pg_readonly

pig build pkg pg_readonly;		# build deb

pig repo add pgsql -u   # add both repo and update cache

pig install pg_readonly;		# install via package name, for the active PG version

pig install pg_readonly -v 18;   # install for PG 18
pig install pg_readonly -v 17;   # install for PG 17
pig install pg_readonly -v 16;   # install for PG 16
pig install pg_readonly -v 15;   # install for PG 15
pig install pg_readonly -v 14;   # install for PG 14

shared_preload_libraries = 'pg_readonly';

CREATE EXTENSION pg_readonly;

SELECT get_cluster_readonly();
-- Returns false (read-write) or true (read-only)

SELECT set_cluster_readonly();

SELECT * FROM t;              -- OK
UPDATE t SET x = 33;          -- ERROR: pg_readonly: invalid statement because cluster is read-only
CREATE TABLE tmp(c text);     -- ERROR: pg_readonly: invalid statement because cluster is read-only

SELECT unset_cluster_readonly();