Full or Incremental Phase Error: Got minus one from a read call

Scenarios

During a full or incremental synchronization with Oracle serving as the source, an error is reported, and the log information is as follows: service LOGMANAGER failed, cause by: Unable to connect to DBMS: url=jdbc:oracle:thin:@(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=*.*.*.*)(PORT=1521))(CONNECT_DATA=*)) user=*, Caused by: IO Error: Got minus one from a read call.

Possible Causes

• The source database server rejects access from the IP address of the DRS task.
• The source database connection information has changed.
• The number of connections to the source database has reached the upper limit.

Solution

1. Modify the sqlnet.ora file in $ORACLE_HOME/network/admin to allow the IP address of the DRS task to access the source database.
   • If a whitelist is used, TCP.INVITED_NODES must contain the DRS task IP address.
   • If a blacklist is used, TCP.EXCLUDED_NODES cannot contain the DRS task IP address.

2. Check whether the source database information (such as the IP address, port number, or service name/sid) is modified. If the source database information is modified, perform the following operations:
   • Restore the modified source database information. The DRS task will automatically retry to continue the synchronization task.
   • Create a synchronization task again.

3. Run the following commands to check whether the number of connections to the source database has reached the upper limit.
   • Run the following command to check the current number of connections:

     select count(*) from v$process;

   • Run the following command to check the maximum number of connections:

     select value from v$parameter where name ='processes';

   If the number of connections to the source database has reached the upper limit, run the following command to change the maximum number of connections allowed by the database:

   alter system set processes = 300 scope = spfile;

   Restart the database for the modification to take effect.