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Fixed BUG#15737: Stored procedure optimizer bug with LEAVE

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Second version.
  The problem was that the optimizer didn't work correctly with forwards jumps
  to "no-op" hpop and cpop instructions.
  Don't generate "no-op" instructions (hpop 0 and cpop 0), it isn't actually
  necessary.
This commit is contained in:
pem@mysql.com
2006-01-25 15:11:49 +01:00
parent 378147a23d
commit f60a763208
5 changed files with 321 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files

139
mysql-test/r/sp-code.result
View File

@ -1,3 +1,5 @@
drop procedure if exists empty;
drop procedure if exists code_sample;
create procedure empty()
begin
end;
@ -60,3 +62,140 @@ Pos Instruction
20 cpop 1
21 stmt 0 "select t.name, t.idx from t2 t order ..."
drop procedure code_sample;
drop procedure if exists sudoku_solve;
create procedure sudoku_solve(p_naive boolean, p_all boolean)
deterministic
modifies sql data
begin
drop temporary table if exists sudoku_work, sudoku_schedule;
create temporary table sudoku_work
(
row smallint not null,
col smallint not null,
dig smallint not null,
cnt smallint,
key using btree (cnt),
key using btree (row),
key using btree (col),
unique key using hash (row,col)
);
create temporary table sudoku_schedule
(
idx int not null auto_increment primary key,
row smallint not null,
col smallint not null
);
call sudoku_init();
if p_naive then
update sudoku_work set cnt = 0 where dig = 0;
else
call sudoku_count();
end if;
insert into sudoku_schedule (row,col)
select row,col from sudoku_work where cnt is not null order by cnt desc;
begin
declare v_scounter bigint default 0;
declare v_i smallint default 1;
declare v_dig smallint;
declare v_schedmax smallint;
select count(*) into v_schedmax from sudoku_schedule;
more:
loop
begin
declare v_tcounter bigint default 0;
sched:
while v_i <= v_schedmax do
begin
declare v_row, v_col smallint;
select row,col into v_row,v_col from sudoku_schedule where v_i = idx;
select dig into v_dig from sudoku_work
where v_row = row and v_col = col;
case v_dig
when 0 then
set v_dig = 1;
update sudoku_work set dig = 1
where v_row = row and v_col = col;
when 9 then
if v_i > 0 then
update sudoku_work set dig = 0
where v_row = row and v_col = col;
set v_i = v_i - 1;
iterate sched;
else
select v_scounter as 'Solutions';
leave more;
end if;
else
set v_dig = v_dig + 1;
update sudoku_work set dig = v_dig
where v_row = row and v_col = col;
end case;
set v_tcounter = v_tcounter + 1;
if not sudoku_digit_ok(v_row, v_col, v_dig) then
iterate sched;
end if;
set v_i = v_i + 1;
end;
end while sched;
select dig from sudoku_work;
select v_tcounter as 'Tests';
set v_scounter = v_scounter + 1;
if p_all and v_i > 0 then
set v_i = v_i - 1;
else
leave more;
end if;
end;
end loop more;
end;
drop temporary table sudoku_work, sudoku_schedule;
end//
show procedure code sudoku_solve;
Pos Instruction
0 stmt 9 "drop temporary table if exists sudoku..."
1 stmt 1 "create temporary table sudoku_work ( ..."
2 stmt 1 "create temporary table sudoku_schedul..."
3 stmt 95 "call sudoku_init("
4 jump_if_not 7(8) p_naive@0
5 stmt 4 "update sudoku_work set cnt = 0 where ..."
6 jump 8
7 stmt 95 "call sudoku_count("
8 stmt 6 "insert into sudoku_schedule (row,col)..."
9 set v_scounter@2 0
10 set v_i@3 1
11 set v_dig@4 NULL
12 set v_schedmax@5 NULL
13 stmt 0 "select count(*) into v_schedmax from ..."
14 set v_tcounter@6 0
15 jump_if_not 39(39) (v_i@3 <= v_schedmax@5)
16 set v_row@7 NULL
17 set v_col@8 NULL
18 stmt 0 "select row,col into v_row,v_col from ..."
19 stmt 0 "select dig into v_dig from sudoku_wor..."
20 set_case_expr 0 v_dig@4
21 jump_if_not 25(34) (case_expr@0 = 0)
22 set v_dig@4 1
23 stmt 4 "update sudoku_work set dig = 1 where ..."
24 jump 34
25 jump_if_not 32(34) (case_expr@0 = 9)
26 jump_if_not 30(34) (v_i@3 > 0)
27 stmt 4 "update sudoku_work set dig = 0 where ..."
28 set v_i@3 (v_i@3 - 1)
29 jump 15
30 stmt 0 "select v_scounter as 'Solutions'"
31 jump 45
32 set v_dig@4 (v_dig@4 + 1)
33 stmt 4 "update sudoku_work set dig = v_dig wh..."
34 set v_tcounter@6 (v_tcounter@6 + 1)
35 jump_if_not 37(37) not(`test`.`sudoku_digit_ok`(v_row@7,v_col@8,v_dig@4))
36 jump 15
37 set v_i@3 (v_i@3 + 1)
38 jump 15
39 stmt 0 "select dig from sudoku_work"
40 stmt 0 "select v_tcounter as 'Tests'"
41 set v_scounter@2 (v_scounter@2 + 1)
42 jump_if_not 45(14) (p_all@1 and (v_i@3 > 0))
43 set v_i@3 (v_i@3 - 1)
44 jump 14
45 stmt 9 "drop temporary table sudoku_work, sud..."
drop procedure sudoku_solve;

