Technical troubleshooting and more

when working with EXTERNAL tables you should be aware of LIMIT FLAG REJECT LIMIT 0 which means that any null values in the external file will be rejected and this error will be raised when trying to access this table ORA-29913: error in executing ODCIEXTTABLEFETCH callout ORA-30653: reject limit reached if you want to see empty fields as NULL values row add this line to your table definition: MISSING FIELD VALUES ARE NULL if you want to ignore empty lines from being showed as rows add these two lines to your table definition: MISSING FIELD VALUES ARE NULL REJECT ROWS WITH ALL NULL FIELDS

First look for you session status: select * from v$session where status = 'ACTIVE'; then check the long operation table to try to estimate the progress pace SELECT ( sofar / totalwork) * 100 as percent , FROM v $ session_longops WHERE sofar <> totalwork If you encounter this wait event : " wait for unread message on broadcast channel"  probably your session is still alive and running

When trying to copy PDB using SQL> create pluggable database TARGET_PDB from SOURCE_PDB; you may face this error the solution is very simple, you need to increase the parmarter  DB_FILES SQL> show parameter db_files; NAME                                 TYPE        VALUE ------------------------------------ ----------- ------------------------------ db_files                             integer     200 key points: when PDB is closed - the files still exists but you won't see them when counting from  CDB_DATA_FILES view. to  drop a pluggabe database including his datafiles use this command: SQL> drop pluggable database PDB_NAME including datafiles;

This error means that your application (client) has lost the connection to mysql server when a session is exceeding the time out limit while idle you will hit this error or when there are network issues and packet loss. (you can define the packet size that above it this error is raised) so - go you you cnf file (the standard is my.cnf) unless you've changed it look for these parameters and use appropriate values per your needs. wait-timeout                   = 31536000 max-allowed-packet             = 32M if your mysql server is already running and you don't want to restart it, these parameters can be changed on the fly (dynamic parameters) you should use SET GLOBAL/SESSION command to change them full list of dynamic parameters: http://dev.mysql.com/doc/refman/5.7/en/dynamic-system-variables.html Enjoy