Обсуждение: Binary Cursors (& Geometric Type Support)

I'm trying to port some code from C/libpq to Java & one of the things
I'm having trouble with is getting binary cursors to work.  The C code
uses a binary cursor to speed up a loop through a bunch of polygons & I
was hoping it would have the same effect with Java.  The code for a
non-binary cursor works fine, but is just taking too long.  Basically,
here's what I'm doing:

query.executeUpdate("declare my_cursor cursor for select p from
my_polygon");
ResultSet rs = query.executeQuery("fetch 1 from my_cursor");
PGpolygon p = (PGpolygon)rs.getObject("p");

When I switch the "cursor" to a "binary cursor", I get the following error:

Conversion of point failed - java.lang.NumberFormatException:
??n?gk@A?z?v A?OT&?A@A

Is there something else I have to do to get this to work or am I going
to be out of luck?  I've seen references to people successfully using
binaries cursors in earlier messages in the list -- is it just the
non-standard geometric types that are troublesome from a binary perspective?

Thanks,

Jeff Hoffmann
PropertyKey.com

Jeff,

Since the curror is returning binary data, the only method that works re
retrieve the data is getBytes().  Get Object will not work with binary
cursors.

--Barry

Jeff Hoffmann wrote:
> I'm trying to port some code from C/libpq to Java & one of the things
> I'm having trouble with is getting binary cursors to work.  The C code
> uses a binary cursor to speed up a loop through a bunch of polygons & I
> was hoping it would have the same effect with Java.  The code for a
> non-binary cursor works fine, but is just taking too long.  Basically,
> here's what I'm doing:
>
> query.executeUpdate("declare my_cursor cursor for select p from
> my_polygon");
> ResultSet rs = query.executeQuery("fetch 1 from my_cursor");
> PGpolygon p = (PGpolygon)rs.getObject("p");
>
> When I switch the "cursor" to a "binary cursor", I get the following error:
>
> Conversion of point failed - java.lang.NumberFormatException:
> ??n?gk@A?z?v A?OT&?A@A
>
> Is there something else I have to do to get this to work or am I going
> to be out of luck?  I've seen references to people successfully using
> binaries cursors in earlier messages in the list -- is it just the
> non-standard geometric types that are troublesome from a binary
> perspective?
>
> Thanks,
>
> Jeff Hoffmann
> PropertyKey.com
>
>
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Barry Lind wrote:
> Jeff,
>
> Since the curror is returning binary data, the only method that works re
> retrieve the data is getBytes().  Get Object will not work with binary
> cursors.

Gotcha.  I was hoping getObject would automagically do the type
conversion.  If only the bytes would be in the right order do use the
DataInput classes, my life would have been a little easier, but it
apparently works, so I guess I'll just take this as a learning
experience.  I guess my other question should have been "Is this the
best way to use cursors with this driver?"  I was pretty much directly
translating from a C program, but is there a better way to do it, both
for binary and regular cursors?

----
Jeff Hoffmann
PropertyKey.com

Jeff,

I use both binary and regular cursors in my code without any apparent
problems.  I am not sure what you mean by 'Is this the best way to use
cursors with this driver?'

thanks,
--Barry

Jeff Hoffmann wrote:
 > Barry Lind wrote:
 >
 >> Jeff,
 >>
 >> Since the curror is returning binary data, the only method that works
 >> re retrieve the data is getBytes().  Get Object will not work with
 >> binary cursors.
 >
 >
 > Gotcha.  I was hoping getObject would automagically do the type
 > conversion.  If only the bytes would be in the right order do use the
 > DataInput classes, my life would have been a little easier, but it
 > apparently works, so I guess I'll just take this as a learning
 > experience.  I guess my other question should have been "Is this the
 > best way to use cursors with this driver?"  I was pretty much directly
 > translating from a C program, but is there a better way to do it, both
 > for binary and regular cursors?
 >
 > ----
 > Jeff Hoffmann
 > PropertyKey.com
 >
 >