10:45 you started your sp for inserting and if your insert completed at 10.46 and then you started, Full backup - Backup file having all Transaction.
10:45 you started insert and its taken 10.50 for Insert your backup started at 10.46 and its completed at 10.49 - Yourbackup file having all transaction
10:45 you started insert and its taken 10.50 ,backup started at 10.46 and its completed at 10.50 - Your backup file dont have last one min of data
Note : Its not depand at what time you startd insert - Its depand on backup duration. how much time you backup will run ,at that duration how many transation has happend its contain all.
One more very Imp thing what you inserted (commited or uncommited ) - You are doing same above process but what you have inserted is uncommited. Then also your backup file having all transaction but whan you will do restore, SQL server will do recovery and all uncommited data will be rollforward
and you will lose all uncommited data.
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