Name
ST_MemSize — Returns the amount of memory space a geometry takes.
Synopsis
integer
ST_MemSize
(
geometry
geomA
)
;
Description
Returns the amount of memory space (in bytes) the geometry takes.
This complements the PostgreSQL built-in database object functions pg_column_size, pg_size_pretty, pg_relation_size, pg_total_relation_size.
![[Note]](./images/note.png)
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pg_relation_size which gives the byte size of a table may return byte size lower than ST_MemSize. This is because pg_relation_size does not add toasted table contribution and large geometries are stored in TOAST tables. pg_total_relation_size - includes, the table, the toasted tables, and the indexes. pg_column_size returns how much space a geometry would take in a column considering compression, so may be lower than ST_MemSize |
This function supports 3d and will not drop the z-index.
This method supports Circular Strings and Curves.
This function supports Polyhedral surfaces.
This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).
Changed: 2.2.0 name changed to ST_MemSize to follow naming convention.
Examples
--Return how much byte space Boston takes up in our Mass data set
SELECT pg_size_pretty(SUM(ST_MemSize(geom))) as totgeomsum,
pg_size_pretty(SUM(CASE WHEN town = 'BOSTON' THEN ST_MemSize(geom) ELSE 0 END)) As bossum,
CAST(SUM(CASE WHEN town = 'BOSTON' THEN ST_MemSize(geom) ELSE 0 END)*1.00 /
SUM(ST_MemSize(geom))*100 As numeric(10,2)) As perbos
FROM towns;
totgeomsum bossum perbos
---------- ------ ------
1522 kB 30 kB 1.99
SELECT ST_MemSize(ST_GeomFromText('CIRCULARSTRING(220268 150415,220227 150505,220227 150406)'));
---
73
--What percentage of our table is taken up by just the geometry
SELECT pg_total_relation_size('public.neighborhoods') As fulltable_size, sum(ST_MemSize(geom)) As geomsize,
sum(ST_MemSize(geom))*1.00/pg_total_relation_size('public.neighborhoods')*100 As pergeom
FROM neighborhoods;
fulltable_size geomsize pergeom
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262144 96238 36.71188354492187500000