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HOWTO: Speed Up Data Access by Using BeginTrans & CommitTrans
Article ID: Q146908

The information in this article applies to:
Microsoft Visual Basic for Windows Learning, Professional, and Enterprise Editions, versions 5.0, 6.0
Professional and Enterprise Editions of Microsoft Visual Basic, 16-bit, for Windows, version 4.0


SUMMARY
You can speed up database operations in a Microsoft Access database by using transactions. A transaction starts with a BeginTrans statement and ends with a CommitTrans or Rollback statement. However, for reasons relating to stack usage it is recommended that these code regions are kept as small as possible. This ensures optimal performance and reliability." For more information as to when to use transactions, please see the following article in the Microsoft Knowledge Base:


ARTICLE-ID: Q145757
TITLE : Ideas to Consider When Using Transactions


The sample program below is over 17 times faster when using BeginTrans/CommitTrans. Performance may vary on different computers.


MORE INFORMATION
You can tune the performance of Visual Basic by using transactions for operations that update data. A transaction is a series of operations that must execute as a whole or not at all. You mark the beginning of a transaction with the BeginTrans statement. You use the Rollback or CommitTrans statement to end a transaction.

You can usually increase the record updates per second (throughput) of an application by placing operations that update data within an Access Basic transaction.

Because Visual Basic locks data pages used in a transaction until the transaction ends, using transactions prevents access to those data pages by other users while the transaction is pending. If you use transactions in a multi-user environment, try to find a balance between data throughput and data access.

If database operations are not within a transaction, every Update method causes a disk write.

Transactions are very fast because they are written to a buffer in memory instead of to disk. CommitTrans writes the changes in the transaction buffer to disk.

Robust error trapping is important when using transactions to avoid losing writes if the program gets an error in the middle of a transaction...