Jmeter test interface of PostgreSql, but often happens "idle in transaction"

I use Jmeter test the springboot system with druid pool, there are almost 50 interfaces need to be tested. When tested a half (Serial execution), the Jmeter was blocked, then I use sql


This is a companion discussion topic for the original entry at https://stackoverflow.com/questions/74498637/jmeter-test-interface-of-postgresql-but-often-happens-idle-in-transaction