Arcsde version: 9.1
Database: Oracle 10gR2
Beginning with ArcSDE 9.2 geodatabases, the spatial index is calculated for you when you create a new dataset and provide a coordinate system in ArcGIS Desktop. You shouldn't need to tune such spatial indexes. However, if you are using an older release of ArcSDE such as 9.1, you can follow the steps below to tune the index.
1. Check the spatial index
C:\ArcSDE91>sdelayer -o si_stats -l my_layer,geometry -i 5151 -s sde_server -u usera -p pwd
ArcSDE 9.1 Oracle10g Build 391 Tue Oct 24 11:44:47 PDT 2006
Layer Administration Utility
-----------------------------------------------------
Layer 1606 Spatial Index Statistics:
Level 1, Grid Size 50000
|-------------------------------------------------------------------|
| Grid Records: 2680 |
| Feature Records: 174 |
| Grids/Feature Ratio: 15.40 |
| Avg. Features per Grid: 4.73 |
| Max. Features per Grid: 17 |
| % of Features Wholly Inside 1 Grid: 1.72 |
|-------------------------------------------------------------------|
| Spatial Index Record Count By Group |
| Grids: <=4 >4 >10 >25 >50 >100 >250 >500 |
|---------- ------ ------ ------ ------ ------ ------ ------ ------ |
| Features: 51 123 77 30 10 0 0 0 |
| % Total: 29% 71% 44% 17% 6% 0% 0% 0%|
|-------------------------------------------------------------------|
2. Use sdelayer –o load_only_io to drop the spatial index. Switching the feature class to load-only mode drops the spatial index. While the feature class is in load-only mode, no spatial queries or data loading is allowed on this layer.
C:\ArcSDE91>sdelayer -o load_only_io -l my_layer,geometry -i 5151 -s sde_server -u usera -p pwd
ArcSDE 9.1 Oracle10g Build 391 Tue Oct 24 11:44:47 PDT 2006
Layer Administration Utility
-----------------------------------------------------
Layer is now in LOAD-ONLY I/O mode.
3. Use sdelayer –o alter –g n,n,n to specify new grid sizes. Specify 0 for the second or third grid size if not used.
C:\ArcSDE91>sdelayer -o alter -l my_layer,geometry -g 150000,0,0 -i 5151 -s sde_server -u usera -p pwd
ArcSDE 9.1 Oracle10g Build 391 Tue Oct 24 11:44:47 PDT 2006
Layer Administration Utility
-----------------------------------------------------
Change spatial index from SPIDX_GRID,50000
to SPIDX_GRID,150000
Are you sure? (Y/N): y
Successfully Modified the Layer
Successfully changed spatial index parameters and rebuild as needed
4. Use sdelayer –o normal_io to rebuild the spatial index and make the layer accessible again.
C:\ArcSDE91>sdelayer -o normal_io -l my_layer,geometry -i 5151 -s sde_server -u usera -p pwd
ArcSDE 9.1 Oracle10g Build 391 Tue Oct 24 11:44:47 PDT 2006
Layer Administration Utility
-----------------------------------------------------
Layer is now in NORMAL I/O mode.
5. Check the spatial index
C:\ArcSDE91>sdelayer -o si_stats -l my_layer,geometry -i 5151 -s sde_server -u usera -p pwd
ArcSDE 9.1 Oracle10g Build 391 Tue Oct 24 11:44:47 PDT 2006
Layer Administration Utility
-----------------------------------------------------
Layer 1606 Spatial Index Statistics:
Level 1, Grid Size 150000
|-------------------------------------------------------------------|
| Grid Records: 675 |
| Feature Records: 174 |
| Grids/Feature Ratio: 3.88 |
| Avg. Features per Grid: 8.44 |
| Max. Features per Grid: 32 |
| % of Features Wholly Inside 1 Grid: 22.41 |
|-------------------------------------------------------------------|
| Spatial Index Record Count By Group |
| Grids: <=4 >4 >10 >25 >50 >100 >250 >500 |
|---------- ------ ------ ------ ------ ------ ------ ------ ------ |
| Features: 134 40 10 0 0 0 0 0 |
| % Total: 77% 23% 6% 0% 0% 0% 0% 0%|
|-------------------------------------------------------------------|
6. Repeat step 2 to 5 until satisfied.
C:\ArcSDE91>sdelayer -o si_stats -l my_layer,geometry -i 5151 -s sde_server -u usera -p pwd
ArcSDE 9.1 Oracle10g Build 391 Tue Oct 24 11:44:47 PDT 2006
Layer Administration Utility
-----------------------------------------------------
Layer 1606 Spatial Index Statistics:
Level 1, Grid Size 425000
|-------------------------------------------------------------------|
| Grid Records: 287 |
| Feature Records: 174 |
| Grids/Feature Ratio: 1.65 |
| Avg. Features per Grid: 17.94 |
| Max. Features per Grid: 77 |
| % of Features Wholly Inside 1 Grid: 58.05 |
|-------------------------------------------------------------------|
| Spatial Index Record Count By Group |
| Grids: <=4 >4 >10 >25 >50 >100 >250 >500 |
|---------- ------ ------ ------ ------ ------ ------ ------ ------ |
| Features: 174 0 0 0 0 0 0 0 |
| % Total: 100% 0% 0% 0% 0% 0% 0% 0%|
|-------------------------------------------------------------------|
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