Hermes can be configured in order to clear packets which haven't been relayed. This can happen if there wasn't a relayer instance running when the packet event was submitted or if there was an issue relaying the packet.
There are three different configurations to determine when Hermes will clear packets.
Two of these configurations are global to all chains and are in the
[mode.packet] ... clear_on_start = true
This configuration is used to specify if Hermes should query and relay pending packets when starting the instance. If set this will only trigger once per running instance.
NOTE: If this configuration is enabled Hermes will need to scan for channels as the pending packets will require the channel worker, refer to the Slow start section for more information.
[mode.packet] ... clear_interval = 100
This configuration defines how often Hermes will verify if there are pending packets and relay them. The value is the number of blocks observed, so the time between each clearing might very from chain to chain.
The third configuration is specific for each chain.
[[chains]] ... clear_interval = 50
clear_interval can be specified for each chain, this value is also in number of blocks. This configuration will override the clear interval value for the specific chain and can be used if chains need to have different clear values. This configuration is optional, if it is not set the global value will be used.