[SPARK-31550][SQL][DOCS] Set nondeterministic configurations with general meanings in sql configuration doc

### What changes were proposed in this pull request?

```scala
spark.sql.session.timeZone

spark.sql.warehouse.dir
```
these 2 configs are nondeterministic and vary with environments

Besides, reflect code in `gen-sql-config-docs.py` via  apache#28274 (comment) and `configuration.md` via apache#28274 (comment)
### Why are the changes needed?

doc fix

### Does this PR introduce any user-facing change?

no
### How was this patch tested?

verify locally
![image](https://user-images.githubusercontent.com/8326978/80179099-5e7da200-8632-11ea-803f-d47a93151869.png)

Closes apache#28322 from yaooqinn/SPARK-31550.

Authored-by: Kent Yao <[email protected]>
Signed-off-by: HyukjinKwon <[email protected]>

Author: yaooqinn

docs/configuration.md

@@ -2624,30 +2624,31 @@ Spark subsystems.
 
 ### Spark SQL
 
+{% for static_file in site.static_files %}
+    {% if static_file.name == 'generated-runtime-sql-config-table.html' %}
+
 #### Runtime SQL Configuration
 
 Runtime SQL configurations are per-session, mutable Spark SQL configurations. They can be set with initial values by the config file
 and command-line options with `--conf/-c` prefixed, or by setting `SparkConf` that are used to create `SparkSession`.
 Also, they can be set and queried by SET commands and rest to their initial values by RESET command,
 or by `SparkSession.conf`'s setter and getter methods in runtime.
 
-{% for static_file in site.static_files %}
-    {% if static_file.name == 'generated-runtime-sql-config-table.html' %}
-        {% include_relative generated-runtime-sql-config-table.html %}
+{% include_relative generated-runtime-sql-config-table.html %}
         {% break %}
     {% endif %}
 {% endfor %}
 
+{% for static_file in site.static_files %}
+    {% if static_file.name == 'generated-static-sql-config-table.html' %}
 
 #### Static SQL Configuration
 
 Static SQL configurations are cross-session, immutable Spark SQL configurations. They can be set with final values by the config file
 and command-line options with `--conf/-c` prefixed, or by setting `SparkConf` that are used to create `SparkSession`.
 External users can query the static sql config values via `SparkSession.conf` or via set command, e.g. `SET spark.sql.extensions;`, but cannot set/unset them.
 
-{% for static_file in site.static_files %}
-    {% if static_file.name == 'generated-static-sql-config-table.html' %}
-        {% include_relative generated-static-sql-config-table.html %}
+{% include_relative generated-static-sql-config-table.html %}
         {% break %}
     {% endif %}
 {% endfor %}

sql/core/src/main/scala/org/apache/spark/sql/api/python/PythonSQLUtils.scala

@@ -40,17 +40,20 @@ private[sql] object PythonSQLUtils {
     FunctionRegistry.functionSet.flatMap(f => FunctionRegistry.builtin.lookupFunction(f)).toArray
   }
 
-  def listSQLConfigs(): Array[(String, String, String, String)] = {
+  private def listAllSQLConfigs(): Seq[(String, String, String, String)] = {
     val conf = new SQLConf()
+    // Force to build static SQL configurations
+    StaticSQLConf
+    conf.getAllDefinedConfs
+  }
+
+  def listRuntimeSQLConfigs(): Array[(String, String, String, String)] = {
     // Py4J doesn't seem to translate Seq well, so we convert to an Array.
-    conf.getAllDefinedConfs.filterNot(p => SQLConf.staticConfKeys.contains(p._1)).toArray
+    listAllSQLConfigs().filterNot(p => SQLConf.staticConfKeys.contains(p._1)).toArray
   }
 
   def listStaticSQLConfigs(): Array[(String, String, String, String)] = {
-    val conf = new SQLConf()
-    // Force to build static SQL configurations
-    StaticSQLConf
-    conf.getAllDefinedConfs.filter(p => SQLConf.staticConfKeys.contains(p._1)).toArray
+    listAllSQLConfigs().filter(p => SQLConf.staticConfKeys.contains(p._1)).toArray
   }
 
   /**

sql/core/src/test/scala/org/apache/spark/sql/api/python/PythonSQLUtilsSuite.scala

