To collect information about and determine whether the transmission performance needs to be tuned:

1. Periodically execute the hdestate command to collect information about Queue write position and Queue read position.
2. Obtain the value by subtracting the offset position of Queue read position from the offset position of Queue write position.
3. If the value obtained in step 2 has increased in proportion to the elapsed time, evaluate the following tuning items:
   
   • Transmission interval
   • Size of update information editing buffer
   • Transmission master process's transmission interval
   • Length of update information editing buffer
   • Interval at which the transmission process reads the extraction information queue file
   • Size of extraction information queue I/O buffer
   Note that if the import information queue file is full or a communication line error occurs, the value obtained in step 2 also increases in proportion to the elapsed time. If this is the case, eliminate the cause of the error, obtain the offset positions again, and then evaluate the change of offset and the elapsed time.
   

To collect information about and determine whether the import performance needs to be tuned:

1. Periodically execute the hdsstate command to collect information about Queue write position and Queue read position.
2. Obtain the value by subtracting the offset position of Queue read position from the offset position of Queue write position.
3. If the value obtained in step 2 has increased in proportion to the elapsed time, evaluate the following tuning items:
   
   • SQL performance
   • Import processing commit interval
   • Import processing commit interval when the transaction-based import method is used
   • Import processing commit interval when the table-based import method is used
   • Maximum number of update SQL statements in an import transaction
   • COMMIT issuance interval
   • Concurrent execution of import processing
   • Interval at which the import process reads the import information queue file

You can determine SQL performance by collecting HiRDB's SQL trace. To collect an SQL trace, you need to specify the PDSQLTRACE environment variable. In UNIX, specify the PDSQLTRACE environment variable in the target Datareplicator's environment variables. In Windows, specify this environment variable in the system environment variables or hirdb.ini. For details about PDSQLTRACE, see the manual HiRDB Version 9 System Definition.