SET columnar.compression TO 'none';
SELECT count(distinct storageid) AS columnar_table_count FROM columnar.stripe \gset
CREATE TABLE t(a int, b int) USING columnar;
CREATE VIEW t_stripes AS
SELECT * FROM columnar.stripe a, pg_class b
WHERE a.storageid = columnar_relation_storageid(b.oid) AND b.relname='t';
SELECT count(*) FROM t_stripes;
 count
---------------------------------------------------------------------
     0
(1 row)

INSERT INTO t SELECT i, i * i FROM generate_series(1, 10) i;
INSERT INTO t SELECT i, i * i FROM generate_series(11, 20) i;
INSERT INTO t SELECT i, i * i FROM generate_series(21, 30) i;
SELECT sum(a), sum(b) FROM t;
 sum | sum
---------------------------------------------------------------------
 465 | 9455
(1 row)

SELECT count(*) FROM t_stripes;
 count
---------------------------------------------------------------------
     3
(1 row)

-- vacuum full should merge stripes together
VACUUM FULL t;
SELECT sum(a), sum(b) FROM t;
 sum | sum
---------------------------------------------------------------------
 465 | 9455
(1 row)

SELECT count(*) FROM t_stripes;
 count
---------------------------------------------------------------------
     1
(1 row)

-- test the case when all data cannot fit into a single stripe
SELECT alter_columnar_table_set('t', stripe_row_count => 1000);
 alter_columnar_table_set
---------------------------------------------------------------------

(1 row)

INSERT INTO t SELECT i, 2 * i FROM generate_series(1,2500) i;
SELECT sum(a), sum(b) FROM t;
   sum   |   sum
---------------------------------------------------------------------
 3126715 | 6261955
(1 row)

SELECT count(*) FROM t_stripes;
 count
---------------------------------------------------------------------
     4
(1 row)

VACUUM FULL t;
SELECT sum(a), sum(b) FROM t;
   sum   |   sum
---------------------------------------------------------------------
 3126715 | 6261955
(1 row)

SELECT count(*) FROM t_stripes;
 count
---------------------------------------------------------------------
     3
(1 row)

-- VACUUM FULL doesn't reclaim dropped columns, but converts them to NULLs
ALTER TABLE t DROP COLUMN a;
SELECT stripeid, attnum, chunkid, minimum_value IS NULL, maximum_value IS NULL
FROM columnar.chunk a, pg_class b
WHERE a.storageid = columnar_relation_storageid(b.oid) AND b.relname='t' ORDER BY 1, 2, 3;
 stripeid | attnum | chunkid | ?column? | ?column?
---------------------------------------------------------------------
        1 |      1 |       0 | f        | f
        1 |      2 |       0 | f        | f
        2 |      1 |       0 | f        | f
        2 |      2 |       0 | f        | f
        3 |      1 |       0 | f        | f
        3 |      2 |       0 | f        | f
(6 rows)

VACUUM FULL t;
SELECT stripeid, attnum, chunkid, minimum_value IS NULL, maximum_value IS NULL
FROM columnar.chunk a, pg_class b
WHERE a.storageid = columnar_relation_storageid(b.oid) AND b.relname='t' ORDER BY 1, 2, 3;
 stripeid | attnum | chunkid | ?column? | ?column?
---------------------------------------------------------------------
        1 |      1 |       0 | t        | t
        1 |      2 |       0 | f        | f
        2 |      1 |       0 | t        | t
        2 |      2 |       0 | f        | f
        3 |      1 |       0 | t        | t
        3 |      2 |       0 | f        | f
(6 rows)

-- Make sure we cleaned-up the transient table metadata after VACUUM FULL commands
SELECT count(distinct storageid) - :columnar_table_count FROM columnar.stripe;
 ?column?
---------------------------------------------------------------------
        1
(1 row)

-- do this in a transaction so concurrent autovacuum doesn't interfere with results
BEGIN;
SAVEPOINT s1;
SELECT count(*) FROM t;
 count
---------------------------------------------------------------------
  2530
(1 row)

SELECT pg_size_pretty(pg_relation_size('t'));
 pg_size_pretty
---------------------------------------------------------------------
 40 kB
(1 row)

INSERT INTO t SELECT i FROM generate_series(1, 10000) i;
SELECT pg_size_pretty(pg_relation_size('t'));
 pg_size_pretty
---------------------------------------------------------------------
 120 kB
(1 row)

SELECT count(*) FROM t;
 count
---------------------------------------------------------------------
 12530
(1 row)

