ArcSDE sets the dbtune parameter to store blob Columns

Abstract:The storage parameters in the dbtune table control how to create tables and indexes in Oracle. Some storage parameters define the data types used when creating a table.

The storage parameters in the dbtune table control how to create tables and indexes in Oracle. Some storage parameters define the data types used when creating a table.
The dbtune storage parameters of ArcSDE, such as geometry_storage, raster_storage, and attribute_binary, define the Oracle data types used to store ArcSDE data.
Note that the parameter raster_binary_type is replaced by raster_storage starting from ArcSDE 9.2.
Geometry_storage controls the storage of Vector Data (featureclass. Raster_storage controls the storage of raster dataset, raster catalog, or raster attribute. Attribute_binary controls the storage of other binary data (non-vector and raster data ).
Use blob columns in ArcSDE to store data. The dbtune keyword is set as follows:
Geometry_storage sdelob
Raster_storage blob
Attribute_binary blob
We recommend that you use the following settings to store vector and raster data:
1) The in-row storage option is always used. In GIS, most of the element data is smaller than 3,964 bytes. Use the in-row storage option to achieve better performance.
2) use cache for frequently-read data );
3) If BLOB data is often inserted or deleted rather than updated frequently by ArcSDE, set the pct_version parameter to 0, telling Oracle that data of earlier versions does not need to be maintained on the lob segment.
4) The size of Chuck should not be smaller than 8 K. Tests show that 8 K is the most suitable data block for storing GIS data.
The following is an example of setting the raster_storage parameter.
Raster_storage "blob"
Blk_storage "pctfree 0 initrans 4 tablespace raster
Lob (block_data) store
(Tablespace raster_lob_segment
Cache pctversion 0 )"
Raster_storage "blob" indicates using blob to store raster data. If the block pixel data of the raster is smaller than 3,965 bytes, the data is stored in the block_data column of the raster tablespace. If the value is greater than 3,964 bytes, it is stored in the lob segment of the raster_lob_segment tablespace. The lob index is used only when the number of chunks exceeds 12.
The following example shows how to set the geometry_storage parameter.
Geometry_storage "sdelob"
F_storage "pctfree 0 initrans 4 tablespace Vector
Lob (points) store
(Tablespace vector_lob_segment
Cache pctversion 0 )"
Geometry_storage "sdelob" indicates storing Vector Data in blob mode. If the binary data of the element is less than 3,965 bytes, it is stored in the points column of the vector tablespace. If this value is exceeded, it is stored in the lob segment of the vector_lob_segment tablespace.
The following is an example of setting the attribute_binary "blob" parameter.
Attribute_binary "blob"
B _storage "pctfree 0 initrans 4 tablespace bizztabs
Lob (document) store
(Tablespace bizz_lob_segment
Cache pctversion 0 )"
Attribute_binary "blob" indicates storing attribute data (non-vector and raster data) in blob mode ). If the binary data of Table B is less than 3,965 bytes, it is stored in the document column of the bizztabs tablespace. If this size is exceeded, it is stored in the lob segment of the bizz_lob_segment tablespace. If the document column is not displayed when table B is created, Oracle reports the following error:
ORA-00904: "document": Invalid identifier
Therefore, it is not recommended to specify a specific column in the storage parameter of the default keyword of dbtune. You can create separate dbtune keywords to set these parameters. For information about dbtune keyword creation and parameter settings, see related topics of dbtune.