Add Presto C++ config properties doc

presto-docs/src/main/sphinx/presto-cpp.rst

@@ -9,6 +9,7 @@ Note: Presto C++ is in active development. See :doc:`Limitations </presto_cpp/li
 
     presto_cpp/features
     presto_cpp/limitations
+    presto_cpp/properties
 
 Overview
 ========

presto-docs/src/main/sphinx/presto_cpp/properties.rst

@@ -0,0 +1,147 @@
+===============================
+Presto C++ Properties Reference
+===============================
+
+This section describes Presto C++ configuration properties.
+
+The following is not a complete list of all configuration and
+session properties, and does not include any connector-specific
+catalog configuration properties. For information on catalog 
+configuration properties, see :doc:`Connectors </connector/>`.
+
+.. contents::
+    :local:
+    :backlinks: none
+    :depth: 1
+
+Coordinator Properties
+----------------------
+
+Set the following configuration properties for the Presto coordinator exactly 
+as they are shown in this code block to enable the Presto coordinator's use of 
+Presto C++ workers. 
+
+.. code-block:: none
+
+    native-execution-enabled=true
+    optimizer.optimize-hash-generation=false
+    regex-library=RE2J
+    use-alternative-function-signatures=true
+    experimental.table-writer-merge-operator-enabled=false
+
+These Presto coordinator configuration properties are described here, in 
+alphabetical order. 
+
+``experimental.table-writer-merge-operator-enabled``
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+* **Type:** ``boolean``
+* **Default value:** ``true``
+
+  Merge TableWriter output before sending to TableFinishOperator. This property must be set to 
+  ``false``. 
+
+``native-execution-enabled``
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+* **Type:** ``boolean``
+* **Default value:** ``false``
+
+  This property is required when running Presto C++ workers because of 
+  underlying differences in behavior from Java workers.
+
+``optimizer.optimize-hash-generation``
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+* **Type:** ``boolean``
+* **Default value:** ``true``
+
+  Set this property to ``false`` when running Presto C++ workers.  
+  Velox does not support optimized hash generation, instead using a HashTable 
+  with adaptive runtime optimizations that does not use extra hash fields. 
+
+``regex-library``
+^^^^^^^^^^^^^^^^^
+
+* **Type:** ``type``
+* **Allowed values:** ``RE2J``
+* **Default value:** ``JONI``
+
+  Only `RE2J <https://github.com/google/re2j>`_ is currently supported by Velox.
+
+``use-alternative-function-signatures``
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+* **Type:** ``boolean``
+* **Default value:** ``false``
+
+  Some aggregation functions use generic intermediate types which are 
+  not compatible with Velox aggregation function intermediate types. One  
+  example function is ``approx_distinct``, whose intermediate type is 
+  ``VARBINARY``. 
+  This property provides function signatures for built-in aggregation 
+  functions which are compatible with Velox.
+
+Worker Properties
+-----------------
+
+The configuration properties of Presto C++ workers are described here, in alphabetical order. 
+
+``async-data-cache-enabled``
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+* **Type:** ``boolean``
+* **Default value:** ``true``
+
+  In-memory cache.
+
+``query.max-memory-per-node``
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+* **Type:** ``integer``
+* **Default value:** ``4GB``
+
+  Max memory usage for each query.
+
+``query-memory-gb``
+^^^^^^^^^^^^^^^^^^^
+
+* **Type:** ``integer``
+* **Default value:** ``38``
+
+  The total memory capacity that can be used across all query executions. 
+  Memory for system usage such as disk spilling and cache prefetch which 
+  are not counted in query memory usage.
+
+``query-reserved-memory-gb``
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+* **Type:** ``integer``
+* **Default value:** ``4``
+
+  Specifies the amount of query memory capacity reserved 
+  to ensure that each query has the minimal memory capacity to run. A query can 
+  only allocate from the reserved query memory if its current capacity is less 
+  than the minimal memory capacity as specified by 
+  ``memory-pool-reserved-capacity``. 
+
+  The exceeding capacity must allocate from the non-reserved query memory.
+
+``system-memory-gb``
+^^^^^^^^^^^^^^^^^^^^
+
+* **Type:** ``integer``
+* **Default value:** ``40``
+
+  Memory allocation limit enforced via internal memory allocator. 
+
+  Set ``system-memory-gb`` to the available machine memory of the deployment.
+
+``task.max-drivers-per-task``
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+* **Type:** ``integer``
+* **Default value:** ``number of hardware CPUs``
+
+  Number of drivers to use per task. Defaults to hardware CPUs.
+