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ReferenceApplies to: Unified engine deployments
[submission_defaults]

Settings

worker_scope

Chooses whether a worker is allocated for one task or reused within a workload run.
  • Default: "Task"
  • Type: choice: Task, Workload
Example "Task" gives tasks their own allocations. "Workload" lets tasks in the same run reuse a worker pool.

parallelism

Limits how many tasks in one workload run may execute at the same time.
  • Default: Unset
  • Type: integer; positive; optional
Example 2 allows up to two concurrent tasks. If unset, workload-scoped workers default to one; task-scoped workers have no additional cap here.

execution_target

Chooses the engine expected to execute the task.
  • Default: "DuckDb"
  • Type: choice: DataFusion, DuckDb
Example "DuckDb" selects Native Engine. DataFusion is another serialized target, but it needs a compatible executor; the current native worker starts Native Engine.

execution_timeout

Limits how long a task is allowed to execute.
  • Default: Unset
  • Type: duration; optional
Example { secs = 300, nanos = 0 } gives a task five minutes. Leaving this optional field unset gives the task no execution time limit.

compute_requirements.cpu_millicores

Sets the requested CPU capacity. A value of 1000 means one CPU.
  • Default: 2000
  • Type: integer; positive
Example 2000 requests two CPUs; 500 requests half a CPU. This is the allocation request, not a command to resize the controller.

compute_requirements.memory_bytes

Sets the memory requested for one worker allocation.
  • Default: 2147483648
  • Type: integer (bytes); positive
Example 2147483648 requests 2 GiB. For Kubernetes, the provider uses the allocation when setting the worker container’s memory request and limit.

max_attempts

Limits how many execution attempts may be made for a task.
  • Default: 3
  • Type: integer; positive
Example 3 allows up to three task attempts. An uncertain write still needs its saved outcome checked before another write attempt can be made.

missed_run_policy

Chooses what happens to scheduled occurrences that were missed.
  • Default: "RunOnce"
  • Type: choice: RunOnce, RunAll, Skip
Example If three scheduled times passed while the service was unavailable, RunOnce catches up once, RunAll considers all three, and Skip ignores them.

overlap_policy

Chooses what happens when a scheduled run is due while an earlier run is still active.
  • Default: "Wait"
  • Type: choice: Wait, Skip, Allow
Example Wait queues the next run, Skip ignores that overlapping occurrence, and Allow permits both runs to be active.

Execution tuning

compute_requirements.tuning

Sets detailed execution budgets within an allocation’s CPU and memory.
  • Default: Unset
  • Type: object; optional
Example For a two-CPU worker, set threads = 2 and explicit query, buffer, and spill budgets here. Omitted tuning values are calculated from the allocation.

compute_requirements.tuning.threads

Chooses how many execution threads one task may use within its assigned CPU allocation.
  • Default: Unset
  • Type: integer; positive; optional
Example For a task allocated 2000 millicores, 2 allows two execution threads. Leave it unset to derive a value from the allocation; setting more threads does not allocate more CPUs.

compute_requirements.tuning.query_memory_bytes

Sets how much of a worker’s allocated memory may be used by the query engine.
  • Default: Unset
  • Type: integer (bytes); positive; optional
Example On a 2 GiB worker, 1073741824 reserves a 1 GiB query budget. Leave room for connector buffers and process overhead; this budget cannot exceed 80% of the allocation.

compute_requirements.tuning.buffer_bytes

Sets the memory budget used for task data buffers.
  • Default: Unset
  • Type: integer (bytes); positive; optional
Example 67108864 gives a 64 MiB buffer budget. It must fit alongside query memory and the configured number of output buffers.

compute_requirements.tuning.batch_rows

Sets how many rows may be handled in one reader batch.
  • Default: Unset
  • Type: integer; positive; optional
Example 65536 reads up to 65,536 rows per batch when this setting is omitted. Smaller batches can reduce memory held at once; the maximum is 1048576.

compute_requirements.tuning.write_batch_rows

Sets the maximum rows per sink batch independently of reader batches. The executor also limits batching by its byte budget. One oversized input value may need a larger buffer.
  • Default: Unset; resolves to 65536
  • Type: integer; positive; at most 1048576; optional

compute_requirements.tuning.write_parallelism

Sets the number of worker-local Iceberg file writers. Writers use bounded queues and share a memory budget. All writers must finish before one Iceberg commit publishes their files.
  • Default: Unset; resolves to execution threads
  • Type: integer; positive; must not exceed execution threads; optional
Example On a four-core worker, write_parallelism: 4 allows four file writers. Each writer can encode and upload while the other writers continue. A one-core worker defaults to one writer.

compute_requirements.tuning.spill_bytes

Limits task data temporarily written to disk when execution needs it.
  • Default: Unset
  • Type: integer (bytes); optional
Example 8589934592 gives an 8 GiB task spill budget. Zero disables task spill, while an omitted value is calculated from allocation memory.

compute_requirements.tuning.output_buffer_batches

Limits how many output batches wait for the next consumer.
  • Default: Unset
  • Type: integer; positive; optional
Example 2 allows two batches to wait. Raising this can keep more data in memory; task tuning allows at most 32.

Resource budgets

Tuning is optional under each task’s compute_requirements object. Unset tuning derives values from the task allocation. Set task defaults here; tuning in workers.provisioners.<name>.capacity does not set task execution budgets. To make budgets explicit, set every tuning field. Threads cannot exceed rounded-up allocated CPUs. Query memory and the configured buffers must leave runtime overhead; individually valid limits can still be rejected together.
Last modified on November 4, 2026