Use ST_SetTypeStorage to set the storage mode for specific data types-PolarDB(PolarDB)-阿里云帮助中心

Sets the storage mode for geometry or geography data types, controlling how many bytes are stored in-row versus off-row.

Syntax

bool ST_SetTypeStorage(cstring typeName, cstring storageStrategy, integer size);

Parameters

Parameter	Description
`typeName`	The data type to configure. Valid values: `geometry`, `geography`.
`storageStrategy`	The storage strategy. Set to `main`.
`size`	The number of bytes to store in-row.

Description

For spatial objects with large per-row sizes, storing metadata in-row and entity data off-row reduces disk I/O. During typical query and analysis workloads, PolarDB reads only the in-row metadata.

The size parameter controls how many bytes remain in-row. Setting size to 0 still uses main mode.

Use the following recommended values as a starting point:

Data type	Dimension	Recommended value (bytes)
`geometry`	2d (x,y)	24
	3d (x,y,z) and 3dm (x,y,m)	32
	4d (x,y,z,m)	40
`geography`	2d (x,y)	32

Example

Set the in-row storage size for geometry to 41 bytes:

SELECT ST_SetTypeStorage('geometry', 'main', 41);
 st_settypestorage
-------------------
 t
(1 row)

The function returns t (true) on success.