rlliso3multi.sql

来自「derby database source code.good for you.」· SQL 代码 · 共 496 行 · 第 1/2 页

connect 'wombat' as inserter;
set isolation to rr;
-- by default, holdability of ResultSet objects created using this Connection object is true. Following will set it to false for this connection.
NoHoldForConnection;


set connection scanner;
autocommit off;
create table test_5 (a int, b varchar(1000), c varchar(1000));
insert into test_5 values (1, PADSTRING('a',1000), PADSTRING('a',1000));
insert into test_5 values (2, PADSTRING('b',1000), PADSTRING('b',1000));
create index test_5_idx on test_5 (a);
commit;

set connection inserter;
autocommit off;
commit;


--------------------------------------------------------------------------------
-- Set up scanner to be doing a row locked index to base row scan on the index.
-- By using group fetch it will read and release locks on multiple rows from
-- the index and save away row pointers from the index.
--------------------------------------------------------------------------------
set connection scanner;
CALL SYSCS_UTIL.SYSCS_SET_DATABASE_PROPERTY('derby.language.bulkFetchDefault','10');
get cursor scan_cursor as 
    'select a, b from test_5 where a <= 2 ';
call SYSCS_UTIL.SYSCS_SET_DATABASE_PROPERTY('derby.language.bulkFetchDefault', '16');

-- because of group locking will get locks on 1, 2, 3, 4, and 5 and then will
-- release the locks on 1, 2, 3, and 4.  The last one is released on close or
-- on next call emptying the cursor.
next scan_cursor;

--------------------------------------------------------------------------------
-- Insert a row previous to all other rows, this should block and back out.
--------------------------------------------------------------------------------
set connection inserter;
insert into test_5 values (0, PADSTRING('b',1000), PADSTRING('b',1000));

--------------------------------------------------------------------------------
-- The scan should finish fine without blocking.
--------------------------------------------------------------------------------
set connection scanner;
next scan_cursor;
next scan_cursor;

-- commit the insert
set connection inserter;
commit;

-- scanner should now see 1 and 2
set connection scanner;
close scan_cursor;

select a from test_5;

--------------------------------------------------------------------------------
-- cleanup.
--------------------------------------------------------------------------------
set connection inserter;
commit;
disconnect;
set connection scanner;
commit;
drop table test_5;
commit;
disconnect;


--------------------------------------------------------------------------------
-- Test 6: test update locks
--------------------------------------------------------------------------------

connect 'wombat' as t6scanner;
set isolation to rr;
-- by default, holdability of ResultSet objects created using this Connection object is true. Following will set it to false for this connection.
NoHoldForConnection;

connect 'wombat' as t6updater;
set isolation to rr;
-- by default, holdability of ResultSet objects created using this Connection object is true. Following will set it to false for this connection.
NoHoldForConnection;

connect 'wombat' as t6writer;
set isolation to rr;
-- by default, holdability of ResultSet objects created using this Connection object is true. Following will set it to false for this connection.
NoHoldForConnection;

run resource 'LockTableQuery.subsql';

-- set up
set connection t6updater;
autocommit off;
create table test_6 (a int, b int);
insert into test_6 values (1,1);
insert into test_6 values (2,2);
insert into test_6 values (8,8);
create index test6_idx on test_6 (a);
commit;

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

--
--==================================================
-- t6updater gets an update lock on row where a=1
--==================================================

get cursor update_cursor as
    'select b from test_6 where a=1 for update of b';

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

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

set connection t6scanner;
autocommit off;

--
--------------------------------------------------
-- try to scan the table, should timeout
--------------------------------------------------
select * from test_6;
select * from lock_table order by tabname, type desc, mode, cnt, lockname;

--
--------------------------------------------------
-- try to update the table, should timeout
--------------------------------------------------
update test_6 set b=99 where a = 1;

--
--------------------------------------------------
-- try to update the table, should timeout (previous key is locked)
--------------------------------------------------
update test_6 set b=99 where a = 2;

--
--------------------------------------------------
-- try to update the table, should go through
--------------------------------------------------
update test_6 set b=99 where a = 8;
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;

--
--------------------------------------------------
-- try to get an update lock
--------------------------------------------------
get cursor update_cursor2 as
    'select b from test_6 where a=1 for update of b';
select * from lock_table order by tabname, type desc, mode, cnt, lockname;

--
--------------------------------------------------
-- should timeout (other transaction has a shared lock on this row)
--------------------------------------------------
next update_cursor2;
select * from lock_table order by tabname, type desc, mode, cnt, lockname;

--
--------------------------------------------------
-- should succeed (no other transaction has a shared lock on this row)
--------------------------------------------------
get cursor update_cursor3 as
    'select b from test_6 where a=8 for update of b';
select type, cnt, mode, tabname, lockname, state from lock_table2 order by tabname, type desc, mode, cnt, lockname;

next update_cursor3;
select * from lock_table order by tabname, type desc, mode, cnt, lockname;

commit;
close update_cursor2;
close update_cursor3;

set connection t6updater;
commit;
close update_cursor;

set connection t6scanner;
select * from lock_table order by tabname, type desc, mode, cnt, lockname;

--
--==================================================
-- t6scanner gets a read lock
--==================================================

select b from test_6 where a=1;
select * from lock_table order by tabname, type desc, mode, cnt, lockname;


--
--------------------------------------------------
-- should succeed (can get an update lock if there is already a shared lock)
--------------------------------------------------
set connection t6updater;
get cursor update_cursor as
    'select b from test_6 where a=1 for update of b';
next update_cursor;
select * from lock_table order by tabname, type desc, mode, cnt, lockname;

commit;
close update_cursor;

set connection t6scanner;
commit;

--
--==================================================
-- t6writer gets a write lock
--==================================================

set connection t6writer;
autocommit off;
update test_6 set b=77 where a=2;
select * from lock_table order by tabname, type desc, mode, cnt, lockname;

set connection t6updater;
get cursor update_cursor as
    'select b from test_6 where a=2 for update of b';
select * from lock_table order by tabname, type desc, mode, cnt, lockname;
--
----------------------------------------------------
-- should timeout
----------------------------------------------------
next update_cursor;


--------------------------------------------------------------------------------
-- cleanup.
--------------------------------------------------------------------------------
set connection t6updater;
close update_cursor;
drop table test_6;
commit;
disconnect;
set connection t6scanner;
disconnect;
set connection t6writer;
disconnect;

exit;