Q: How do I solve an out of memory (OOM) error when I use OBDUMPER to export data?
A: First, modify the memory parameter for the Java virtual machine (JVM) in the bin/obdumper script. Then, rule out the OpenJDK garbage collection (GC) bug.
Q: How do I run OBDUMPER in debugging mode for troubleshooting?
A: Run the debugging script in the bin directory.
Example: obdumper-debug.
Q: Why does the control file configured for a table fail to take effect when I import data to or export data from the table?
A: The name of the control file must be identical to the table name. By default, table names are in lowercase in the MySQL compatible mode and in uppercase in the Oracle compatible mode.
Q: Why does OBDUMPER not generate an empty data file when it exports an empty table?
A: By default, OBDUMPER does not generate an empty data file for an empty table. You can specify the --retain-empty-files option to generate an empty data file for an empty table.
Q: Why are command-line options not parsed as expected when I run the OBDUMPER script?
A: This issue may occur if command-line option values contain special characters. If you run OBDUMPER on Linux OS, a greater-than sign (>) in the password may cause the loss of all operational logs. This is because the greater-than sign (>) is a redirection operator. Therefore, you must use appropriate quotation marks to resolve this issue on different OS platforms.
Q: Why does sec.avg and min.avg show the similar export speeds when I run the OBDUMPER script?
A: sec.avg indicates the global average speed (in seconds), and min.avg indicates the average speed in the last minute (in seconds).
Q: What do I do if the Connection reset error is reported after I use the --query-sql option to specify large query statements for OBDUMPER?
A: Log on to the sys tenant, and set the client_tcp_user_timeout and server_tcp_user_timeout parameters of ODP to 0.
Q: What do I do if the following error is reported when I start OBDUMPER: Access denied for user 'root'@'xxx.xxx.xxx.xxx'?
A: By default, OBDUMPER requires the privileges of the root@sys user. If you have set a password for the root@sys user in the cluster, specify the password in the --sys-password option in the command.
Q: What do I do if the following error is reported when OBDUMPER is running: The target directory: "xxx" is not empty?
A: To prevent data overwriting, OBDUMPER checks whether the destination directory is empty before data export. You can specify the --skip-check-dir option to skip this check.
Q: What do I do if the following error is reported when OBDUMPER is running: Request to read too old versioned data?
A: The data version that the current query depends on has been recycled. You need to set an UNDO retention period based on the query.
For example, you can execute set global undo_retention=xxx. The default unit for the parameter is seconds.
Q: What do I do if the following error is reported when I query views on OBDUMPER: SELECT command denied to user 'xxx'@'%' for table SYS.XXX?
A: This error is reported because you are not authorized to access internal tables or views. Execute the following statement to obtain required privileges: GRANT SELECT SYS.XXX TO xxx;.