How to check table UNLOGGED with postgresql?

Question

CREATE UNLOGGED TABLE IF NOT EXISTS <tablename>

How can I first check if the desired table is created UNLOGGED, and if not alter the table accordingly?

postgres 9.4

Answer 1

You can check column relpersistence of table pg_class;

postgres=# select relpersistence, relname from pg_class where relname like 'foo%';
┌────────────────┬─────────┐
│ relpersistence │ relname │
╞════════════════╪═════════╡
│ p              │ foo     │
│ p              │ foo1    │
│ u              │ foo2    │
└────────────────┴─────────┘
(3 rows)

foo2 is unlogged table.