I've been working with the class recently and taking notes on a few quirks and features.
#Sql bulk copy log series#
I hope this blog post series was helpful in understanding the basics of a transaction log file and some of key aspects to focus on while configuring log files for a database.The SqlBulkCopy class is invaluable for moving large amounts of data into SQL Server from a. On systems that are highly transaction-intensive, consider placing the transaction log file for a database on a SSD device. Transaction logs are write-intensive in nature. We all know that solid state drives (SSDs) are much faster than a traditional hard disk. Storage type plays a key role in the performance of a transaction log. However, you should always have backups run right after the loads to make sure there is minimal data loss. You can consider setting up an OLAP database in Simple recovery mode if the OLAP system is designed such that the data loads occur only once a day, which means data change operations occur only at a specific time. However, typical OLAP databases are not transaction-intensive.
#Sql bulk copy log full#
OLTP databases are transaction-intensive in nature, so it is always recommended to setup these types of databases in Full recovery mode, which means all data change operations are recorded in the log file and are truncated when the database is backed up. Always try to use a fixed value for growth instead of a percentage. It is always a good practice to determine what your data growth patterns are in order to determine the initial size and growth values for a log file. This can slow down database startup, log backup, and restore operations. If the log file becomes too big due to many small increments, there will be several hundreds – if not thousands – of virtual log files. Setting the autogrowth to a very small value can lead to a fragmented log file, which will cause performance issues. Additionally, it is also important to make sure you have regular backups of the database, because a database backup usually truncates the log file. The best method to determine the initial size of a log file is to understand the throughput of the operations that cause a transaction log to increase, then configure the log file so that you have enough space. There could be several reasons why the log file is full: the initial size was too small or few, transactions have gone wild, et cetera. Now, let’s ask ourselves: when does a transaction log grow? It grows when the log file is full. However, the guiding principle should be to make sure that the the initial size of the transaction log is set to a value so that the log does not have to use more disk size during business hours, as this could impact performance. Once the bulk load operation has been completed, you should switch back to Full recovery model. However, if there are bulk loads that are performed every so often, consider changing the recovery mode to “Bulk Logged” for the duration of the load operation to improve performance. It is always recommended to configure database-in-production environments to use the Full recovery model, as this provides the ability for point-in-time recovery. The database engine supports several types of checkpoints (automatic, indirect, manual, and internal) which can be configured. Since SQL Server does not provide point-in-time recovery for a database using the Simple recovery model, all transactions that are not active are truncated from the log when a checkpoint is issued. However, this this is not true: all operations are written to the log file before they are committed to the database. It is a common misconception that data modification operations are not written to the log file when a database uses the Simple recovery model because you rarely see the transaction log size increase. If the log is damaged or bulk-logged operations occurred since the most recent log backup, changes since that last backup must be redone. Reduces log space usage by using minimal logging for most bulk operations If the tail of the log is damaged, changes since the most recent log backup must be redone.Ĭan recover to a specific point in time, assuming that your backups are complete up to that point in time.Īn adjunct of the full recovery model that permits high-performance bulk copy operations. No work is lost due to a lost or damaged data file.Ĭan recover to an arbitrary point in time (for example, prior to application or user error). In the event of a disaster, those changes must be redone. Automatically reclaims log space to keep space requirements small, essentially eliminating the need to manage the transaction log space.Ĭhanges since the most recent backup are unprotected.
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