Oracle JDBC issue on Linux - IO Error: Connection reset

[KevinSheedy]

The Oracle JDBC driver has a known issue on some linux systems. When using flyway, it manifests itself as an intermittent failure with the message:

ERROR: Unable to obtain Jdbc connection from DataSource .... IO Error: Connection reset

The problem can be fixed by starting Java with the following JVM param:

-Djava.security.egd=file:/dev/../dev/urandom

To fix it on my system, I replaced this line in the flyway script:

"$JAVA_CMD" -cp "$CP" org.flywaydb.commandline.Main "$@"

With this one:

"$JAVA_CMD" -Djava.security.egd=file:/dev/../dev/urandom -cp "$CP" org.flywaydb.commandline.Main "$@"

Do you think it would be worth adding a feature to flyway to allow JVM params to be passed in as a setting, without having to modify the original flyway file?

[ThomasRasmussen]

I ran into problems with Connection Reset towards Oracle, and this option actually makes a big difference... My builds actually runs in less than 5 seconds where it would often fail after the first call to flyway.

Ie. if I did a flyway:info this would run OK once, but then the following flyway runs will fail with connection reset... Connecting to Oracle with ie. SQLDeveloper works fine, so it is not a DB issue.

Apparently it is an issue in Java: http://stackoverflow.com/questions/137212/how-to-solve-performance-problem-with-java-securerandom

[davidkarlsen]

Yes. The entropy problem exists on Linux. Which os are you running on?
17. sep. 2015 8:00 a.m. skrev "Thomas Rasmussen" notifications@github.com:

I ran into problems with Connection Reset towards Oracle, and this option
actually makes a big difference... My builds actually runs in less than 5
seconds where it would often fail after the first call to flyway.

Ie. if I did a flyway:info this would run OK once, but then the following
flyway runs will fail with connection reset... Connecting to Oracle with
ie. SQLDeveloper works fine, so it is not a DB issue.

Apparently it is an issue in Java:
http://stackoverflow.com/questions/137212/how-to-solve-performance-problem-with-java-securerandom

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#1077 (comment).

[ThomasRasmussen]

I'm running on Ubuntu 14.04 LTS running on VMWare.

I found a nice explanation here: http://www.usn-it.de/index.php/2009/02/20/oracle-11g-jdbc-driver-hangs-blocked-by-devrandom-entropy-pool-empty/

It would be nice to have this option inside flyway property file or something instead ;-)

[davidkarlsen]

There you go. I recommend installing the package haveged which fills dev
random
17. sep. 2015 9:44 a.m. skrev "Thomas Rasmussen" notifications@github.com:

I'm running on Ubuntu 14.04 LTS running on VMWare.

I found a nice explanation here:
http://www.usn-it.de/index.php/2009/02/20/oracle-11g-jdbc-driver-hangs-blocked-by-devrandom-entropy-pool-empty/

It would be nice to have this option inside flyway property file or
something instead ;-)

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#1077 (comment).

[axelfontaine]

Fixed.

[forestlcoder]

when I use more than 2 connections to get Oracle data by Flink JDBCInputFormatBuilder, it will throw Connection reset exception. I add -Djava.security.egd=file:/dev/../dev/urandom in my JVM params like this
java -XX:+UseG1GC -Xms60000M -Xmx60000M -XX:MaxDirectMemorySize=8388607T -Djava.security.egd=file:/dev/../urandom -Dlog.file=/data/flink/log/flink-sctele-taskmanager-4-ELK2.tianyiHD.log -Dlog4j.configuration=file:/usr/local/flink-1.4.2/conf/log4j.properties -Dlogback.configurationFile=file:/usr/local/flink-1.4.2/conf/logback.xml -classpath /usr/local/flink-1.4.2/lib/flink-python_2.11-1.4.2.jar:/usr/local/flink-1.4.2/lib/flink-shaded-hadoop2-uber-1.4.2.jar:/usr/local/flink-1.4.2/lib/log4j-1.2.17.jar:/usr/local/flink-1.4.2/lib/slf4j-log4j12-1.7.7.jar:/usr/local/flink-1.4.2/lib/flink-dist_2.11-1.4.2.jar::: org.apache.flink.runtime.taskmanager.TaskManager --configDir /usr/local/flink-1.4.2/conf
but it still don`t work for me.