Help Center/ GaussDB(DWS)/ Developer Guide/ Standard data warehouse (8.1.3.x)/ GUC Parameters of the GaussDB(DWS) Database/ Write Ahead Logs/ Checkpoints
Updated on 2023-12-29 GMT+08:00
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Checkpoints

checkpoint_segments

Parameter description: Specifies the minimum number of WAL segment files in the period specified by checkpoint_timeout. The size of each log file is 16 MB.

Type: SIGHUP

Value range: an integer. The minimum value is 1.

Default value: 64

Increasing the value of this parameter speeds up the export of big data. Set this parameter based on checkpoint_timeout and shared_buffers. This parameter affects the number of WAL log segment files that can be reused. Generally, the maximum number of reused files in the pg_xlog folder is twice the number of checkpoint segments. The reused files are not deleted and are renamed to the WAL log segment files which will be later used.

checkpoint_timeout

Parameter description: Specifies the maximum time between automatic WAL checkpoints.

Type: SIGHUP

Value range: an integer ranging from 30 to 3600 (s)

Default value: 15min

If the value of checkpoint_segments is increased, you need to increase the value of this parameter. The increase of them further requires the increase of shared_buffers. Consider all these parameters during setting.

Parent topic: Write Ahead Logs