143
mysql-test/t/sp-code.test
View File

@ -4,6 +4,11 @@
-- source include/is_debug_build.inc
--disable_warnings
drop procedure if exists empty;
drop procedure if exists code_sample;
--enable_warnings
create procedure empty()
begin
end;
@ -47,3 +52,141 @@ end//
delimiter ;//
show procedure code code_sample;
drop procedure code_sample;
#
# BUG#15737: Stored procedure optimizer bug with LEAVE
#
# This is a much more extensive test case than is strictly needed,
# but it was kept as is for two reasons:
# - The bug occurs under some quite special circumstances, so it
# wasn't trivial to create a smaller test,
# - There's some value in having another more complex code sample
# in this test file. This might catch future code generation bugs
# that doesn't not show in behaviour in any obvious way.
--disable_warnings
drop procedure if exists sudoku_solve;
--enable_warnings
delimiter //;
create procedure sudoku_solve(p_naive boolean, p_all boolean)
deterministic
modifies sql data
begin
drop temporary table if exists sudoku_work, sudoku_schedule;
create temporary table sudoku_work
(
row smallint not null,
col smallint not null,
dig smallint not null,
cnt smallint,
key using btree (cnt),
key using btree (row),
key using btree (col),
unique key using hash (row,col)
);
create temporary table sudoku_schedule
(
idx int not null auto_increment primary key,
row smallint not null,
col smallint not null
);
call sudoku_init();
if p_naive then
update sudoku_work set cnt = 0 where dig = 0;
else
call sudoku_count();
end if;
insert into sudoku_schedule (row,col)
select row,col from sudoku_work where cnt is not null order by cnt desc;
begin
declare v_scounter bigint default 0;
declare v_i smallint default 1;
declare v_dig smallint;
declare v_schedmax smallint;
select count(*) into v_schedmax from sudoku_schedule;
more:
loop
begin
declare v_tcounter bigint default 0;
sched:
while v_i <= v_schedmax do
begin
declare v_row, v_col smallint;
select row,col into v_row,v_col from sudoku_schedule where v_i = idx;
select dig into v_dig from sudoku_work
where v_row = row and v_col = col;
case v_dig
when 0 then
set v_dig = 1;
update sudoku_work set dig = 1
where v_row = row and v_col = col;
when 9 then
if v_i > 0 then
update sudoku_work set dig = 0
where v_row = row and v_col = col;
set v_i = v_i - 1;
iterate sched;
else
select v_scounter as 'Solutions';
leave more;
end if;
else
set v_dig = v_dig + 1;
update sudoku_work set dig = v_dig
where v_row = row and v_col = col;
end case;
set v_tcounter = v_tcounter + 1;
if not sudoku_digit_ok(v_row, v_col, v_dig) then
iterate sched;
end if;
set v_i = v_i + 1;
end;
end while sched;
select dig from sudoku_work;
select v_tcounter as 'Tests';
set v_scounter = v_scounter + 1;
if p_all and v_i > 0 then
set v_i = v_i - 1;
else
leave more;
end if;
end;
end loop more;
end;
drop temporary table sudoku_work, sudoku_schedule;
end//
delimiter ;//
# The interestings parts are where the code for the two "leave" are:
# ...
#| 26 | jump_if_not 30 (v_i@3 > 0) |
# ...
#| 30 | stmt 0 "select v_scounter as 'Solutions'" |
#| 31 | jump 45 |
# ...
#| 42 | jump_if_not 45 (p_all@1 and (v_i@3 > 0)) |
#| 43 | set v_i@3 (v_i@3 - 1) |
#| 44 | jump 14 |
#| 45 | stmt 9 "drop temporary table sudoku_work, sud..." |
#+-----+-----------------------------------------------------------------------+
# The bug appeared at position 42 (with the wrong destination).
show procedure code sudoku_solve;
drop procedure sudoku_solve;

