SHOW server_version \gset
SELECT substring(:'server_version', '\d+')::int >= 15 AS server_version_ge_15
\gset
\if :server_version_ge_15
\else
\q
\endif
CREATE TABLE alter_am(i int);
CREATE TABLE
INSERT INTO alter_am SELECT generate_series(1,1000000);
INSERT 0 1000000
SELECT * FROM columnar.options WHERE regclass = 'alter_am'::regclass;
 regclass | chunk_group_row_limit | stripe_row_limit | compression_level | compression
---------------------------------------------------------------------
(0 rows)

SELECT SUM(i) FROM alter_am;
     sum
---------------------------------------------------------------------
 500000500000
(1 row)

ALTER TABLE alter_am
  SET ACCESS METHOD columnar,
  SET (columnar.compression = pglz, fillfactor = 20);
ALTER TABLE
SELECT * FROM columnar.options WHERE regclass = 'alter_am'::regclass;
 regclass | chunk_group_row_limit | stripe_row_limit | compression_level | compression
---------------------------------------------------------------------
 alter_am |                 10000 |           150000 |                 3 | pglz
(1 row)

SELECT SUM(i) FROM alter_am;
     sum
---------------------------------------------------------------------
 500000500000
(1 row)

ALTER TABLE alter_am SET ACCESS METHOD heap;
ALTER TABLE
-- columnar options should be gone
SELECT * FROM columnar.options WHERE regclass = 'alter_am'::regclass;
 regclass | chunk_group_row_limit | stripe_row_limit | compression_level | compression
---------------------------------------------------------------------
(0 rows)

SELECT SUM(i) FROM alter_am;
     sum
---------------------------------------------------------------------
 500000500000
(1 row)

-- error: setting columnar options must happen after converting to columnar
ALTER TABLE alter_am
  SET (columnar.stripe_row_limit = 1111),
  SET ACCESS METHOD columnar;
ERROR:  ALTER TABLE cannot alter the access method after altering storage parameters
HINT:  Specify SET ACCESS METHOD before storage parameters, or use separate ALTER TABLE commands.
DROP TABLE alter_am;
DROP TABLE