On Fri, 2024-03-29 at 10:05 +0800, James Pang wrote: > PGV14, client use PGJDBC driver and prepared statements, when a table > "alter table alter column type ..." changes done, a lot of JDBC clients > got this error "cached plan must not change result type". when a JDBC > client got this error first time after the DDL schema change, JDBC driver > will clear this caching-plan and following same SQL statement got parsing > again and new cached plan right? Not sure; what do you observe? Anyway, this is a known problem: https://jdbc.postgresql.org/documentation/server-prepare/#ddl > How to avoid this issue when DDL schema changes ? Don't use server-side prepared statements: https://jdbc.postgresql.org/documentation/server-prepare/#deactivation You'll lose some performance though. Questions like this had better be asked on the pgsql-jdbc list. Yours, Laurenz Albe