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Applies to: Embedded ❌, Enterprise ✅ Cache Prewarm loads the tiered index cache a plan executor keeps as part of Enterprise’s serving layer, instead of leaving it to fill lazily on first read. You configure which tables to prewarm; on startup, each plan executor loads those tables’ indexes into cache before it joins the fleet. The executor does not accept queries until prewarming finishes, so it never serves a request against a cold cache. LanceDB Embedded has no such cache, so there is nothing for it to warm there. Embedded does have its own, separate prewarm_index() on a table — an idempotent hint that loads a built index into memory ahead of a query.

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Why it matters

Without prewarming, a fresh or restarted executor would fill its indexes lazily, so the first queries it serves pay the cost of loading and deserializing them from object storage. Holding the executor out of the fleet until its configured tables are warm means every query it ever serves gets a warm cache, so performance stays consistent through restarts and rollouts instead of dipping right after each one. Contact us to learn more about how prewarming is configured for your deployment.

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What to read next

Data Page Cache

The raw-data-page cache — a separate cache from the one prewarm fills.

Tiered Index Cache

The deserialized-index cache prewarm fills.

Architecture

Where plan executors and query nodes sit in the serving fleet.