Spatial query in a distributed environment

Question

We want to compare two spatial tables.
We have (at present identical) tables on two computers GEOSRV0 and NB25.
On both we have Oracle 10.1.0.2. GEOSRV0 has the WINDOWS 2000 operating system installed, on NB25 there is WINDOWS XP Professional.
The table is EZG:
GEOMETRY MDSYS.SDO_GEOMETRY
GEOMETRY_SK VARCHAR2(15)
EZG_NR NOT NULL NUMBER
FLAECHE FLOAT(126)
The primary key is EZG_NR.
There is a private database link for the user WLKREP on NB25 to user WLKREP on GEOSRV0.
The USER_SDO_GEOM_METADATA are the same on both machines (same SRID, same DIMINFO).
The following query – we check, if for each record on NB25 is a record on GEOSRV0 - works normally:
SQL> select ezg_nr from
2 ezg a where not exists
3 (select 1 from wlkrep.ezg@wlk where ezg_nr=a.ezg_nr);
no rows selected
This is correct.
We can read the geometry on the remote database:
SQL> select * from wlkrep.ezg@wlk where rownum=1;
GEOMETRY(SDO_GTYPE, SDO_SRID, SDO_POINT(X, Y, Z), SDO_ELEM_INFO, SDO_ORDINATES)
GEOMETRY_SK EZG_NR FLAECHE
SDO_GEOMETRY(3003, 1040001, NULL, SDO_ELEM_INFO_ARRAY(1, 1003, 1), SDO_ORDINATE_ARRAY(182285.489, 405672.889, 0, 182248.701, 405644.889, 0, 182241.984, 405639.771, 0, 182171.753, 405538.805, 0, 182130.953, 405498.016, 0, 181971.1, 405274.91
6, 0, 182223.796, 405176.609, 0, 182292.701, 405204.37, 0, 182439.028, 405451.66
, 0, 182573.506, 405628.153, 0, 182643.64, 405726.59, 0, 182718.945, 405764.608,
0, 182780.371, 405805.57, 0, 182862.191, 405843.931, 0, 182966.69, 405933.13, 0
, 183131.065, 406064.852, 0, 183205.098, 406160.637, 0, 183231.535, 406220.959,
0, 183266.473, 406265.415, 0, 183308.669, 406303.524, 0, 183295.305, 406364.696,
0, 183204.283, 406331.35, 0, 183161.835, 406299.691, 0, 183134.554, 406243.403,
GEOMETRY(SDO_GTYPE, SDO_SRID, SDO_POINT(X, Y, Z), SDO_ELEM_INFO, SDO_ORDINATES)
GEOMETRY_SK EZG_NR FLAECHE
0, 183080.454, 406171.548, 0, 183027.376, 406123.698, 0, 182914.558, 406039.291
, 0, 182770.335, 405973.138, 0, 182593.691, 405886.413, 0, 182443.506, 405795.85
2, 0, 182343.293, 405713.991, 0, 182285.489, 405672.889, 0))
13 304906.065
Now we want to compare the geometry and get
SQL> select a.ezg_nr from
2 wlkrep.ezg@wlk b, ezg a where a.ezg_nr=b.ezg_nr and
3 sdo_equal(a.geometry,b.geometry) != 'TRUE';
select a.ezg_nr from
ERROR at line 1:
ORA-03113: end-of-file on communication channel
Only comparing two elements gives the same result
SQL> select a.ezg_nr from
2 wlkrep.ezg@wlk b, ezg a where a.ezg_nr=640 and
3 b.ezg_nr = 640 and
4 sdo_equal(a.geometry,b.geometry) = 'TRUE';
select a.ezg_nr from
ERROR at line 1:
ORA-03113: end-of-file on communication channel
Even if we query a non existing element
select count(*) from ezg where ezg_nr=99999;
COUNT(*)
0
SQL> select a.ezg_nr from
2 wlkrep.ezg@wlk b, ezg a where a.ezg_nr=99999 and
3 b.ezg_nr = 99999 and
4 sdo_equal(a.geometry,b.geometry) = 'TRUE';
select a.ezg_nr from
ERROR at line 1:
ORA-03113: end-of-file on communication channel
Is this a bug or is a distributed spatial query not supported?
The following statement works:
SQL> select a.ezg_nr from
2 wlkrep.ezg@wlk a where not exists
3 (select 1 from ezg b where
4 b.ezg_nr=a.ezg_nr and
5 sdo_equal(b.geometry,a.geometry)='TRUE');
no rows selected
Regards
Karl

Answer 1

Actually, I have filed a TAR to Oracle on this. I also spoke to Steve Muench about it at OracleWorld, briefly. As of today, I'm trying to add to DataScroller.java to make it implement java.io.Serializable (with no luck...maybe someone can comment on what I'm doing wrong).
Here's what I have done so far.
Changed DataScroller.java (located in bc4jhtmlsrc.zip) to the following:
public class DataScroller implements java.io.Serializable
I added the following members per the docs on java.io.Serializable
private void writeObject(java.io.ObjectOutputStream out)
throws IOException
// really don't need to save state. Next call will recompute what's necessary
private void readObject(java.io.ObjectInputStream in)
throws IOException, ClassNotFoundException
// really don't need to load state. Next call will recompute what's necessary
I then used jar xvf to "unjar" datatags.jar, replaced DataScroller.class with my version and used
jar cv0Mf datatags.jar META-INF/* oracle/*
to recreate the datatags.jar. My file is not 100% the exact same as their file, but it looks to be right to me. I ended up doing it this way because the oracle\ord\* classes are not in the bc4jhtmlsrc.zip, only in the jar file and felt this was the "safest" way to include the correct contents of the file.
HOWEVER -- I'm sorry to say that I've then tried to run my app and get the same issue.
Thanks,
Jeff