log

1. A file that records some type of information. physical and logical. With an INFORMIX-OnLine database engine, a physical log contains images of entire pages before they were changed. Physical logs are used during fast recovery when INFORMIX-OnLine is coming up.

See also error log, file.

2. A logical log, sometimes called a transaction log, records changes performed on a database during the period the log was active. A logical log includes, as needed, images of the row before it was changed and images of the row after it was changed. Logical logs are used to roll back transactions, recover from system failures, and restore databases from archives.

See also commit, roll back, transaction.

3. The 4GL STARTLOG( ) function can specify an error log file in which to record runtime errors.