pg_attribute_encoding
The pg_attribute_encoding system catalog table in the pg_catalog schema contains column storage information.
| column | type | modifers | storage | description | 
|---|---|---|---|---|
| attrelid | oid | not null | plain | Foreign key to pg_attribute.attrelid | 
| attnum | smallint | not null | plain | Foreign key to pg_attribute.attnum | 
| filenum | smallint | not null | plain | The column file number | 
| attoptions | text [ ] | extended | The options | 
For a column with filenum = f, the column files on disk use the suffix (f - 1)*128 to f*128 - 1. For example:
- Column with filenum = 1has filesrelfilenode,relfilenode.1..relfilenode.127.
- Column with filenum = 2has filesrelfilenode.128,relfilenode.129..relfilenode.255.
- Column with filenum = 3has filesrelfilenode.256,relfilenode.257..relfilenode.383.