@@ -23,7 +23,7 @@ import org.apache.spark.sql.internal.{SQLConf, StaticSQLConf}
 class PythonSQLUtilsSuite extends SparkFunSuite {
 
   test("listing sql configurations contains runtime ones only") {
-    val configs = PythonSQLUtils.listSQLConfigs()
+    val configs = PythonSQLUtils.listRuntimeSQLConfigs()
 
     // static sql configurations
     assert(!configs.exists(entry => entry._1 == StaticSQLConf.SPARK_SESSION_EXTENSIONS.key),

sql/create-docs.sh

@@ -45,11 +45,8 @@ mkdir docs
 echo "Generating SQL API Markdown files."
 "$SPARK_HOME/bin/spark-submit" gen-sql-api-docs.py
 
-echo "Generating runtime SQL runtime configuration table HTML file."
-"$SPARK_HOME/bin/spark-submit" gen-sql-config-docs.py runtime
-
-echo "Generating static SQL configuration table HTML file."
-"$SPARK_HOME/bin/spark-submit" gen-sql-config-docs.py static
+echo "Generating SQL configuration table HTML file."
+"$SPARK_HOME/bin/spark-submit" gen-sql-config-docs.py
 
 echo "Generating HTML files for SQL function table and examples."
 "$SPARK_HOME/bin/spark-submit" gen-sql-functions-docs.py

sql/gen-sql-config-docs.py

@@ -17,7 +17,7 @@
 
 import os
 import re
-import sys
+
 from collections import namedtuple
 from textwrap import dedent
 
@@ -31,11 +31,11 @@
     "SQLConfEntry", ["name", "default", "description", "version"])
 
 
-def get_public_sql_configs(jvm, group):
+def get_sql_configs(jvm, group):
     if group == "static":
         config_set = jvm.org.apache.spark.sql.api.python.PythonSQLUtils.listStaticSQLConfigs()
     else:
-        config_set = jvm.org.apache.spark.sql.api.python.PythonSQLUtils.listSQLConfigs()
+        config_set = jvm.org.apache.spark.sql.api.python.PythonSQLUtils.listRuntimeSQLConfigs()
     sql_configs = [
         SQLConfEntry(
             name=_sql_config._1(),
@@ -81,7 +81,11 @@ def generate_sql_configs_table_html(sql_configs, path):
             """
         ))
         for config in sorted(sql_configs, key=lambda x: x.name):
-            if config.default == "<undefined>":
+            if config.name == "spark.sql.session.timeZone":
+                default = "(value of local timezone)"
+            elif config.name == "spark.sql.warehouse.dir":
+                default = "(value of <code>$PWD/spark-warehouse</code>)"
+            elif config.default == "<undefined>":
                 default = "(none)"
             elif config.default.startswith("<value of "):
                 referenced_config_name = value_reference_pattern.match(config.default).group(1)
@@ -119,17 +123,13 @@ def generate_sql_configs_table_html(sql_configs, path):
 
 
 if __name__ == "__main__":
-    if len(sys.argv) != 2:
-        print("Usage: ./bin/spark-submit sql/gen-sql-config-docs.py <static|runtime>")
-        sys.exit(-1)
-    else:
-        group = sys.argv[1]
-
     jvm = launch_gateway().jvm
-    sql_configs = get_public_sql_configs(jvm, group)
+    docs_root_dir = os.path.join(os.path.dirname(os.path.dirname(__file__)), "docs")
 
-    spark_root_dir = os.path.dirname(os.path.dirname(__file__))
-    sql_configs_table_path = os.path\
-        .join(spark_root_dir, "docs", "generated-" + group + "-sql-config-table.html")
+    sql_configs = get_sql_configs(jvm, "runtime")
+    sql_configs_table_path = os.path.join(docs_root_dir, "generated-runtime-sql-config-table.html")
+    generate_sql_configs_table_html(sql_configs, path=sql_configs_table_path)
 
+    sql_configs = get_sql_configs(jvm, "static")
+    sql_configs_table_path = os.path.join(docs_root_dir, "generated-static-sql-config-table.html")
     generate_sql_configs_table_html(sql_configs, path=sql_configs_table_path)