Document connection classes and settings.

Signed-off-by: dblock <[email protected]>

USER_GUIDE.md

@@ -154,6 +154,7 @@ print(response)
 - [Point in Time](guides/point_in_time.md)
 - [Using a Proxy](guides/proxy.md)
 - [Index Templates](guides/index_template.md)
+- [Connection Classes](guides/connection_classes.md)
 
 ## Plugins
 

guides/auth.md

@@ -113,7 +113,6 @@ client = OpenSearch(
     ['htps://...'],
     use_ssl=True,
     verify_certs=True,
-    connection_class=RequestsHttpConnection,
     http_auth=HTTPKerberosAuth(mutual_authentication=OPTIONAL)
 )
 

guides/connection_classes.md

@@ -0,0 +1,81 @@
+- [Connection Classes](#connection-classes)
+  - [Selecting a Connection Class](#selecting-a-connection-class)
+    - [Urllib3HttpConnection](#urllib3httpconnection)
+    - [RequestsHttpConnection](#requestshttpconnection)
+    - [AsyncHttpConnection](#asynchttpconnection)
+  - [Connection Pooling](#connection-pooling)
+
+# Connection Classes
+
+The OpenSearch Python synchrnous client supports both the `Urllib3HttpConnection` connection class (default) from the [urllib3](https://pypi.org/project/urllib3/) library, and `RequestsHttpConnection` from the [requests](https://pypi.org/project/requests/) library. We recommend you use the default, unless your application is standardized on `requests`. 
+
+The faster, asynchronous client, implements a class called `AsyncHttpConnection`, which uses [aiohttp](https://pypi.org/project/aiohttp/).
+
+## Selecting a Connection Class
+
+### Urllib3HttpConnection
+
+```python
+from opensearchpy import OpenSearch, Urllib3HttpConnection
+
+client = OpenSearch(
+    hosts = [{'host': 'localhost', 'port': 9200}],
+    http_auth = ('admin', 'admin'),
+    use_ssl = True,
+    verify_certs = False,
+    ssl_show_warn = False,
+    connection_class = Urllib3HttpConnection
+)
+```
+
+### RequestsHttpConnection
+
+```python
+from opensearchpy import OpenSearch, RequestsHttpConnection
+
+client = OpenSearch(
+    hosts = [{'host': 'localhost', 'port': 9200}],
+    http_auth = ('admin', 'admin'),
+    use_ssl = True,
+    verify_certs = False,
+    ssl_show_warn = False,
+    connection_class = RequestsHttpConnection
+)
+```
+
+### AsyncHttpConnection
+
+```python
+from opensearchpy import AsyncOpenSearch, AsyncHttpConnection
+
+async def main():
+    client = AsyncOpenSearch(
+        hosts = [{'host': 'localhost', 'port': 9200}],
+        http_auth = ('admin', 'admin'),
+        use_ssl = True,
+        verify_certs = False,
+        ssl_show_warn = False,
+        connection_class = AsyncHttpConnection
+    )
+```
+
+## Connection Pooling
+
+The OpenSearch Python client has a connection pool for each `host` value specified during initialization, and a connection pool for HTTP connections to each host implemented in the underlying HTTP libraries. You can adjust the max size of the latter connection pool with `pool_maxsize`. 
+
+If you don't set this value, each connection library implementation will provide its default, which is typically `10`. Changing the pool size may improve performance in some multithreaded scenarios.
+
+The following example sets the number of connections in the connection pool to 12.
+
+```python
+from opensearchpy import OpenSearch
+
+client = OpenSearch(
+    hosts = [{'host': 'localhost', 'port': 9200}],
+    http_auth = ('admin', 'admin'),
+    use_ssl = True,
+    verify_certs = False,
+    ssl_show_warn = False,
+    pool_maxsize = 12,
+)
+```

guides/proxy.md

@@ -13,7 +13,6 @@ OpenSearch(
     hosts=["htps://..."],
     use_ssl=True,
     verify_certs=True,
-    connection_class=RequestsHttpConnection,
     trust_env=True,
 )
 ```