July 29, 2011 at 7:27 am
SQLRO (7/29/2011)
I wonder why the data is lost from both the log file(as the log reader software does not show any log entry) and data file.
Records are NEVER removed from the log file. They can be overwritten once not needed, but nothing ever removes log records
1. Due to some reason the log file could not be accessed by the SQL Server.
If that happened SQL would mark the database read-only immediately.
2. To make the daabase online SQL Server internally executed checkdb statement with allow data loss which put the database in this condition.
SQL will never execute any CheckDB, let along one with data loss, automatically.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
July 29, 2011 at 7:30 am
SQLRO (7/29/2011)
Actually nobody did the restore manually but the server was restarted once by the infra team...really not sure what has caused these entries in the error logs.
The only thing that causes those entries is someone restoring the database. From the looks of things, there was a hardware problem (the log is not available error) and in response someone restored a backup.
SQL won't just have restored it by itself, and the log messages are a very clear sign of RESTORE DATABASE FROM DISK being run and replacing the DB.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
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