConnectionImpl.java:2516) <==
monitors:1
Thread[#39,ForkJoinPool-1-worker-2,5,CarrierThreads]
com.mysql.cj.jdbc.ConnectionImpl.isValid(ConnectionImpl.java:2516) <==
monitors:1
Thread[#41,ForkJoinPool-1-worker-4,5,CarrierThreads]
com.mysql.cj.jdbc.ConnectionImpl.setAutoCommit(ConnectionImpl.java:2005)
<== monitors:1
Thread[#43,ForkJoinPool-1-worker-5,5,CarrierThreads]
com.mysql.cj.jdbc.ClientPreparedStatement.executeInternal(ClientPreparedStatement.java:893)
<== monitors:1
com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdateInternal(ClientPreparedStatement.java:1061)
<== monitors:1
com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdateInternal(ClientPreparedStatement.java:1009)
<== monitors:1
Thread[#43,ForkJoinPool-1-worker-5,5,CarrierThreads]
com.mysql.cj.jdbc.ConnectionImpl.commit(ConnectionImpl.java:791) <==
monitors:1
Thread[#43,ForkJoinPool-1-worker-5,5,CarrierThreads]
com.mysql.cj.jdbc.ConnectionImpl.setAutoCommit(ConnectionImpl.java:2005)
<== monitors:1
…
I started digging into the MySQL client code:
https://github.com/mysql/mysql-connector-j/blob/8.0.33/src/main/user-impl/java/com/mysql/cj/jdbc/ConnectionImpl.java
This class is littered with synchronized blocks, so now this makes sense to me
why virtual threads would take longer than a regular OS thread.
Regards,
William Crowell
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