Indexing phase causes code completion latency

Background

When a large project is opened or after significant external changes, IntelliJ IDEA enters a project indexing phase. During this time the IDE builds file‑based and symbol indexes, which can temporarily disable or degrade code completion, go‑to‑declaration, and inspections.

Unresolved Decision

The IDE’s current behavior for user‑initiated code completion requests that overlap with active indexing is not fully documented. It is unclear whether such requests are blocked until indexing completes, queued for later processing, or served with partial results from already indexed scopes.

Specific Questions

• Does IntelliJ currently queue code completion requests during indexing, or does it block them until the indexing phase finishes?
• What criteria does the IDE use to decide whether a request can be served partially when only a subset of the requested module is indexed?
• Is there a configuration option or a planned feature that allows developers to influence this scheduling policy?