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Oracle LogMiner

BladePipe uses LogMiner to synchronize the incremental data in Oracle. This article describes the preparations before data synchronization.

Step 1: Enable LogMiner​

Non-RAC Oracle​

  1. Log on to an Oracle database (e.g.,sqlplus) using a user with DBA permissions.
  2. Query the database log mode. 
    select dbid,name,log_mode from v$database;
  • If ARCHIVELOG is returned for log_mode, then skip the following steps.
  • If NOARCHIVELOG is returned for log_mode, then continue the following steps.

  1. Shut down the database.

    shutdown immediate;

  2. Start up and mount the database.

    startup mount;

  3. Enable ARCHIVELOG mode and open the database.

    alter database archivelog;
    alter database open read write;

RAC Oracle​

  1. Stop, start, and mount a database in the shell of one of the RAC Oracle nodes.

    srvctl stop database -d <database name>
    srvctl start database -d <database name> -o mount

  2. Log on to the database (e.g.,sqlplus) using an account with DBA permissions and enable ARCHIVELOG mode.

    alter database archivelog;

  3. In the shell of one of the RAC Oracle nodes, restart the database.

    srvctl stop database -d <database name>
    srvctl start database -d <database name>

  4. Log on to the database (e.g.,sqlplus) using an account with DBA permissions and check if the database is in ARCHIVELOG mode.

    select log_mode from v$database;

Step 2: Enable Supplemental Logging​

  1. Check if the supplemental logging is enabled at the database level.

    tip

    If 'YES' or 'Implicit' is returned for any of the following SQL fields, skip this step.

    select supplemental_log_data_min min, supplemental_log_data_pk pk,supplemental_log_data_ui ui, supplemental_log_data_all all_cols from v$database;

  2. Enable minimal supplemental logging at the database level.

  • Pluggable Database (PDB) 
    alter session set container=cdb$root;

    alter database add supplemental log data;
  • Container Database (CDB) 
    alter database add supplemental log data;
  1. (Option 1, Recommended) Enable all column logging at the database level.

  • Pluggable Database (PDB)

    alter session set container=cdb$root;

    alter database add supplemental log data (all,primary key,unique) columns;

  • Container Database (CDB)

    alter database add supplemental log data (all,primary key,unique) columns;

    (Option 2) Enable supplemental logging at the table level in Step 3.

    alter table <schema name>.<table name> add supplemental log data (all,primary key,unique) columns;

Step 3: Create a User and Grant Permissions​

Pluggable Database（PDB）​

The version of Oracle is 12c, 18c, 19c or 21c.

  1. Create a user under cdb$root, usually in the format c##<custom name>.

    alter session set container=cdb$root;
    create user <custom name> identified by <custom password> container=all;

  2. Grant general permissions.

    grant create session, select_catalog_role,logmining, execute_catalog_role to <custom name> container=all;
    tip

    Not all Oracle versions have the permission logmining. If the Oracle version you used doesn't have the permission logmining, please delete logmining in the above statement.

  3. Grant permissions related to LogMiner.

    grant execute on sys.dbms_logmnr to <custom name>;
    grant execute on sys.dbms_logmnr_d to <custom name>;

    grant select on v_$logmnr_contents to <custom name>;
    grant select on v_$archived_log to <custom name>;
    grant select on v_$log to <custom name>;
    grant select on v_$logfile to <custom name>;
    grant select on v_$logmnr_logs to <custom name>;

  4. Grant permissions related to tables.

    alter session set container=<pdb name>;

    grant select,alter on <schema>.<table> to <custom name>;
    ... select,alter(Autoopen and Complete Log) permissions for the table you want to migrate and synchronize. ...

Container Database (CDB)​

The version of Oracle is 11g, 12c, 18c, 19c or 21c.

  1. Create a user.

    create user <custom name> identified by <custom password>;

  2. Grant general permissions.

    grant create session, select_catalog_role, logmining, select any transaction, select any table to <custom name>;
    tip

    Not all Oracle versions have the permission logmining. If the Oracle version you used doesn't have the permission logmining, please delete logmining in the above statement.

  3. Grant permissions related to LogMiner.

    grant execute on sys.dbms_logmnr to <custom name>;
    grant execute on sys.dbms_logmnr_d to <custom name>;

    grant select on v_$archived_log to <custom name>;
    grant select on v_$logmnr_contents to <custom name>;
    grant select on v_$log to <custom name>;
    grant select on v_$logfile to <custom name>;
    grant select on v_$logmnr_logs to <custom name>;

  4. Grant permissions related to tables.

    grant select,alter on <schema>.<table> to <custom name>;
    ... select the table you want to migrate to,alter(Autocomplete Log) permissions granted ...