21
sql/sp_head.cc
View File

@ -2011,6 +2011,15 @@ sp_head::show_create_function(THD *thd)
1) Mark used instructions
1.1) While doing this, shortcut jumps to jump instructions
2) Compact the code, removing unused instructions
This is the main mark and move loop; it relies on the following methods
in sp_instr and its subclasses:
opt_mark() Mark instruction as reachable (will recurse for jumps)
opt_shortcut_jump() Shortcut jumps to the final destination;
used by opt_mark().
opt_move() Update moved instruction
set_destination() Set the new destination (jump instructions only)
*/
void sp_head::optimize()
@ -2703,12 +2712,6 @@ sp_instr_hpop::print(String *str)
str->qs_append(m_count);
}
void
sp_instr_hpop::backpatch(uint dest, sp_pcontext *dst_ctx)
{
m_count= m_ctx->diff_handlers(dst_ctx);
}
/*
sp_instr_hreturn class functions
@ -2830,12 +2833,6 @@ sp_instr_cpop::print(String *str)
str->qs_append(m_count);
}
void
sp_instr_cpop::backpatch(uint dest, sp_pcontext *dst_ctx)
{
m_count= m_ctx->diff_cursors(dst_ctx);
}
/*
sp_instr_copen class functions

40
sql/sp_head.h
View File

@ -461,17 +461,34 @@ public:
virtual void backpatch(uint dest, sp_pcontext *dst_ctx)
{}
/*
Mark this instruction as reachable during optimization and return the
index to the next instruction. Jump instruction will mark their
destination too recursively.
*/
virtual uint opt_mark(sp_head *sp)
{
marked= 1;
return m_ip+1;
}
/*
Short-cut jumps to jumps during optimization. This is used by the
jump instructions' opt_mark() methods. 'start' is the starting point,
used to prevent the mark sweep from looping for ever. Return the
end destination.
*/
virtual uint opt_shortcut_jump(sp_head *sp, sp_instr *start)
{
return m_ip;
}
/*
Inform the instruction that it has been moved during optimization.
Most instructions will simply update its index, but jump instructions
must also take care of their destination pointers. Forward jumps get
pushed to the backpatch list 'ibp'.
*/
virtual void opt_move(uint dst, List<sp_instr> *ibp)
{
m_ip= dst;
@ -696,6 +713,9 @@ public:
m_dest= dest;
}
/*
Update the destination; used by the optimizer.
*/
virtual void set_destination(uint old_dest, uint new_dest)
{
if (m_dest == old_dest)
@ -739,6 +759,7 @@ public:
virtual uint opt_mark(sp_head *sp);
/* Override sp_instr_jump's shortcut; we stop here */
virtual uint opt_shortcut_jump(sp_head *sp, sp_instr *start)
{
return m_ip;
@ -822,6 +843,7 @@ public:
virtual uint opt_mark(sp_head *sp);
/* Override sp_instr_jump's shortcut; we stop here. */
virtual uint opt_shortcut_jump(sp_head *sp, sp_instr *start)
{
return m_ip;
@ -859,15 +881,6 @@ public:
virtual void print(String *str);
virtual void backpatch(uint dest, sp_pcontext *dst_ctx);
virtual uint opt_mark(sp_head *sp)
{
if (m_count)
marked= 1;
return m_ip+1;
}
private:
uint m_count;
@ -953,15 +966,6 @@ public:
virtual void print(String *str);
virtual void backpatch(uint dest, sp_pcontext *dst_ctx);
virtual uint opt_mark(sp_head *sp)
{
if (m_count)
marked= 1;
return m_ip+1;
}
private:
uint m_count;

17
sql/sql_yacc.yy
View File

@ -2064,17 +2064,16 @@ sp_proc_stmt:
}
else
{
uint ip= sp->instructions();
sp_instr_jump *i;
sp_instr_hpop *ih;
sp_instr_cpop *ic;
uint ip= sp->instructions();
uint n;
ih= new sp_instr_hpop(ip++, ctx, 0);
sp->push_backpatch(ih, lab);
sp->add_instr(ih);
ic= new sp_instr_cpop(ip++, ctx, 0);
sp->push_backpatch(ic, lab);
sp->add_instr(ic);
n= ctx->diff_handlers(lab->ctx);
if (n)
sp->add_instr(new sp_instr_hpop(ip++, ctx, n));
n= ctx->diff_cursors(lab->ctx);
if (n)
sp->add_instr(new sp_instr_cpop(ip++, ctx, n));
i= new sp_instr_jump(ip, ctx);
sp->push_backpatch(i, lab); /* Jumping forward */
sp->add_instr(i);