Governance

Synchronization

Dash Core synchronizes the governance system via the masternode network as the last stage of the Masternode sync process (following the sync of sporks, the Masternode list, and Masternode payments).

The govsync message initiates a sync of the governance system. Masternodes ignore this request if they are not fully synced.

There are two distinct stages of governance sync:

1. Initial request (object sync) - requests the governance objects only via a govsync message sent with a hash of all zeros.

2. Follow up request(s) (vote sync) - request governance object votes for a specific object via a govsync message containing the hash of the object. One message is required for each object. Dash Core periodically (~ every 6 seconds) sends messages to connected nodes until all the governance objects have been synchronized.

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Governance Object Sync Limitation

Dash Core limits how frequently the first type of sync (object sync) can be requested. Frequent requests will result in the node being banned.

Masternodes respond to the govsync message with several items:

For Object Sync:

• First, the Masternode sends a ssc message (Sync Status Count) for govobj objects. This message indicates how many inventory items will be sent.

• Second, the Masternode sends an inv message for the govobj and govobjvote objects.

For Vote Sync:

• First, the Masternode sends a ssc message (Sync Status Count) for govobjvote objects. This message indicates how many inventory items will be sent.

• Second, the Masternode sends an inv message for the govobjvote object(s).

Once the syncing node receives the counts and inventories, it may request any govobj and govobjvote objects from the masternode via a getdata message.

Governance Sync Data Flow

Syncing Node Message	Direction	Masternode Response	Description
Initial request			Requests all governance objects (without votes)
govsync message	→		Syncing node initiates governance sync (hash set to all zeros)
	←	ssc message (govobj)	Number of governance objects (0 or more)
	←	inv message (govobj)	Governance object inventories
getdata message (govobj)	→		(Optional) Syncing node requests govobj
	←	govobj message	(If requested) Governance object
Follow up requests			Requests governance object (with votes)
govsync message	→		Syncing node requests governance sync for a specific governance object
	←	ssc message (govobjvote)	Number of governance object votes (0 or more)
	←	inv message (govobjvote)	Governance object vote inventories
getdata message (govobjvote)	→		(Optional) Syncing node requests govobjvote
	←	govobjvote message	(If requested) Governance object vote

Sentinel

Sentinel is a Python application that connects to a masternode's local dashd instance to run as an autonomous agent for persisting, processing, and automating Dash 12.1+ governance objects and tasks. Sentinel abstracts some governance details away from Dash Core for easier extensibility of the governance system in the future. This will allow the integration between Evolution and Dash Core to proceed more smoothly and enable new governance object additions with minimal impact to Dash Core.

Sentinel runs periodically and performs three main tasks as described below:
governance sync, governance object pruning, and superblock management. The governance object data is stored in a SQLite database.

Sentinel Sync

Sentinel issues a gobject list RPC command and updates its database with the results returned from dashd. When objects are removed from the network, they are purged from the Sentinel database.

Sentinel Prune

Sentinel 1.1.0 introduced proposal pruning which automatically votes to delete expired proposals following approximately half of a superblock cycle. This delay period ensures that proposals are not deleted prematurely. Prior to this, proposals remained in memory unless a sufficient number of masternodes manually voted to delete them.

Sentinel Superblock

Sentinel manages superblock creation, voting, and submission to dashd for network propagation.

Beginning ~3 days (1662 blocks) prior to a superblock, Sentinel selects one masternode per block to rank proposals. This ranking is used to determine what a candidate superblock (or "superblock trigger") should contain. Based on the results, it creates and broadcasts a new superblock trigger if a matching one was not found.

All masternodes vote for existing superblock triggers. Each masternode casts only 1 superblock trigger "Yes" vote per superblock cycle. It will vote "No" for any other triggers it receives.

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Single masternode trigger vote

Note: This means that proposal votes submitted after superblock trigger creation begins will not be counted by some masternodes (those that have already voted on a superblock trigger).

At the superblock height, the trigger with the most "Yes" votes is paid out by that block's miner.

Sentinel Ping

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Sentinel Ping Deprecation

Note: Sentinel Pings were deprecated by Dash Core v0.14

In Dash Core 12.2, use of the watchdog governance object type was replaced by integrating sentinel information into the masternode ping (mnp message) via Pull Request #1491.

From Dash Core 0.12.2 through Dash Core 0.13, Sentinel used the sentinelping RPC to update the masternode info and prevent it from entering a MASTERNODE_WATCHDOG_EXPIRED state.