How can we help you today? How can we help you today?

Using a SQL Backup file for comparison

Where is the 'work' done for retrieving items/data out of a file created from SQL Backup?

Should I expect time for the retrieval to take as long as a restore would take?
meklembl
0

Comments

3 comments

Sort by
  • Brian Donahue
    Hi Larry,

    Restoring a single table shouldn't take as long as restoring the whole backup file. The way it's been explained to me is that Data Compare implements a "page reader" that dumps the pages for individual tables. Once the initial read of the backup's schema is done, it is relatively quick to restore a single table because only the table's pages are dumped from the backup sequentially.
    Brian Donahue
    0
  • meklembl
    That makes sense, but the reason I ask the first question is because the tables that are the basis for the compare comprise about 25% of the space for the database. So I began to wonder, where this data was being put in respect to the server and or client. The backup file is a compressed SQL Backup file located on a networked file server.
    Thanks,
    Larry
    meklembl
    0
  • Robert C
    Hi,

    The comparison is done by the SQL Data Compare client - so in the case of a live database, it pulls the rows back from SQL Server, and in the case of a backup file, it'll read the contents of the file back to the client app as well. During a comparison, the data is stored on disk in the temporary directory of the machine running SQL Data Compare.

    For backup files, the data never goes to SQL Server at all - we read the file directly.

    As for speed, I'd recommend using a clustered index as your comparison key if at all possible - it's quite significantly faster when reading backup files.

    Hope that helps,
    Rob
    Robert C
    0

Add comment

Please sign in to leave a comment.