On Wed, Jan 30, 2019 at 2:11 PM Amit Kapila <amit.kapil...@gmail.com> wrote:
> This is much better than the earlier version of test and there is no
> dependency on the vacuum. However, I feel still there is some
> dependency on how the rows will fit in a page and we have seen some
> related failures due to alignment stuff. By looking at the test, I
> can't envision any such problem, but how about if we just write some
> simple tests where we can check that the FSM won't be created for very
> small number of records say one or two and then when we increase the
> records FSM gets created, here if we want, we can even use vacuum to
> ensure FSM gets created. Once we are sure that the main patch passes
> all the buildfarm tests, we can extend the test to something advanced
> as you are proposing now. I think that will reduce the chances of
> failure, what do you think?
That's probably a good idea to limit risk. I just very basic tests
now, and vacuum before every relation size check to make sure any FSM
extension (whether desired or not) is invoked. Also, in my last patch
I forgot to implement explicit checks of the block number instead of
assuming how many rows will fit on a page. I've used a plpgsql code
block to do this.
--
John Naylor https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
diff --git a/src/test/regress/expected/fsm.out b/src/test/regress/expected/fsm.out
index df6b15b9d2..eb2c3842e2 100644
--- a/src/test/regress/expected/fsm.out
+++ b/src/test/regress/expected/fsm.out
@@ -2,46 +2,30 @@
-- Free Space Map test
--
CREATE TABLE fsm_check_size (num int, str text);
--- Fill 3 blocks with as many large records as will fit
--- No FSM
-INSERT INTO fsm_check_size SELECT i, rpad('', 1024, 'a')
-FROM generate_series(1,7*3) i;
+-- With one block, there should be no FSM
+INSERT INTO fsm_check_size VALUES(1, 'a');
VACUUM fsm_check_size;
SELECT pg_relation_size('fsm_check_size', 'main') AS heap_size,
pg_relation_size('fsm_check_size', 'fsm') AS fsm_size;
heap_size | fsm_size
-----------+----------
- 24576 | 0
-(1 row)
-
--- Clear some space on block 0
-DELETE FROM fsm_check_size WHERE num <= 5;
-VACUUM fsm_check_size;
--- Insert small record in block 2 to set the cached smgr targetBlock
-INSERT INTO fsm_check_size VALUES(99, 'b');
--- Insert large record and make sure it goes in block 0 rather than
--- causing the relation to extend
-INSERT INTO fsm_check_size VALUES (101, rpad('', 1024, 'a'));
-SELECT pg_relation_size('fsm_check_size', 'main') AS heap_size,
-pg_relation_size('fsm_check_size', 'fsm') AS fsm_size;
- heap_size | fsm_size
------------+----------
- 24576 | 0
+ 8192 | 0
(1 row)
-- Extend table with enough blocks to exceed the FSM threshold
-- FSM is created and extended to 3 blocks
-INSERT INTO fsm_check_size SELECT i, 'c' FROM generate_series(200,1200) i;
-VACUUM fsm_check_size;
-SELECT pg_relation_size('fsm_check_size', 'fsm') AS fsm_size;
- fsm_size
-----------
- 24576
-(1 row)
-
--- Truncate heap to 1 block
--- No change in FSM
-DELETE FROM fsm_check_size WHERE num > 7;
+DO $$
+DECLARE curtid tid;
+num int;
+BEGIN
+num = 11;
+ LOOP
+ INSERT INTO fsm_check_size VALUES (num, 'b') RETURNING ctid INTO curtid;
+ EXIT WHEN curtid >= tid '(4, 0)';
+ num = num + 1;
+ END LOOP;
+END;
+$$;
VACUUM fsm_check_size;
SELECT pg_relation_size('fsm_check_size', 'fsm') AS fsm_size;
fsm_size
@@ -49,16 +33,6 @@ SELECT pg_relation_size('fsm_check_size', 'fsm') AS fsm_size;
24576
(1 row)
--- Truncate heap to 0 blocks
--- FSM now truncated to 2 blocks
-DELETE FROM fsm_check_size;
-VACUUM fsm_check_size;
-SELECT pg_relation_size('fsm_check_size', 'fsm') AS fsm_size;
- fsm_size
-----------
- 16384
-(1 row)
-
-- Add long random string to extend TOAST table to 1 block
INSERT INTO fsm_check_size
VALUES(0, (SELECT string_agg(md5(chr(i)), '')
diff --git a/src/test/regress/sql/fsm.sql b/src/test/regress/sql/fsm.sql
index 07f505591a..b1debedea1 100644
--- a/src/test/regress/sql/fsm.sql
+++ b/src/test/regress/sql/fsm.sql
@@ -4,42 +4,28 @@
CREATE TABLE fsm_check_size (num int, str text);
--- Fill 3 blocks with as many large records as will fit
--- No FSM
-INSERT INTO fsm_check_size SELECT i, rpad('', 1024, 'a')
-FROM generate_series(1,7*3) i;
-VACUUM fsm_check_size;
-SELECT pg_relation_size('fsm_check_size', 'main') AS heap_size,
-pg_relation_size('fsm_check_size', 'fsm') AS fsm_size;
+-- With one block, there should be no FSM
+INSERT INTO fsm_check_size VALUES(1, 'a');
--- Clear some space on block 0
-DELETE FROM fsm_check_size WHERE num <= 5;
VACUUM fsm_check_size;
-
--- Insert small record in block 2 to set the cached smgr targetBlock
-INSERT INTO fsm_check_size VALUES(99, 'b');
-
--- Insert large record and make sure it goes in block 0 rather than
--- causing the relation to extend
-INSERT INTO fsm_check_size VALUES (101, rpad('', 1024, 'a'));
SELECT pg_relation_size('fsm_check_size', 'main') AS heap_size,
pg_relation_size('fsm_check_size', 'fsm') AS fsm_size;
-- Extend table with enough blocks to exceed the FSM threshold
-- FSM is created and extended to 3 blocks
-INSERT INTO fsm_check_size SELECT i, 'c' FROM generate_series(200,1200) i;
-VACUUM fsm_check_size;
-SELECT pg_relation_size('fsm_check_size', 'fsm') AS fsm_size;
+DO $$
+DECLARE curtid tid;
+num int;
+BEGIN
+num = 11;
+ LOOP
+ INSERT INTO fsm_check_size VALUES (num, 'b') RETURNING ctid INTO curtid;
+ EXIT WHEN curtid >= tid '(4, 0)';
+ num = num + 1;
+ END LOOP;
+END;
+$$;
--- Truncate heap to 1 block
--- No change in FSM
-DELETE FROM fsm_check_size WHERE num > 7;
-VACUUM fsm_check_size;
-SELECT pg_relation_size('fsm_check_size', 'fsm') AS fsm_size;
-
--- Truncate heap to 0 blocks
--- FSM now truncated to 2 blocks
-DELETE FROM fsm_check_size;
VACUUM fsm_check_size;
SELECT pg_relation_size('fsm_check_size', 'fsm') AS fsm_size;
@@ -47,6 +33,7 @@ SELECT pg_relation_size('fsm_check_size', 'fsm') AS fsm_size;
INSERT INTO fsm_check_size
VALUES(0, (SELECT string_agg(md5(chr(i)), '')
FROM generate_series(1,100) i));
+
VACUUM fsm_check_size;
SELECT pg_relation_size(reltoastrelid, 'main') AS toast_size,
pg_relation_size(reltoastrelid, 'fsm') AS toast_fsm_size
