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Q: Got a question, when I try to delete an import from the import history
manager by selecting one of the imports, it asks me if I'm sure that i want
to delete the selected import. I say yes and it deletes all of them. Is
this a known bug? A: This is not a bug. It is by design. Here is the explanation: An import job can contain multiple log files. Each log file contains
thousands of log entries. Normally, each log entry imported into SQL would
be transacted but since SQL transactions are expensive (time consuming) we
enable the "bulk copy" option. This turns off transaction logging during
import. Turning off transaction logging means that individual log files can
not be backed out. What are the consequences of this? Well, you can only back-out an imported
JOB. You can't back out an imported LOG. If you need to back out individual
logs, you should import each log in a separate job. Another benefit of importing each log in a separate job is the ENTIRE job
gets loaded into memory during import. Clearly, if you have 30 days of logs
and each log is 10+ megabytes, you need 300+Mb of RAM to hold the job. If
you import each log in a separate job, you only need 10+Mb RAM. - Alan Stuart |
