Runtime

The runtime section specifies configuration settings for the Spice runtime.

runtime.dataset_load_parallelism

This setting specifies the maximum number of datasets that can be loaded in parallel during startup. By default, the number of parallel datasets is unlimited.

runtime.results_cache

The results cache section specifies runtime cache configuration. Learn more.

runtime:
  results_cache:
    enabled: true
    cache_max_size: 128MiB
    item_ttl: 1s

Parameter name	Optional	Description
enabled	Yes	Defaults to true.
cache_max_size	Yes	Maximum cache size. Defaults to 128MiB.
eviction_policy	Yes	Cache replacement policy when the cache reaches cache_max_size. Defaults to lru, which is currently the only supported value.
item_ttl	Yes	Cache entry expiration duration (Time to Live). Defaults to 1 second.
cache_key_type	Yes	Determines how cache keys are generated. Defaults to plan. plan uses the query's logical plan, while sql uses the raw SQL query string.
hashing_algorithm	Yes	Selects which hashing algorithm is used to hash the cache keys when storing the results. Defaults to siphash. Supports siphash or ahash.

Choosing a cache_key_type

• plan (Default): Uses the query's logical plan as the cache key. Matches semantically equivalent queries but requires query parsing.
• sql: Uses the raw SQL string as the cache key. Provides faster lookups but requires exact string matches. Queries with dynamic functions, such as NOW(), may produce unexpected results. Use sql only when results are predictable.

Use sql for the lowest latency with identical queries that do not include dynamic functions. Use plan for greater flexibility.

Choosing a hashing_algorithm

• siphash (Default): Uses the SipHash1-3 algorithm for hashing the cache keys, the default hashing algorithm of Rust. This hashing algorithm is a secure algorithm that implements verified protections against "hash flooding" denial of service (DoS) attacks. Reasonably performant, and provides a high level of security.
• ahash: Uses the AHash algorithm for hashing the cache keys. The AHash algorithm is a high quality hashing algorithm, and has claimed resistance against hashing DoS attacks. AHash has higher performance than SipHash1-3, especially when used with a plan cache_key_type.

Consider using ahash if maximum performance is most important, or where hashing DoS attacks are unlikely or a low risk. More information on the security mechanisms of AHash are available in the AHash documentation.

runtime.shutdown_timeout

Controls how long Spice waits for connections to be gracefully drained and for components to shut down cleanly during runtime termination. Defaults to 30 seconds.

runtime:
  shutdown_timeout: 1m

runtime.tls

The TLS section specifies the configuration for enabling Transport Layer Security (TLS) for all endpoints exposed by the runtime. Learn more about enabling TLS.

In addition to configuring TLS via the manifest, TLS can also be configured via spiced command line arguments using the --tls-enabled true flag along with --tls-certificate/--tls-certificate-file and --tls-key/--tls-key-file.

runtime.tls.enabled

Enables or disables TLS for the runtime endpoints.

runtime:
  tls:
    ...
    enabled: true # or false

runtime.tls.certificate

The TLS certificate to use for securing the runtime endpoints. The certificate can also come from secrets.

runtime:
  tls:
    ...
    certificate: |
      -----BEGIN CERTIFICATE-----
      ...
      -----END CERTIFICATE-----

runtime:
  tls:
    ...
    certificate: ${secrets:tls_cert}

runtime.tls.certificate_file

The path to the TLS PEM-encoded certificate file. Only one of certificate or certificate_file must be used.

runtime:
  tls:
    ...
    certificate_file: /path/to/cert.pem

runtime.tls.key

The TLS key to use for securing the runtime endpoints. The key can also come from secrets.

runtime:
  tls:
    ...
    key: |
      -----BEGIN PRIVATE KEY-----
      ...
      -----END PRIVATE KEY-----

runtime:
  tls:
    ...
    key: ${secrets:tls_key}

runtime.tls.key_file

The path to the TLS PEM-encoded key file. Only one of key or key_file must be used.

runtime:
  tls:
    ...
    key_file: /path/to/key.pem

runtime.task_history

The task history section specifies runtime task history configuration. For more details, see the Task History documentation.

runtime:
  task_history:
    enabled: true
    captured_output: none
    retention_period: 8h
    retention_check_interval: 15m

Parameter name	Optional	Description
enabled	Yes	Defaults to true.
captured_output	Yes	Specifies the level of output captured by the task history table. Defaults to none.
retention_period	Yes	Specifies how long records in the task history table are retained. Defaults to 8h (8 hours).
retention_check_interval	Yes	Specifies how often old records are checked for removal. Defaults to 15m (15 minutes).

runtime.cors

The CORS section specifies the configuration for enabling Cross-Origin Resource Sharing (CORS) for the HTTP endpoint. By default, CORS is disabled.

Default configuration:

runtime:
  cors:
    enabled: false

runtime.cors.enabled

Enables or disables CORS for the HTTP endpoint. Defaults to false.

runtime.cors.allowed_origins

A list of allowed origins for CORS requests. Defaults to ["*"], which permits all origins.

Example:

runtime:
  cors:
    enabled: true
    allowed_origins: ['https://example.com']

This configuration permits requests only from the https://example.com origin.

runtime.memory_limit

The memory_limit parameter sets a memory usage cap for the Spice runtime query engine. This limit applies only to the query engine and should be used in addition to other memory configuration options, such as duckdb_memory_limit. When memory_limit is specified, the value of runtime.temp_directory determines the directory DataFusion uses for spilling intermediate data to disk.

runtime:
  memory_limit: 4GiB

Specify the value as a size, for example 4GiB or 1024MiB.

For detailed memory information, see Memory.

runtime.temp_directory

The path to a temporary directory that Spice uses for query and acceleration operations that spill to disk. For more details, see the Managing Memory Usage documentation and the DuckDB Data Accelerator documentation.

runtime:
  temp_directory: /tmp/spice