Re: cached plan must not change result type

Thanks Laurenz,  forwarded to pgjdbc,  we want to understand why JDBC failed to reexecute the SQL instead of throw error out. Like this document https://jdbc.postgresql.org/documentation/server-prepare/#re-execution-of-failed-statements .

Thanks,

James 

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