Workflow uses several Glide events.

Table 1. Workflow Glide events
EventDescriptionPurposeTo UseSourceThreadListeners
Insert Global event set upon the insert of a GlideRecord that causes the script engine, and through that the workflow engine, to wake up. Starts workflows that are associated with the current GlideRecord either by reference, as in request items and SLA timers, or by conditions associated with the GlideRecord's table. There is no explicit customer-facing use for this in a workflow. It is part of the Glide engine, and with this event, the only thing workflows can do is start. Workflows can also be started manually using a script. Workflow Engine, RunEngine Current thread, current mutex User action of insert
Update Global event set upon the update of a GlideRecord that causes the script engine, and through that the workflow engine, to wake up. Looks to the Workflow Context [wf_context] table to find running workflows that are associated with the current GlideRecord by document ID. There is no explicit customer-facing use for this in a workflow. It is part of the Glide engine, and with this event, the only thing workflows can do is advance through the next set of transitions. Workflow Engine, RunEngine Current thread, current mutex User action of update of a GlideRecord
Delete Global event set upon the delete of a GlideRecord that causes the script engine, and through that the workflow engine, to wake up. Looks to the Workflow Context [wf_context] table to find running workflows that are associated with the current GlideRecord by document ID. There is no explicit customer-facing use for this in a workflow. It is part of the Glide engine, and with this event, the only thing workflows can do is advance through the next set of transitions. Workflow Engine, RunEngine Current thread, current mutex User action of delete of a GlideRecord
Query Global event set upon the query of the Glide database that causes the script engine, and through that the workflow engine, to wake up. Looks to the Workflow Context [wf_context] table to find running workflows that are associated with the current GlideRecord by document ID. There is no explicit customer-facing use for this in a workflow. It is part of the Glide engine, and with this event, the only thing workflows can do is advance through the next set of transitions. Workflow Engine, RunEngine Current thread, current mutex User action of query of a GlideRecord