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create extension pg_surgery;
-- create a normal heap table and insert some rows.
-- use a temp table so that vacuum behavior doesn't depend on global xmin
create temp table htab (a int);
insert into htab values (100), (200), (300), (400), (500);
-- test empty TID array
select heap_force_freeze('htab'::regclass, ARRAY[]::tid[]);
heap_force_freeze
-------------------
(1 row)
-- nothing should be frozen yet
select * from htab where xmin = 2;
a
---
(0 rows)
-- freeze forcibly
select heap_force_freeze('htab'::regclass, ARRAY['(0, 4)']::tid[]);
heap_force_freeze
-------------------
(1 row)
-- now we should have one frozen tuple
select ctid, xmax from htab where xmin = 2;
ctid | xmax
-------+------
(0,4) | 0
(1 row)
-- kill forcibly
select heap_force_kill('htab'::regclass, ARRAY['(0, 4)']::tid[]);
heap_force_kill
-----------------
(1 row)
-- should be gone now
select * from htab where ctid = '(0, 4)';
a
---
(0 rows)
-- should now be skipped because it's already dead
select heap_force_kill('htab'::regclass, ARRAY['(0, 4)']::tid[]);
NOTICE: skipping tid (0, 4) for relation "htab" because it is marked dead
heap_force_kill
-----------------
(1 row)
select heap_force_freeze('htab'::regclass, ARRAY['(0, 4)']::tid[]);
NOTICE: skipping tid (0, 4) for relation "htab" because it is marked dead
heap_force_freeze
-------------------
(1 row)
-- freeze two TIDs at once while skipping an out-of-range block number
select heap_force_freeze('htab'::regclass,
ARRAY['(0, 1)', '(0, 3)', '(1, 1)']::tid[]);
NOTICE: skipping block 1 for relation "htab" because the block number is out of range
heap_force_freeze
-------------------
(1 row)
-- we should now have two frozen tuples
select ctid, xmax from htab where xmin = 2;
ctid | xmax
-------+------
(0,1) | 0
(0,3) | 0
(2 rows)
-- out-of-range TIDs should be skipped
select heap_force_freeze('htab'::regclass, ARRAY['(0, 0)', '(0, 6)']::tid[]);
NOTICE: skipping tid (0, 0) for relation "htab" because the item number is out of range
NOTICE: skipping tid (0, 6) for relation "htab" because the item number is out of range
heap_force_freeze
-------------------
(1 row)
-- set up a new table with a redirected line pointer
-- use a temp table so that vacuum behavior doesn't depend on global xmin
create temp table htab2(a int);
insert into htab2 values (100);
update htab2 set a = 200;
vacuum htab2;
-- redirected TIDs should be skipped
select heap_force_kill('htab2'::regclass, ARRAY['(0, 1)']::tid[]);
NOTICE: skipping tid (0, 1) for relation "htab2" because it redirects to item 2
heap_force_kill
-----------------
(1 row)
-- now create an unused line pointer
select ctid from htab2;
ctid
-------
(0,2)
(1 row)
update htab2 set a = 300;
select ctid from htab2;
ctid
-------
(0,3)
(1 row)
vacuum freeze htab2;
-- unused TIDs should be skipped
select heap_force_kill('htab2'::regclass, ARRAY['(0, 2)']::tid[]);
NOTICE: skipping tid (0, 2) for relation "htab2" because it is marked unused
heap_force_kill
-----------------
(1 row)
-- multidimensional TID array should be rejected
select heap_force_kill('htab2'::regclass, ARRAY[['(0, 2)']]::tid[]);
ERROR: argument must be empty or one-dimensional array
-- TID array with nulls should be rejected
select heap_force_kill('htab2'::regclass, ARRAY[NULL]::tid[]);
ERROR: array must not contain nulls
-- but we should be able to kill the one tuple we have
select heap_force_kill('htab2'::regclass, ARRAY['(0, 3)']::tid[]);
heap_force_kill
-----------------
(1 row)
-- materialized view.
-- note that we don't commit the transaction, so autovacuum can't interfere.
begin;
create materialized view mvw as select a from generate_series(1, 3) a;
select * from mvw where xmin = 2;
a
---
(0 rows)
select heap_force_freeze('mvw'::regclass, ARRAY['(0, 3)']::tid[]);
heap_force_freeze
-------------------
(1 row)
select * from mvw where xmin = 2;
a
---
3
(1 row)
select heap_force_kill('mvw'::regclass, ARRAY['(0, 3)']::tid[]);
heap_force_kill
-----------------
(1 row)
select * from mvw where ctid = '(0, 3)';
a
---
(0 rows)
rollback;
-- check that it fails on an unsupported relkind
create view vw as select 1;
select heap_force_kill('vw'::regclass, ARRAY['(0, 1)']::tid[]);
ERROR: cannot operate on relation "vw"
DETAIL: This operation is not supported for views.
select heap_force_freeze('vw'::regclass, ARRAY['(0, 1)']::tid[]);
ERROR: cannot operate on relation "vw"
DETAIL: This operation is not supported for views.
-- cleanup.
drop view vw;
drop extension pg_surgery;
|
