Queries the MD5 hash string of a raster object.

Syntax

text ST_MD5Sum(raster raster_obj)

Parameters

Parameter Description
raster_obj The name of the raster object.

Description

The system searches the metadata of the raster object to obtain the MD5 hash string. If the MD5 hash string cannot be found, the system returns a NULL value. Then, the system calculates the MD5 hash string based on the Alibaba Cloud Object Storage Service (OSS) path where the raster object is stored.

The following table describes the parameters that you need to configure.

Parameter Type Description
ganos.raster.calculate_md5 boolean Specifies whether to calculate the MD5 hash string and saves it to the metadata when the raster object is stored. Valid values: true | false. Default value: false. Example: 
Set ganos.raster.calculate_md5 = true;
ganos.raster.md5sum_chunk_size integer Specifies the size of data that can be cached for each read operation when the system calculates the MD5 hash string. Unit: MB. Valid values: 1 to 256. Default value: 10. Example: 
Set ganos.raster.md5sum_chunk_size = 20;

Examples

SELECT ST_MD5SUM(rast)
FROM raster_table
WHERE id = 1;

              st_md5sum
-----------------------------------
 21f41fd983d3139c75b04bff2b7bf5c9