Script to measure the size of Postgres Table row and Data page

postgres_table_size.sql

WITH cteTableInfo AS 
(
	SELECT 
		COUNT(1) AS ct
		,SUM(length(t::text)) AS TextLength  
		,'PUBLIC.MY_TABLE'::regclass AS TableName  
	FROM PUBLIC.MY_TABLE AS t  
)
,cteRowSize AS 
(
   SELECT ARRAY [pg_relation_size(TableName)
               , pg_relation_size(TableName, 'vm')
               , pg_relation_size(TableName, 'fsm')
               , pg_table_size(TableName)
               , pg_indexes_size(TableName)
               , pg_total_relation_size(TableName)
               , TextLength
             ] AS val
        , ARRAY ['Total Relation Size'
               , 'Visibility Map'
               , 'Free Space Map'
               , 'Table Included Toast Size'
               , 'Indexes Size'
               , 'Total Toast and Indexes Size'
               , 'Live Row Byte Size'
             ] AS Name
   FROM cteTableInfo
)
SELECT 
	unnest(name) AS Description
	,unnest(val) AS Bytes
	,pg_size_pretty(unnest(val)) AS BytesPretty
	,unnest(val) / ct AS bytes_per_row
FROM cteTableInfo, cteRowSize
 
UNION ALL SELECT '------------------------------', NULL, NULL, NULL
UNION ALL SELECT 'TotalRows', ct, NULL, NULL FROM cteTableInfo
UNION ALL SELECT 'LiveTuples', pg_stat_get_live_tuples(TableName), NULL, NULL FROM cteTableInfo
UNION ALL SELECT 'DeadTuples', pg_stat_get_dead_tuples(TableName), NULL, NULL FROM cteTableInfo;