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jdbc.connection.is.valid error and Unknown initial character set index '255' received from server occur. how i fix these problems? please help me
Environment Knowage 7.4 Windows 10 Tomcat 8.5.50
asked Apr 26, 2021 in General Configuration by ramin (390 points) | 1 view
Hi ramin,

can you attach screenshots of your DataSource coonfigurations, and the query you are trying to use?

Thanks,
Marco

hi Marco, thank you for answering my question. here you are.

1 Answer

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Hi ramin,

unfortunately I cannot see very well the screenshots you posted.

I suggest you to follow these steps:

  • leave characterEncoding out of the Connector/J connection string
  • configure the MySQL server with character_set_server=utf8mb4
  • download and use the latest version of the mysql connector/J driver
Hope this helps,
Bye.

Marco
answered Apr 30, 2021 by mbalestri (9,250 points)
selected Jun 14, 2021 by emarchis

Hi, Marco

All you says I did but there is no any changes . still errors occur.

This is a Query: 

select iccid, phone_number, smsc, event_date, message_state , messages_text from sentsms where phone_number = ?

Hi, can you please attach log files of the error?

Also, I see a question mark "?" in your query, were you trying to use prepared statements? Try a simple "select 1 from dual" as a first try, and see if it works.

Bye,
Marco
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