Imagine the following timeline:
- T0 = full backup
- T1 = log backup
- T2 = log backup
- T3 = log backup
- T4 = full backup
- T5 = log backup
After all the above have transpired, if you still have all the backup files, how would you restore to a point in time between T3 and T4?
My understanding is that the full backup at T4 should lead the log file to mark transactions between T0 and T4 as inactive, so in theory, the transaction log may no longer contain transactions from the time before T4. In particular, the log backup at T5 will only contain transaction information from the time after T4. Is this correct?