在 Terraform 的文件 db_proxy_default_target_group 只有提供 MySQL 的使用範例:resource "aws_db_proxy" "example" { name = "example" debug_logging = false engine_family = "MYSQL" idle_client_timeout = 1800 require_tls = true role_arn = aws_iam_role.example.arn vpc_security_group_ids = [aws_security_group.example.id] vpc_subnet_ids = [aws_subnet.example.id] auth { auth_scheme = "SECRETS" description = "example" iam_auth = "DISABLED" secret_arn = aws_secretsmanager_secret.example.arn } tags = { Name = "example" Key = "value" } } resource "aws_db_proxy_default_target_group" "example" { db_proxy_name = aws_db_proxy.example.name connection_pool_config { connection_borrow_timeout = 120 init_query = "SET x=1, y=2" max_connections_percent = 100 max_idle_connections_percent = 50 session_pinning_filters = ["EXCLUDE_VARIABLE_SETS"] } }
這邊 init_query 是用 “SET x=1, y=2” 當作 proxy 連上 db 的測通指令, 但是 MySQL 的 SET 指令跟 PostgreSQL 的 SET 指令用法不同, 所以直接把這個範例給 PostgreSQL 用的時候會噴錯誤:
proxy log: - [INFO] [dbConnection=1140488035] The database connection closed. Reason: An internal error occurred. db log: - ERROR: syntax error at or near "=" at character 11 - STATEMENT: SET x=1, y=2(以上來自 CloudWatch Logs, RDS 跟 RDS Proxy 都有設定送出 log 到這邊)
伸進去 PostgreSQL db 手動執行指令看看:postgres=> SET x=1, y=2; ERROR: syntax error at or near "=" LINE 1: SET x=1, y=2; ^ postgres=> SET x=1; ERROR: unrecognized configuration parameter "x" postgres=>確認是 SET 指令造成錯誤.
Google 查了幾下也是有一些回報同樣的問題, 解法幾乎都是把 init_query 拿掉, 但是這樣就少了一個 proxy 連入 db 測通 db 要有正常反應的機制.
所以找個指令替代 SET 就解決了:init_query = "VALUES (1,2)"
