PostgreSQL は、プロセスを起動してから SQL クエリ・外部入力を受け付けるようになるまで若干のタイムラグが有ります。特に Docker コンテナで起動した場合、自分の環境では5秒程度待つことになります。 The files belonging to this database system will be owned by user "postgres". This user must also own the server process. The database cluster will be initialized with locale "en_US.utf8". The default database encoding has accordingly been set to "UTF8". The default text search configuration
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