PgChannel fetch throws UnsupportedOperationException (#1602) #1568

Job	Run time
CI-CD / CI (ubuntu-latest, 25, Oracle-23) / Run tests	1m 58s
CI-CD / CI (ubuntu-latest, 25, MSSQL-2019-latest) / Run tests	1m 34s
CI-CD / CI (ubuntu-latest, 11, MySQL-5.6) / Run tests	2m 11s
CI-CD / CI (ubuntu-latest, 11, MySQL-5.7) / Run tests	2m 1s
CI-CD / CI (ubuntu-latest, 11, PostgreSQL-10) / Run tests	4m 30s
CI-CD / CI (ubuntu-latest, 11, DB2-11.5) / Run tests	6m 0s
CI-CD / CI (ubuntu-latest, 11, MSSQL-2019-latest) / Run tests	1m 32s
CI-CD / CI (ubuntu-latest, 11, PostgreSQL-9) / Run tests	4m 36s
CI-CD / CI (ubuntu-latest, 11, MSSQL-2017-latest) / Run tests	1m 40s
CI-CD / CI (ubuntu-latest, 11, MariaDB-10.4) / Run tests	2m 17s
CI-CD / CI (ubuntu-latest, 25, PostgreSQL-11) / Run tests	4m 22s
CI-CD / CI (ubuntu-latest, 11, PostgreSQL-11) / Run tests	4m 39s
CI-CD / CI (ubuntu-latest, 11, SQL-templates) / Run tests	6m 48s
CI-CD / CI (ubuntu-latest, 25, MySQL-5.7) / Run tests	2m 14s
CI-CD / CI (ubuntu-latest, 25, MariaDB-10.4) / Run tests	2m 8s
CI-CD / CI (ubuntu-latest, 11, MySQL-8.0) / Run tests	2m 26s
CI-CD / Deploy to OSSRH / Deploy (Oracle) to OSSRH	41s
CI-CD / Deploy to OSSRH / Deploy to OSSRH	1m 43s
	53m 20s

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