ROLLBACK TO SAVEPOINT s1;
-- not truncated by VACUUM or autovacuum yet (being in transaction ensures this),
-- so relation size should be same as before.
SELECT pg_size_pretty(pg_relation_size('t'));
 pg_size_pretty
---------------------------------------------------------------------
 120 kB
(1 row)

COMMIT;
-- vacuum should truncate the relation to the usable space
VACUUM VERBOSE t;
INFO:  statistics for "t":
storage id: xxxxx
total file size: 122880, total data size: 10754
compression rate: 1.00x
total row count: 2530, stripe count: 3, average rows per stripe: 843
chunk count: 3, containing data for dropped columns: 0, none compressed: 3

INFO:  "t": truncated 15 to 5 pages
SELECT pg_size_pretty(pg_relation_size('t'));
 pg_size_pretty
---------------------------------------------------------------------
 40 kB
(1 row)

SELECT count(*) FROM t;
 count
---------------------------------------------------------------------
  2530
(1 row)

-- add some stripes with different compression types and create some gaps,
-- then vacuum to print stats
BEGIN;
SELECT alter_columnar_table_set('t',
    chunk_row_count => 1000,
    stripe_row_count => 2000,
    compression => 'pglz');
 alter_columnar_table_set
---------------------------------------------------------------------

(1 row)

SAVEPOINT s1;
INSERT INTO t SELECT i FROM generate_series(1, 1500) i;
ROLLBACK TO SAVEPOINT s1;
INSERT INTO t SELECT i / 5 FROM generate_series(1, 1500) i;
SELECT alter_columnar_table_set('t', compression => 'none');
 alter_columnar_table_set
---------------------------------------------------------------------

(1 row)

SAVEPOINT s2;
INSERT INTO t SELECT i FROM generate_series(1, 1500) i;
ROLLBACK TO SAVEPOINT s2;
INSERT INTO t SELECT i / 5 FROM generate_series(1, 1500) i;
COMMIT;
VACUUM VERBOSE t;
INFO:  statistics for "t":
storage id: xxxxx
total file size: 57344, total data size: 18808
compression rate: 1.25x
total row count: 5530, stripe count: 5, average rows per stripe: 1106
chunk count: 7, containing data for dropped columns: 0, none compressed: 5, pglz compressed: 2

SELECT count(*) FROM t;
 count
---------------------------------------------------------------------
  5530
(1 row)

-- check that we report chunks with data for dropped columns
ALTER TABLE t ADD COLUMN c int;
INSERT INTO t SELECT 1, i / 5 FROM generate_series(1, 1500) i;
ALTER TABLE t DROP COLUMN c;
VACUUM VERBOSE t;
INFO:  statistics for "t":
storage id: xxxxx
total file size: 73728, total data size: 31372
compression rate: 1.15x
total row count: 7030, stripe count: 6, average rows per stripe: 1171
chunk count: 11, containing data for dropped columns: 2, none compressed: 9, pglz compressed: 2

-- vacuum full should remove chunks for dropped columns
-- note that, a chunk will be stored in non-compressed for if compression
-- doesn't reduce its size.
SELECT alter_columnar_table_set('t', compression => 'pglz');
 alter_columnar_table_set
---------------------------------------------------------------------

(1 row)

VACUUM FULL t;
VACUUM VERBOSE t;
INFO:  statistics for "t":
storage id: xxxxx
total file size: 57344, total data size: 15728
compression rate: 1.96x
total row count: 7030, stripe count: 4, average rows per stripe: 1757
chunk count: 8, containing data for dropped columns: 0, none compressed: 2, pglz compressed: 6

DROP TABLE t;
DROP VIEW t_stripes;
-- Make sure we cleaned the metadata for t too
SELECT count(distinct storageid) - :columnar_table_count FROM columnar.stripe;
 ?column?
---------------------------------------------------------------------
        0
(1 row)

-- A table with high compression ratio
SET columnar.compression TO 'pglz';
SET columnar.stripe_row_count TO 1000000;
SET columnar.chunk_row_count TO 100000;
CREATE TABLE t(a int, b char, c text) USING columnar;
INSERT INTO t SELECT 1, 'a', 'xyz' FROM generate_series(1, 1000000) i;
VACUUM VERBOSE t;
INFO:  statistics for "t":
storage id: xxxxx
total file size: 630784, total data size: 604480
compression rate: 33.71x
total row count: 1000000, stripe count: 1, average rows per stripe: 1000000
chunk count: 30, containing data for dropped columns: 0, pglz compressed: 30

DROP TABLE t;