Strange size of the table

Baumi · #1 (**permalink**) 07-02-12, 10:05

Hi,

I have a table with columns and constraints:

Code:

  height smallint,
  length smallint,
  diameter smallint,
  volume integer,
  idsensorfragments integer,
  CONSTRAINT sensorstats_idsensorfragments_fkey FOREIGN KEY (idsensorfragments)
      REFERENCES sensorfragments (idsensorfragments) MATCH SIMPLE
      ON UPDATE CASCADE ON DELETE CASCADE

(no primary key). There is currently 28 978 112 records in it, but the size of the table is way too much in my opinion.

Result of the query:

Code:

select pg_size_pretty(pg_total_relation_size('sensorstats')), pg_size_pretty(pg_relation_size('sensorstats'))

is:

Code:

"1849 MB";"1226 MB"

There is just one index on idsensorfragments column. Using simple math you can see that one record takes ~66,7 B (?!?!). Can anyone explain me where this number comes from?

5 columns = 2 + 2 + 2 + 4 + 4 = 14 Bytes. I have one index, no primary key. Where additional 50B per record comes from?

Thanks!

P.S. Table was vacuumed, analyzed and reindexed.

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