In this post, I am sharing few important function for finding the size of database, table and index in PostgreSQL.

Script 1 : Find a total size of the database.

SELECT pg_size_pretty(pg_database_size('db_employee'));

Script 2: Find a total size of the table with an index.

SELECT pg_size_pretty(pg_total_relation_size('Employee_Table'));

Script 3: Find a total size of the table without an index.

SELECT pg_size_pretty(pg_relation_size('Employee_table'));

Script 4: Find a total size of the index.

SELECT pg_size_pretty(pg_indexes_size('index_empid'));

Script 5: Find a total number of rows in a table.

SELECT COUNT(1) FROM Employee_table;

Script 6 : Find all the table size in the current database.

SELECT
    table_schema || '.' || table_name AS TableName,
    pg_size_pretty(pg_total_relation_size('"' || table_schema || '"."' || table_name || '"')) AS TableSize
FROM information_schema.tables
ORDER BY
    pg_total_relation_size('"' || table_schema || '"."' || table_name || '"') DESC

Script 7 : Find all the table and index size in the current database.

SELECT
    TableName
    ,pg_size_pretty(pg_table_size(TableName)) AS TableSize
    ,pg_size_pretty(pg_indexes_size(TableName)) AS IndexSize
    ,pg_size_pretty(pg_total_relation_size(TableName)) AS TotalSize
FROM 
(
     SELECT ('"' || table_schema || '"."' || table_name || '"') AS TableName
     FROM information_schema.tables
) AS Tables
ORDER BY 4 DESC