wf_instance Runtime Process Instance Table

One approval request = one row. Stores only "in-progress" instances; once ended, the entire row is migrated into wf_hi_instance.

Table Structure

Field	Type	Description
id	VARCHAR(36) PK	Instance UUID
process_id	VARCHAR(36)	The id of the process definition version row (runs against a pinned version)
business_key	VARCHAR(200)	Business key (the business system's unique number, e.g. an expense claim number)
name	VARCHAR(200)	Instance name (e.g. "Wang Qiang's leave request")
start_user_id	VARCHAR(36)	Initiator user ID (empty string when triggered by the system)
status	VARCHAR(20)	draft (draft; becomes active after activation) / active / completed / suspended / terminated (cancelled / failed are reserved enum values with no write path in the current version)
variables	TEXT	Process variables JSON — the submitted form data is packed under msg and can be added to or modified during execution
current_activity	VARCHAR(100)	Node definition ID where execution currently sits
priority	INTEGER	Priority (higher = more urgent, default 50)
parent_id	VARCHAR(36)	Parent instance ID — links a subprocess back to its main process
tenant_id	VARCHAR(100)	Tenant ID (SaaS multi-tenant)
created_by / created_at / updated_by / updated_at	—	Audit
end_reason	VARCHAR(2000)	Completion/termination reason (includes error details)
duration	BIGINT	Running duration (milliseconds)
ended_at	TIMESTAMPTZ	End time

Indexes cover the high-frequency query dimensions: status, tenant_id, business_key, parent_id, created_at DESC, priority DESC, created_at ASC (to-do list / claim ordering), plus the composite indexes (tenant_id, status, created_at DESC) (admin lists) and (tenant_id, start_user_id) ("initiated by me").

variables: Form Data as Process Variables

The form values submitted at initiation are packed wholesale into variables:

{ "days": 5, "reason": "Family matters", "managerId": "mgr001" }

• Conditional gateways (switch) read them through expressions such as msg.days
• userTask candidate configuration can be resolved from variables via ${msg.xxx} (e.g. scenarios where the initiator picks the approvers)
• AI/HTTP/automation nodes likewise fetch values via ${msg.xxx}

Subprocess

A subProcess node creates a new instance whose parent_id points to the main instance; after the subprocess finishes its own end node, the result variables are carried back to the main process and execution continues.

Lifecycle

The moment it ends: the row migrates into wf_hi_instance, back-filling duration / ended_at / end_reason; on withdraw, end_reason records "Withdrawn by applicant".

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