# Rally logs shows max\_connections=1, but the doc said at least 256? And what does max\_connections really do? it seems es client didn't support this param **URL:** \ **Category:** Elasticsearch\ **Tags:** rally\ **Created:** [June 3, 2021, 3:31am UTC](https://discuss.elastic.co/t/rally-logs-shows-max-connections-1-but-the-doc-said-at-least-256-and-what-does-max-connections-really-do-it-seems-es-client-didnt-support-this-param/274818 "2021-06-03T03:31:12Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![GITnewfish](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/gitnewfish/32/87303_2.png) [@GITnewfish](https://discuss.elastic.co/u/GITnewfish)\ **Post date:** [June 3, 2021, 3:31am UTC](https://discuss.elastic.co/t/rally-logs-shows-max-connections-1-but-the-doc-said-at-least-256-and-what-does-max-connections-really-do-it-seems-es-client-didnt-support-this-param/274818/1 "2021-06-03T03:31:13Z")
as the title said, I'm confused what does max\_connections really do? it seems es client didn't support this param. the rally command: esrally race --pipeline=benchmark-only --track=test --target-hosts=$target\_hosts --challenge=append-no-conflicts --track-params="bulk\_size:10000,bulk\_indexing\_clients:32,number\_of\_replicas:1,number\_of\_shards:1" --client-options="timeout:180" the rally log: ![image](https://us1.discourse-cdn.com/elastic/original/3X/4/9/495fa41fdd1bdcb57f5de646059a2d26dc359eca.png) the doc said: ![image](https://us1.discourse-cdn.com/elastic/original/3X/d/1/d1ed7fb2a263eae81b29db8eb73ff5a1473e18f6.png) es didn't exposed this parameter to the user > [@How to control maximum number of client connections to ES instance](https://discuss.elastic.co/t/how-to-control-maximum-number-of-client-connections-to-es-instance/21048): > > Hi: Is there a configuration variable that I could set on an ES instance that can control the maximum number of client connections ? What is the default limit on the max. connections ? and how can I change it ? If I have a SPARK application that is retrieving results from an ES instance, I am running into a NoNodeAvailable Exception. But if I reduce the number of processes, then the errors seems to go away. all help is appreciated. Thanks Ramdev -- You received this message because yo… so what does the rally with this param do? ---
**Author:** ![Bradley\_Deam](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/bradley_deam/32/52991_2.png) [@Bradley\_Deam](https://discuss.elastic.co/u/Bradley_Deam)\ **Post date:** [June 4, 2021, 12:08am UTC](https://discuss.elastic.co/t/rally-logs-shows-max-connections-1-but-the-doc-said-at-least-256-and-what-does-max-connections-really-do-it-seems-es-client-didnt-support-this-param/274818/2 "2021-06-04T00:08:57Z")
Hi @GITnewfish ! > as the title said, I'm confused what does max\_connections really do? it seems es client didn't support this param. > ... > so what does the rally with this param do? This particular setting (`max_connections`) is in reference to the maximum number of connections that can be left open per client. This is done for performance reasons e.g. reuse of existing connections, and to preventing client side bottlenecks. > es didn't exposed this parameter to the user `max_connections` is a Rally specific setting, though it's equivalent Elasticsearch Python client configuration setting (`maxsize`) can be found here: [Using Asyncio with Elasticsearch — Python Elasticsearch client 8.11.0 documentation](https://elasticsearch-py.readthedocs.io/en/latest/async.html#aiohttpconnection). Keep in mind that this setting is at the _client_ side, Elasticsearch nodes themselves (server side) do not have a setting available to limit client connections besides the usual Operating System level configurations. ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [July 2, 2021, 12:09am UTC](https://discuss.elastic.co/t/rally-logs-shows-max-connections-1-but-the-doc-said-at-least-256-and-what-does-max-connections-really-do-it-seems-es-client-didnt-support-this-param/274818/3 "2021-07-02T00:09:39Z")
This topic was automatically closed 28 days after the last reply. New replies are no longer allowed.