Postgres-XL集羣ERROR ：Failed to get pooled connections緣由說明

1. 集羣說明

6臺服務器。其中1臺（rt67-1）運行GTM，其他5臺均運行1個GTM_PROXY、1個Coordinator node、3個Data node。每一個服務器鏈接到3組網絡中，每一個Data node分別處在一組網絡中。

1. 問題描述

   在鏈接入庫併發數較高時，報錯：

   ERROR: Failed to get pooled connections

   HINT: This may happen because one or more nodes are currently unreachable, either because of node or network failure.

        Its also possible that the target node may have hit the connection limit or the pooler is configured with low connections.

        Please check if all nodes are running fine and also review max_connections and max_pool_size configuration parameters

2. 分析過程

   檢查了網絡、防火牆、max_connections、max_pool_size均沒有問題。無心中發現data node的參數文件中gtm_host設置爲rt67-1，好像哪裏不對。因而在官網上查詢對該參數的定義。

3. 官方文檔對gtm_host的說明

Configuring Datanodes

Configuring Coordinators

gtm_proxy

 

Postgres-XL Specific Parameters

1. 問題修正

   經過對該參數定義的解讀，發現多是data node中該參數設置不當引發的錯誤。因而將該參數調整爲當前服務器的gtm_proxy的IP和端口。再測試，問題得以修正。

2. 其它

gtm_connect_retry_interval (integer)

Specifies how long in seconds GTM-Proxy waits between each retry to connect to GTM when communication error with GTM is detected. Default value is 60. Refer to gtm_connect_retry_count and gtm_connect_retry_idle.