On 26-11-2021 10:10, Dmitry Yemanov wrote:
Mark et al,
Yes, I think that is perfectly acceptable for an initial version.
Scrollable cursors are a bit of an oddity anyway, but having
scrollable cursors in embedded access, but not in remote access is
IMHO less acceptable than bad performance. As long as the performance
behaviour is clearly documented, people can make the decision if the
bad performance is worth the utility of scrollable cursors for
themselves.
I've just committed network support for scrollable cursors to master.
Prefetch logic is supported for NEXT/PRIOR navigations. Protocol changes
are documented here:
Is there a way to determine at which row the cursor is currently
positioned? JDBC has the ResultSet.getRow()[1] method which is
documented as: "Retrieves the current row number. The first row is
number 1, the second number 2, and so on."
This is not problematic when using first, next, prior, relative or
absolute, but once you do fetch_last, you don't know the row number
until you do a first or absolute.
The usefulness of this method is limited, but sometimes it is abused by
people wanting to know how many rows there are in a result set (by
requesting the last row), and if I can't fulfill this requirement, I
need to at least document this.
[1]:
https://docs.oracle.com/en/java/javase/17/docs/api/java.sql/java/sql/ResultSet.html#getRow()
--
Mark Rotteveel
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