Product Documentation

Database Administrator's Guide

Previous Topic

Next Topic

Checkpoint Efficiency

Checkpoints are point-in-time snapshots of FairCom DB transaction states. FairCom DB writes checkpoints to the current transaction log at predetermined intervals. The most recent checkpoint entry placed in the transaction logs identifies a valid starting point for automatic recovery.

The interval at which checkpoints are written to the transaction log is determined by the server's CHECKPOINT_INTERVAL configuration keyword. This keyword specifies the number of bytes of data written to the transaction logs after which the server issues a checkpoint. It is ordinarily about one-third (1/3) the size of one of the active log files (Lnnnnnnn.FCS).

High transaction rate environments tend to generate large numbers of dirty cache pages which are flushed to disk during checkpoint processing. FairCom recommends increasing the checkpoint interval in these cases such that checkpoints occur less frequently reducing the volume of data flushed during the checkpoint. This can reduce the periodic latencies observed during checkpoint processing resulting in "flatter" overall I/O rates, and generally, overall better throughput.