readbtreesetlocks.subsql

derby database source code.good for you.

-- Basic single user testing of read locks on select "set" queries on indexes.
--
-- This ".subsql" test is
-- meant to be run from another test such that it gets run under multiple
-- isolation levels.  This is important as they behave
-- differently, depending on isolation levels.
--
-- assume's caller has already done: run 'LockTableQuery.subsql'; to get 
-- easy access to the lock VTI.

-- TEST 0: btree scan
-- TEST 1: btree scan, (scan table with some deleted rows)
-- TEST 2: btree scan, (scan with "<" qualifier)
-- TEST 3: btree scan, (scan with equals qualifier)
-- TEST 4: btree scan, (equals qualifier, no rows return)

autocommit off;

--------------------------------------------------------------------------------
-- Assumes that calling routine has set up the following simple dataset, 
-- a heap, and index with following initial values:
--     create table a (a int, b int, c somesortofchar, [index_pad]);
--     create index a_idx on a (a) or a_idx on a (a, index_pad);
--
-- 1, 10, 'one'
-- 2, 20, 'two'
-- 3, 30, 'three'
-- 4, 40, 'four'
-- 5, 50, 'five'
-- 6, 60, 'six'
-- 7, 70, 'seven'
--------------------------------------------------------------------------------
select * from a;
commit;

--------------------------------------------------------------------------------
-- TEST 0: btree scan
-- Test full scan.
--    ALL MODES        - TABLE IS, "scan page lockname of form (pageno, 1) 
--    SERIALIZABLE     - row S locks as it visits each row, row/table lock 
--                       held until end xact.  Also holds one previous key lock.
--    REPEATABLE READ  - row S locks as it visits each row, row/table locks held
--                       until end of transaction.
--    READ COMMITTED   - instantaneous S locks requested on each row.  No locks
--                       held after query finishes.
--    READ UNCOMMITTED - no row locks.  No locks held after query finishes.
--------------------------------------------------------------------------------
select a from a;
select * from lock_table order by tabname, type desc, mode, cnt, lockname;
commit;

select * from lock_table order by tabname, type desc, mode, cnt, lockname;
commit;


--------------------------------------------------------------------------------
-- TEST 1: btree scan, (scan table with some deleted rows)
-- Test full scan on a data set with some deleted rows (the "even" ones).
--    ALL MODES        - TABLE IS, "scan page lockname of form (pageno, 1) 
--    SERIALIZABLE     - row S locks as it visits each row, row/table lock 
--                       held until end xact.  Also holds one previous key lock.
--    REPEATABLE READ  - row S locks as it visits each row, row/table locks held
--                       until end of transaction.
--    READ COMMITTED   - instantaneous S locks requested on each row.  No locks
--                       held after query finishes.
--    READ UNCOMMITTED - no row locks.  No locks held after query finishes.
--
-- After the delete the base table should look like:
-- 1, 10, 'one'
-- 3, 30, 'three'
-- 5, 50, 'five'
-- 7, 70, 'seven'
--------------------------------------------------------------------------------
delete from a where a = 2 or a = 4 or a = 6;
commit;

select a from a;
select * from lock_table order by tabname, type desc, mode, cnt, lockname;
commit;

select * from lock_table order by tabname, type desc, mode, cnt, lockname;
commit;


--------------------------------------------------------------------------------
-- TEST 2: btree scan, (scan with "<" qualifier)
-- Test "less than" qualified scan on a data set.
--    ALL MODES        - TABLE IS, "scan page lockname of form (pageno, 1) 
--    SERIALIZABLE     - row S locks as it visits each row, row/table lock 
--                       held until end xact.  Also holds one previous key lock.
--    REPEATABLE READ  - row S locks as it visits each row, row/table locks held
--                       until end of transaction.
--    READ COMMITTED   - instantaneous S locks requested on each row.  No locks
--                       held after query finishes.
--    READ UNCOMMITTED - no row locks.  No locks held after query finishes.
--
-- At this point the base table should look like:
-- 1, 10, 'one'
-- 3, 30, 'three'
-- 5, 50, 'five'
-- 7, 70, 'seven'
--------------------------------------------------------------------------------

select a from a where a < 3;
select * from lock_table order by tabname, type desc, mode, cnt, lockname;
commit;

select * from lock_table order by tabname, type desc, mode, cnt, lockname;
commit;

--------------------------------------------------------------------------------
-- TEST 3: btree scan, (scan with equals qualifier)
-- Test "equals" qualified cursor scan on a data set.
--    ALL MODES        - TABLE IS, "scan page lockname of form (pageno, 1) 
--    SERIALIZABLE     - row S locks as it visits each row, row/table lock 
--                       held until end xact.  Also holds one previous key lock.
--    REPEATABLE READ  - row S locks as it visits each row, row/table locks held
--                       until end of transaction.
--    READ COMMITTED   - instantaneous S locks requested on each row.  No locks
--                       held after query finishes.
--    READ UNCOMMITTED - no row locks.  No locks held after query finishes.
--
-- At this point the base table should look like:
-- 1, 10, 'one'
-- 3, 30, 'three'
-- 5, 50, 'five'
-- 7, 70, 'seven'
--------------------------------------------------------------------------------

select a from a where a = 5;
select * from lock_table order by tabname, type desc, mode, cnt, lockname;
commit;

select * from lock_table order by tabname, type desc, mode, cnt, lockname;
commit;

--------------------------------------------------------------------------------
-- TEST  4: btree scan, (equals qualifier, no rows return)
-- Test "equals" qualified scan on a data set, no rows returned.
--    ALL MODES        - TABLE IS, "scan page lockname of form (pageno, 1) 
--    SERIALIZABLE     - row S locks as it visits each row, row/table lock 
--                       held until end xact.  Also holds one previous key lock.
--    REPEATABLE READ  - row S locks as it visits each row, row/table locks held
--                       until end of transaction.
--    READ COMMITTED   - instantaneous S locks requested on each row.  No locks
--                       held after query finishes.
--    READ UNCOMMITTED - no row locks.  No locks held after query finishes.
--
-- At this point the base table should look like:
-- 1, 10, 'one'
-- 3, 30, 'three'
-- 5, 50, 'five'
-- 7, 70, 'seven'
--------------------------------------------------------------------------------

-- no rows expected to qualify
select a from a where a = 42;
select * from lock_table order by tabname, type desc, mode, cnt, lockname;
commit;

select * from lock_table order by tabname, type desc, mode, cnt, lockname;
commit;

drop table a;