#1 2017-09-04 07:54:51

Jasmine
Member
Registered: 2017-09-04
Posts: 3

Connection not stable

I can connect the database by jdbc, and run the report preview or download excel most of the time but sometimes error message will pop out:

The report could not be executed: net.datenwerke.rs.core.service.reportmanager.exceptions.ReportExecutorException: The report could not be executed: Could not open connection to: jdbc:mysql://[myconnection]:3306/[mydb]?autoReconnect=true with user: [myusername].
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure The last packet successfully received from the server was 1,236,864 milliseconds ago.

I need to re-click on the preview report link to make it works.

Any idea what's the issue? Thanks!

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#2 2017-09-04 08:03:11

eduardo
Administrator
Registered: 2016-11-01
Posts: 956
Website

Re: Connection not stable

Hi Jasmine,

how often does this happen to you? Does this always happen after a long inactivity period?

I think this is due to a long inactivity of the connections in the connection pool (you can see that the last packet was received more than 20 minutes ago). I see a similar issue here: https://stackoverflow.com/questions/298 … s-link-fai

Best regards,
Eduardo

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#3 2017-09-04 09:03:51

Jasmine
Member
Registered: 2017-09-04
Posts: 3

Re: Connection not stable

Hi Eduardo,

  Happen few times a day.

  Sometimes it happened just right after I've login-ed. It said the last packet was received more than 20 mins but the real world was, I keep using it.
  Here're the actions of 1 of the cases:

1) login as admin
2) update the SQL of 1 of the report
3) open the report template to check if the changes are fine
4) click on preview
5) error pop out (sometimes, some of the data loaded on the page)

  If I using Admin login to open a saved report that use using by another user but idle for > 20 mins, would that lead to that error message?

Regards,
Jasmine

Last edited by Jasmine (2017-09-04 10:31:03)

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#4 2017-09-04 11:09:41

eduardo
Administrator
Registered: 2016-11-01
Posts: 956
Website

Re: Connection not stable

Hi Jasmine,

autoReconnect=true is not recommended, refer to the comment here: https://stackoverflow.com/questions/259 … t-47727077
"Worth noting this method isn't recommended by the MySQL Connector/J documentation "because it has side effects related to session state and data consistency when applications don't handle SQLExceptions properly, and is only designed to be used when you are unable to configure your application to handle SQLExceptions resulting from dead and stale connections properly"."

Could you please try to configure the connection pool as stated here: https://reportserver.net/en/guides/conf … tasources/
Change the file /fileserver/etc/datasources/pool.cf and add:
testConnectionOnCheckout=true
testOnBorrow=true

For example (with the default config):
<configuration>
    <pool>
        <defaultconfig>
            <maxPoolSize>40</maxPoolSize>
            <initialPoolSize>10</initialPoolSize>
            <acquireRetryAttempts>10</acquireRetryAttempts>
            <acquireRetryDelay>500</acquireRetryDelay>
            <checkoutTimeout>60000</checkoutTimeout>
            <maxConnectionAge>7200</maxConnectionAge>
            <maxIdleTime>3600</maxIdleTime>
                        <testConnectionOnCheckout>true</testConnectionOnCheckout>
                        <testOnBorrow>true</testOnBorrow>
        </defaultconfig>
        <pool16>
            <acquireRetryAttempts>20</acquireRetryAttempts>
        </pool16>
    </pool>
</configuration>

Then open your console and type "config reload". For making sure the settings are read, please restart your tomcat.

Does this help?

Regards,
Eduardo

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#5 2017-09-05 11:00:38

Jasmine
Member
Registered: 2017-09-04
Posts: 3

Re: Connection not stable

Thanks!
I'll have a try and monitor for a week to see.

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#6 2017-09-25 12:50:07

eduardo
Administrator
Registered: 2016-11-01
Posts: 956
Website

Re: Connection not stable

Hi Jasmine,

did this work?

Regards,
Eduardo

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#7 2019-02-01 07:54:21

phenaut
Member
From: FRANCE
Registered: 2017-10-30
Posts: 12

Re: Connection not stable

Hello,
moving from 3.0.3 to 3.0.5, I have now approximatly the same issue, i see the server is 35 minutes late, even when i changed the system date it moves to 35 minutes late some time ago....
any idea ?
under investigation from my side...

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#8 2019-02-01 08:35:23

eduardo
Administrator
Registered: 2016-11-01
Posts: 956
Website

Re: Connection not stable

Hi phenaut,

this thread is about connection issues with the connection pool. If I understand correctly, your issue is with the server's time (system date). If this is correct, please open a new thread for new unrelated topics.

Regards,
Eduardo

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#9 2019-02-01 15:30:37

Aniello
Member
Registered: 2018-09-09
Posts: 15

Re: Connection not stable

Hi Eduardo

We are also experiencing this but only when the data sits on MariaDB - we switched to MySQL and this problem went away. Will try the above suggestion - tx

Best Regards
Aniello

Last edited by Aniello (2019-02-01 15:31:48)

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