jsonb storage size bench

jsonb_key_size_bench.sql

-- Check "JSONB storage does not deduplicate the key names in the JSON. This can result in considerably larger storage footprint.. " from https://scalegrid.io/blog/using-jsonb-in-postgresql-how-to-effectively-store-index-json-data-in-postgresql/
create table jt_1 (a integer, b numeric, c text);
create table jt_2 (data jsonb);
create table jt_3 (data jsonb);
create table jt_4 (data jsonb);


-- 10 million records for jt_1 and jt_2
insert into jt_1 SELECT (random() * 100000)::integer,
                        (random() * 1000000)::numeric,
                        md5(random()::text) FROM generate_series(1, 10000000);

insert into jt_2 SELECT jsonb_build_object('aaa', (random() * 100000)::integer,
                                           'bbb', (random() * 1000000),
                                           'ccc', md5(random()::text)) FROM generate_series(1, 10000000);


-- 1 million records for jt_3 and jt_4
insert into jt_3 SELECT jsonb_build_object('aaa', (random() * 100000)::integer,
                                           'bbb', (random() * 1000000),
                                           'ccc', md5(random()::text))  FROM generate_series(1, 1000000);

-- longer keys in jt_4
insert into jt_4 SELECT jsonb_build_object('aaa123444378590', (random() * 100000)::integer,
                          'bbbSomeMuchMuchLongerKey', (random() * 1000000),
                          repeat('abcde', 10), md5(random()::text))  FROM generate_series(1, 1000000);

-- res * 
 table_name | row_estimate  |   toast    |  table  
------------+---------------+------------+---------
 jt_1       |   9.99465e+06 | 8192 bytes | 879 MB
 jt_2       | 1.0000059e+07 | 8192 bytes | 1281 MB
 jt_3       |         1e+06 | 8192 bytes | 128 MB
 jt_4       |         1e+06 | 8192 bytes | 206 MB
(4 rows)

-- *
SELECT  table_name
        , row_estimate
          , pg_size_pretty(toast_bytes) as toast
       , pg_size_pretty(table_bytes) AS table
  FROM (
    SELECT *, total_bytes-index_bytes-coalesce(toast_bytes,0) AS table_bytes FROM (
      SELECT c.oid,nspname AS table_schema, relname AS table_name
             , c.reltuples AS row_estimate
             , pg_total_relation_size(c.oid) AS total_bytes
             , pg_indexes_size(c.oid) AS index_bytes
             , pg_total_relation_size(reltoastrelid) AS toast_bytes
        FROM pg_class c
               LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
       WHERE relkind = 'r'
    ) a
  ) a where table_name LIKE 'jt_%';