> ## Documentation Index
> Fetch the complete documentation index at: https://docs.kinetica.com/llms.txt
> Use this file to discover all available pages before exploring further.

# /alter/system/properties

```
URL: http://<db.host>:<db.port>/alter/system/properties
```

The [/alter/system/properties](/content/api/rest/alter_system_properties_rest)
endpoint is primarily used to simplify the testing of the system and is not
expected to be used during normal execution.  Commands are given through the
input parameter *property\_updates\_map* whose keys are commands and values are
strings representing integer values (for example '8000') or boolean values
('true' or 'false').

## Input Parameter Description

<ParamField body="property_updates_map" type="map of string to strings">
  Map containing the properties of the system to be updated. Error if empty.

  <Expandable title="property_updates_map">
    <ParamField body="concurrent_kernel_execution">
      Enables concurrent kernel execution if the value is *true* and disables it if the value is *false*.

      The supported values are:

      * true
      * false
    </ParamField>

    <ParamField body="subtask_concurrency_limit">
      Sets the maximum number of simultaneous threads allocated to a given request, on each rank. Note that thread allocation may also be limited by resource group limits and/or system load.
    </ParamField>

    <ParamField body="chunk_size">
      Sets the number of records per chunk to be used for all new tables.
    </ParamField>

    <ParamField body="chunk_column_max_memory">
      Sets the target maximum data size for each column in a chunk to be used for all new tables.
    </ParamField>

    <ParamField body="chunk_max_memory">
      Indicates the target maximum data size for all columns in a chunk to be used for all new tables.
    </ParamField>

    <ParamField body="execution_mode">
      Sets the execution\_mode for kernel executions to the specified string value. Possible values are host, device, default (engine decides) or an integer value that indicates max chunk size to exec on host.
    </ParamField>

    <ParamField body="external_files_directory">
      Sets the root directory path where external table data files are accessed from.  Path must exist on the head node.
    </ParamField>

    <ParamField body="request_timeout">
      Number of minutes after which filtering (e.g., [/filter](/content/api/rest/filter_rest)) and aggregating (e.g., [/aggregate/groupby](/content/api/rest/aggregate_groupby_rest)) queries will timeout.

      The default value is `20`. The minimum allowed value is `0`. The maximum allowed value is `1440`.
    </ParamField>

    <ParamField body="max_get_records_size">
      The maximum number of records the database will serve for a given data retrieval call.

      The default value is `20000`. The minimum allowed value is `0`. The maximum allowed value is `1000000`.
    </ParamField>

    <ParamField body="enable_audit">
      Enable or disable auditing.
    </ParamField>

    <ParamField body="audit_headers">
      Enable or disable auditing of request headers.
    </ParamField>

    <ParamField body="audit_body">
      Enable or disable auditing of request bodies.
    </ParamField>

    <ParamField body="audit_data">
      Enable or disable auditing of request data.
    </ParamField>

    <ParamField body="audit_response">
      Enable or disable auditing of response information.
    </ParamField>

    <ParamField body="shadow_agg_size">
      Size of the shadow aggregate chunk cache in bytes.

      The default value is `10000000`. The minimum allowed value is `0`. The maximum allowed value is `2147483647`.
    </ParamField>

    <ParamField body="shadow_filter_size">
      Size of the shadow filter chunk cache in bytes.

      The default value is `10000000`. The minimum allowed value is `0`. The maximum allowed value is `2147483647`.
    </ParamField>

    <ParamField body="enable_overlapped_equi_join">
      Enable overlapped-equi-join filter.

      The default value is `true`.
    </ParamField>

    <ParamField body="enable_one_step_compound_equi_join">
      Enable the one\_step compound-equi-join algorithm.

      The default value is `true`.
    </ParamField>

    <ParamField body="kafka_batch_size">
      Maximum number of records to be ingested in a single batch.

      The default value is `1000`. The minimum allowed value is `1`. The maximum allowed value is `10000000`.
    </ParamField>

    <ParamField body="kafka_poll_timeout">
      Maximum time (milliseconds) for each poll to get records from Kafka.

      The default value is `0`. The minimum allowed value is `0`. The maximum allowed value is `1000`.
    </ParamField>

    <ParamField body="kafka_wait_time">
      Maximum time (seconds) to buffer records received from Kafka before ingestion.

      The default value is `30`. The minimum allowed value is `1`. The maximum allowed value is `120`.
    </ParamField>

    <ParamField body="egress_parquet_compression">
      Parquet file compression type.

      The default value is `snappy`.

      The supported values are:

      * uncompressed
      * snappy
      * gzip
    </ParamField>

    <ParamField body="egress_single_file_max_size">
      Max file size (in MB) to allow saving to a single file. May be overridden by target limitations.

      The default value is `10000`. The minimum allowed value is `1`. The maximum allowed value is `200000`.
    </ParamField>

    <ParamField body="max_concurrent_kernels">
      Sets the max\_concurrent\_kernels value of the conf.

