Re: JDBC: ERROR: portal "C_2" does not exist

Hi Blake

On Fri, 11 Mar 2022 at 14:04, Sehrope Sarkuni <sehrope(at)jackdb(dot)com> wrote:

> When auto commit is diabled and using a non-zero fetch size, the pgjdbc
> driver creates a portal to read the query results from the server in chunks
> of fetch size. The portals have a string identifier and the driver
> generates them sequentially per connection with a "C_" prefix, so "C_1", "
> C_2", "C_3", ... etc.
>
> As you read results via ResultSet.next(), the driver checks if it has the
> next row already buffered. If not, it reads from the named portal to
> retrieve the next chunk of fetchSize quantity of rows.
>
> A fetch size of 50 and the error happening at row 51 likely means that
> something either closed the portal or the connection itself is not correct.
>
> Are you using a connection pool like pgbouncer in between your Java
> application and the database server?
>
> If so, the connection pooler must be transaction aware to ensure that the
> same connection is used throughout the entire transaction.
>

Actually the recommendation for pgbouncer and I presume other poolers is to
turn off prepared statements
Disabling prepared statements in JDBC

The proper way to do it for JDBC is adding the prepareThreshold=0 parameter
to the connection string.

Dave

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