Proving the Restore, Part 10: Can You Reach That Point in Time?
Someone asks you to restore a database to 14:30 yesterday, just before a bad deployment. The answer is either a time estimate or “the closest I can get is 14:15”, and which one it is…
Proving the Restore, Part 8: Proving the Log Chain Has No Gaps
Restoring a full backup and then a hundred log backups works only if the logs form an unbroken sequence. One missing backup in the middle and the restore stops there, with the database still in…
Proving the Restore, Part 7: One File, Hundreds of Backup Sets
Point RESTORE HEADERONLY at a full backup and you get one row. Point it at the file a fifteen-minute log backup job has been appending to since Sunday and you get several hundred. Each row…
How Much Transaction Log Does REORGANIZE Really Generate? I Measured It
A while back I published , including the classic advice: reorganize in the middle band of fragmentation, rebuild above it, because “reorganize only logs the pages it actually moves.” In a LinkedIn discussion, Jeff Moden…
Backup & Recovery from First Principles, Part 5: Restore Sequences and the STOPAT Rewind
The first four parts of this series were about taking backups. This one is about the operation they all exist for. A restore sequence is a small program you write under pressure, and its grammar…
Backup & Recovery from First Principles, Part 3: The Log Chain and How People Break It
showed that log backups form a linked list: each backup’s first_lsn equals the previous backup’s last_lsn. Point-in-time restore works by walking that list. Break one link and every log backup after the break is useless…