25 Jan 98

Logging and recovery

The transaction log is no longer a "table" consisting of a linked list of pages. It does not compete with data pages in the buffer space. Instead, it is a set of logical files containing log rows. It will grow automatically. Truncation is quick.

Logical log files can be backed up as long as they dont contain active pages.

Backup can still be done while users are on-line. Microsoft reports minimal degradation (5%) in system throughput when this is done.

Restore automatically creates a database.

There is the capacity for incremental backups (all pages changed since last full backup). This will speed recovery. Log backups are still supported. [I have not figured out what the tradeoffs are here.] Files and file groups can be backed up so that one can recover from media failure or isolated corruption. This is primarily for very large databases with a tight backup window.

New Transact-SQL and Other Developer Features


Unicode is supported throughout SQL Server. There are several new Unicode datatypes:

NCHAR, NVARCHAR up to 4000 characters

NTEXT Unicode blob

Unicode object names permit up to 128 characters.


Many thanks to Sharon for providing these notes - drop her a note at sharond@compuserve.com and tell her thanks!