Re: ECPG support for PQsetChunkedRowsMode()

Tim Fors wrote:

> Note that ECPG supports using a C array as a host variable, and in
> that case there's a bulk transfer of rows from the client to the
> server, so performance is much better than getting the rows one at a
> time using a cursor. However, AFAIK this is not standard coding
> practice - one expects to be able to use the cursor to FETCH one
> row at a time, but still offer good performance.

It's just a preprocessor. If the C code has EXEC SQL FETCH NEXT, it's
going to emit code sending a FETCH NEXT [1] SQL statement.

But aside from the arrays you mention, it allows retrieving several
rows at a time through a cursor, so the client-side can still reduce
the round-trips to the server. See this example in [2]:
EXEC SQL FETCH 3 FROM mycursor INTO DESCRIPTOR mysqlda;

[1]: https://www.postgresql.org/docs/current/sql-fetch.html

[2]: https://www.postgresql.org/docs/current/ecpg-descriptors.html

Best regards,
--
Daniel Vérité
https://postgresql.verite.pro/