      The minimum allowed value is `0`. The maximum allowed value is `256`.
    </ParamField>

    <ParamField body="system_metadata_retention_period">
      Sets the system\_metadata.retention\_period value of the conf.

      The minimum allowed value is `1`.
    </ParamField>

    <ParamField body="tcs_per_tom">
      Size of the worker rank data calculation thread pool.  This is primarily used for computation-based operations such as aggregates and record retrieval.

      The minimum allowed value is `2`. The maximum allowed value is `8192`.
    </ParamField>

    <ParamField body="tps_per_tom">
      Size of the worker rank data processing thread pool.  This includes operations such as inserts, updates, and deletes on table data.  Multi-head inserts are not affected by this limit.

      The minimum allowed value is `2`. The maximum allowed value is `8192`.
    </ParamField>

    <ParamField body="background_worker_threads">
      Size of the worker rank background thread pool. This includes background operations such as watermark evictions catalog table updates.

      The minimum allowed value is `1`. The maximum allowed value is `8192`.
    </ParamField>

    <ParamField body="log_debug_job_info">
      Outputs various job-related information to the rank logs. Used for troubleshooting.
    </ParamField>

    <ParamField body="enable_thread_hang_logging">
      Log a stack trace for any thread that runs longer than a defined threshold. Used for troubleshooting.

      The default value is `true`.
    </ParamField>

    <ParamField body="ai_enable_rag">
      Enable RAG.

      The default value is `false`.
    </ParamField>

    <ParamField body="ai_api_provider">
      AI API provider type.
    </ParamField>

    <ParamField body="ai_api_url">
      AI API URL.
    </ParamField>

    <ParamField body="ai_api_key">
      AI API key.
    </ParamField>

    <ParamField body="ai_api_connection_timeout">
      AI API connection timeout in seconds.
    </ParamField>

    <ParamField body="ai_api_embeddings_model">
      AI API model name.
    </ParamField>

    <ParamField body="telm_persist_query_metrics">
      Enable or disable persisting of query metrics.
    </ParamField>

    <ParamField body="postgres_proxy_idle_connection_timeout">
      Idle connection timeout in seconds.
    </ParamField>

    <ParamField body="postgres_proxy_keep_alive">
      Enable postgres proxy keep alive.

      The default value is `false`.
    </ParamField>

    <ParamField body="kifs_directory_data_limit">
      The default maximum capacity to apply when creating a KiFS directory (bytes).

      The minimum allowed value is `-1`.
    </ParamField>

    <ParamField body="compression_codec">
      The default [compression algorithm](../../concepts/column_compression/) applied to any column without a column-level or table-level default compression specified at the time it was created.
    </ParamField>

    <ParamField body="disk_auto_optimize_timeout">
      Time interval in seconds after which the database will apply optimizations/transformations to persisted data, such as compression.

      The minimum allowed value is `0`.
    </ParamField>

    <ParamField body="ha_consumer_replay_offset">
      Initializes HA replay from the given timestamp (as milliseconds since unix epoch).

      The minimum allowed value is `-1`.
    </ParamField>

    <ParamField body="admin_access_only">
      Restricts access to system admin users only.

      The default value is `false`.
    </ParamField>
  </Expandable>
</ParamField>

<ParamField body="options" type="map of string to strings">
  Optional parameters.

  The default value is an empty map ( \{} ).

  <Expandable title="options">
    <ParamField body="evict_to_cold">
      If *true* and evict\_columns is specified, the given objects will be evicted to cold storage (if such a tier exists).

      The supported values are:

      * true
      * false
    </ParamField>

    <ParamField body="persist">
      If *true* the system configuration will be written to disk upon successful application of this request. This will commit the changes from this request and any additional in-memory modifications.

      The default value is `true`.

      The supported values are:

      * true
      * false
    </ParamField>
  </Expandable>
</ParamField>

## Output Parameter Description

The Kinetica server embeds the endpoint response inside a standard response structure which contains status information and the actual response to the query.  Here is a description of the various fields of the wrapper:

<ResponseField name="status" type="String">
  'OK' or 'ERROR'
</ResponseField>

<ResponseField name="message" type="String">
  Empty if success or an error message
</ResponseField>

<ResponseField name="data_type" type="String">
  'alter\_system\_properties\_response' or 'none' in case of an error
</ResponseField>

<ResponseField name="data" type="String">
  Empty string
</ResponseField>

<ResponseField name="data_str" type="JSON or String">
  This embedded JSON represents the result of the /alter/system/properties endpoint:

  <Expandable title="data_str">
    <ResponseField name="updated_properties_map" type="map of string to strings">
      Map of values updated; for speed tests, a map of values measured to the measurement.
    </ResponseField>

    <ResponseField name="info" type="map of string to strings">
      Additional information.
    </ResponseField>
  </Expandable>

  Empty string in case of an error.
</ResponseField>