Log buffers

TA-LOG buffer

When operating with transaction logging enabled, the DBH creates what is known as the TA-LOG buffer. The TA-LOG buffer is implemented as an alternating buffer, in other words it consists of two buffers into which the DBH alternately writes backup information. As soon as a buffer is full, its contents are transferred to the current TA-LOG file (see section “Transaction log files TA-LOG” ). While the information is being transferred, the DBH writes the backup information to the other buffer.

CAT-LOG and DA-LOG buffers

For each database, the DBH maintains a so-called CAT-LOG buffer and a DA-LOG buffer in which it temporarily stores the statements for CAT logging or DA logging before they are transferred to the CAT-LOG or DA-LOG file ).