This topic describes the ST_Estimated3DExtent function. This function uses the 3D index or 3D statistical histogram information to estimate the smallest outer envelope of the whole table in which the sfmesh object locates.
Syntax
box3d ST_Estimated3DExtent(cstring schema_name, cstring table_name, cstring mesh_column_name, boolean parent_only);
box3d ST_Estimated3DExtent(cstring schema_name, cstring table_name, cstring mesh_column_name);
box3d ST_Estimated3DExtent(cstring table_name, cstring mesh_column_name);Parameters
| Parameter | Description |
|---|---|
| schema_name | The schema of the table. |
| table_name | The name of the table. |
| mesh_column_name | The name of the sfmesh field. |
| parent_only | If the table is a partitioned table, this parameter specifies whether to estimate the smallest outer envelop only for the parent table. |
Description
This function returns the smallest outer envelope box3d. To successfully run this
function, you must create a 3D index for the sfmesh field or perform the analyze operation on the sfmesh field to generate statistical information.
Examples
- Example 1:
select st_estimated3dextent('public','test_table','the_mesh',false); st_estimatedextent ------------------------------------------------------------------------------------------- BOX3D(171528.71875 220124.125 -1277.06030273438,336328.71875 300186.96875 35850.00390625) (1 row) - Example 2:
select st_estimated3dextent('test_table','the_mesh',false); st_estimatedextent ------------------------------------------------------------------------------------------- BOX3D(171528.71875 220124.125 -1277.06030273438,336328.71875 300186.96875 35850.00390625) (1 row) - Example 3:
select st_estimated3dextent('mesh_gist_test','the_mesh'); st_estimated3dextent ------------------------------------------------------------------------------------------- BOX3D(171528.71875 220124.125 -1277.06030273438,336328.71875 300186.96875 35850.00390625) (1 row)