Saturday, June 24, 2006

Recoverying data from large dbs

As you can see from this forum thread some of ApexSQL Log (aka axLog) users are having performance problems with recovery of large dbs from detached (and in this case seemingly corrupted) MDF files. In this case it's a db with 220gb of data split in 4 files. In the current version of axLog (2005.02, which is comming out tomorrow) recovery process makes one pass through MDF files per recovered table. On the other hand we don't offer selection of tables to be recovered. Put these two things together and you get performance problems on very large dbs. We have been aware of this for a while so in next major version we will offer:
  1. Selection of tables to recover.
  2. Output of recovered data for each table into separate files.
This will allow users to select only what they need to recover and have it recovered in only one pass. We will offer this for recovery from detached MDF files and for the upcoming recovery from database backups.

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