question Re: error while running simple sqoop command in Archives of Support Questions (Read Only)

error while running simple sqoop command

hardikv_desai — Sat, 05 Aug 2017 20:37:43 GMT

sqoop-error.txt

Hi all,

i am getting this connection reset everytime i run any simple select sqoop command also.

kindly find attached file to look int the error.

plz do the needful if possible.

@Jay SenSharma

Re: error while running simple sqoop command

jsensharma — Sat, 05 Aug 2017 21:09:41 GMT

@hardik desai

It's basically a "connection reset" error.

17/08/05 19:02:46 ERROR manager.SqlManager: Error reading database metadata: java.sql.SQLRecoverableException: IO Error: Connection reset
java.sql.SQLRecoverableException: IO Error: Connection reset

- This either indicates a N/W issue or Oracle Terminating the connection.

- Is it happening for every connection request, or if you are throttling the connection requests to a couple per second, does it work better?

- Sometimes the DBMS can't handle lots of near-simultaneous connection requests. But If it happens with each request, every time, then it might be a DB a n/w issue.

- Another possible reason could be that for some reason the software cannot read from "dev/random" In such cases you should try with the "java.security.egd" property as following, Because sometimes due to the lack of a fast random number generation device on the host where the map tasks execute.

export HADOOP_OPTS=-Djava.security.egd=file:/dev/../dev/urandom
sqoop import -Dmapred.child.java.opts="-Djava.security.egd=file:/dev/../dev/urandom"

https://sqoop.apache.org/docs/1.4.6/SqoopUserGuide.html#_oracle_connection_reset_errors

Re: error while running simple sqoop command

hardikv_desai — Sat, 05 Aug 2017 21:18:35 GMT

@Jay SenSharma thank you for your reply...

To let you know that it happened with each request every time. I have checked from network end also by using telnet and tcpdump but still not sure about the cause of the error.

Re: error while running simple sqoop command

jsensharma — Sat, 05 Aug 2017 21:24:48 GMT

@hardik desai

Please try once:

# rm /dev/random
# ln -s /dev/urandom /dev/random

Re: error while running simple sqoop command

hardikv_desai — Sat, 05 Aug 2017 21:29:11 GMT

@Jay SenSharma i have tried with these commands and executed it 3 times. It worked everytime now. I suppose it is due to that bug only which you have shared.

Re: error while running simple sqoop command

jsensharma — Sat, 05 Aug 2017 21:32:47 GMT

@hardik desai

Good to know that you are able to run the command properly now. It would be great if you can mark the correct answer as "Accepted" (answered) that way it will help other HCC users to quickly navigate the answer.