GTM Parameters

log_min_messages

Parameter description: Specifies which level of messages will be written into server logs. Each level covers all the levels following it. The lower the level is, the fewer messages will be written into the log.

If the values of client_min_messages and log_min_messages are the same, they indicate different levels.

Type: SUSET

Valid values: enumerated values. Valid values are debug, debug5, debug4, debug3, debug2, debug1, info, log, notice, warning, error, fatal, and panic. For details about the parameters, see Table 1.

Default value: warning

enable_multi_sequence_file

Parameter description: Specifies whether to split the gtm.sequence file in the GTM. After this parameter is enabled, sequence persistence operations are grouped by UUID, improving concurrency performance. This parameter is supported only by clusters of version 9.1.1.300 or later.

Type: SIGHUP

Value range: Boolean

• on: The gtm.sequence file in the GTM is split.
• off: The gtm.sequence file in the GTM is not split.

Default value: off

• After this parameter is enabled, the switchover starts and cannot be rolled back even if the parameter is disabled again. Sequence persistence operations are grouped by UUID and depend on:
  1. Whether enable_multi_sequence_file is enabled.
  2. Whether the sequence directory exists after splitting.

• Cluster upgrade scenarios: Do not enable this parameter during the upgrade observation period. After submitting the upgrade, you can either enable this function through a step-by-step switchover during operation or enable it immediately and start the GTM for a full switchover at startup.
• Cluster creation scenarios: Enable this parameter when the GTM is started. New clusters do not involve file switchover. You can enable this parameter when GTM is started.
• If the switchover is performed during operation, the final file switchover is completed only after the seq operation has overwritten all partitions. If some seq partitions are not modified for a long time, they will remain in the intermediate state for a long time. The intermediate state does not affect the seq operation performance. You can create more than 128 new sequences to activate the final switchover.
• According to the DWS data verification, when there are 100,000 sequence data records and this parameter is set to on before GTM is started, no extra time is required even if a full switchover is used.