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Fix for BUG#4177:

Browse Source 
* Make index merge quick selects code allow perform several scans.
 * Delay additional handler objects creation till row retrieval is started.


include/queues.h:
  Added trivial queue_remove_all macro
mysql-test/r/index_merge.result:
  Testcase for BUG#4177
mysql-test/t/index_merge.test:
  Testcase for BUG#4177
sql/opt_range.cc:
  Fix for BUG#4177: 
   * For any quick select, row retrieval can be performed several times. Now all index_merge quick selects code handles such cases properly.
   * In QUICK_INDEX_MERGE_SELECT we use one handler object for all merged scans, and it was possible that in 
      destructor several cleanup functions were called 
   * Additionally
    - Removed redundant QUICK_INDEX_MERGE_SELECT members.
    - Now QUICK_ROR_*_SELECTs create additional handler objects only when row retrieval is started
      So if join optimizer chooses other access method, we don't create/delete handlers.
This commit is contained in:
unknown
2004-11-21 11:51:19 +03:00
parent 6763a1da76
commit febda72f62
5 changed files with 188 additions and 47 deletions
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1
include/queues.h
View File

@ -53,6 +53,7 @@ int resize_queue(QUEUE *queue, uint max_elements);
void delete_queue(QUEUE *queue);
void queue_insert(QUEUE *queue,byte *element);
byte *queue_remove(QUEUE *queue,uint idx);
#define queue_remove_all(queue) { (queue)->elements= 0; }
void _downheap(QUEUE *queue,uint idx);
void queue_fix(QUEUE *queue);
#define is_queue_inited(queue) ((queue)->root != 0)

53
mysql-test/r/index_merge.result
View File

@ -1,4 +1,4 @@
drop table if exists t0, t1, t2, t3,t4;
drop table if exists t0, t1, t2, t3, t4;
create table t0
(
key1 int not null,
@ -335,4 +335,55 @@ key1 key2 key3 key4 key5 key6 key7 key8
select count(*) from t0;
count(*)
1021
drop table t4;
create table t4 (a int);
insert into t4 values (1),(4),(3);
set @save_join_buffer_size=@@join_buffer_size;
set join_buffer_size= 4000;
show variables like 'join_buffer_size';
Variable_name Value
join_buffer_size 8228
explain select max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5)
from t0 as A force index(i1,i2), t0 as B force index (i1,i2)
where (A.key1 < 500000 or A.key2 < 3)
and (B.key1 < 500000 or B.key2 < 3);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE A index_merge i1,i2 i1,i2 4,4 NULL 1016 Using sort_union(i1,i2); Using where
1 SIMPLE B index_merge i1,i2 i1,i2 4,4 NULL 1016 Using sort_union(i1,i2); Using where
select max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5)
from t0 as A force index(i1,i2), t0 as B force index (i1,i2)
where (A.key1 < 500000 or A.key2 < 3)
and (B.key1 < 500000 or B.key2 < 3);
max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5)
10240
update t0 set key1=1;
explain select max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5)
from t0 as A force index(i1,i2), t0 as B force index (i1,i2)
where (A.key1 = 1 or A.key2 = 1)
and (B.key1 = 1 or B.key2 = 1);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE A index_merge i1,i2 i1,i2 4,4 NULL 1020 Using union(i1,i2); Using where
1 SIMPLE B index_merge i1,i2 i1,i2 4,4 NULL 1020 Using union(i1,i2); Using where
select max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5)
from t0 as A force index(i1,i2), t0 as B force index (i1,i2)
where (A.key1 = 1 or A.key2 = 1)
and (B.key1 = 1 or B.key2 = 1);
max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5)
8194
alter table t0 add filler1 char(200), add filler2 char(200), add filler3 char(200);
update t0 set key2=1, key3=1, key4=1, key5=1,key6=1,key7=1 where key7 < 500;
explain select max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5)
from t0 as A, t0 as B
where (A.key1 = 1 and A.key2 = 1 and A.key3 = 1 and A.key4=1 and A.key5=1 and A.key6=1 and A.key7 = 1 or A.key8=1)
and (B.key1 = 1 and B.key2 = 1 and B.key3 = 1 and B.key4=1 and B.key5=1 and B.key6=1 and B.key7 = 1 or B.key8=1);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE A index_merge i1,i2,i3,i4,i5,i6,i7,i8 i2,i3,i4,i5,i6,i8 4,4,4,4,4,4 NULL 16 Using union(intersect(i2,i3,i4,i5,i6),i8); Using where
1 SIMPLE B index_merge i1,i2,i3,i4,i5,i6,i7,i8 i2,i3,i4,i5,i6,i8 4,4,4,4,4,4 NULL 16 Using union(intersect(i2,i3,i4,i5,i6),i8); Using where
select max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5)
from t0 as A, t0 as B
where (A.key1 = 1 and A.key2 = 1 and A.key3 = 1 and A.key4=1 and A.key5=1 and A.key6=1 and A.key7 = 1 or A.key8=1)
and (B.key1 = 1 and B.key2 = 1 and B.key3 = 1 and B.key4=1 and B.key5=1 and B.key6=1 and B.key7 = 1 or B.key8=1);
max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5)
8186
set join_buffer_size= @save_join_buffer_size;
drop table t0, t1, t2, t3, t4;

49
mysql-test/t/index_merge.test
View File

@ -1,9 +1,8 @@
#
# Index merge tests
#
--disable_warnings
drop table if exists t0, t1, t2, t3,t4;
drop table if exists t0, t1, t2, t3, t4;
--enable_warnings
# Create and fill a table with simple keys
@ -278,4 +277,48 @@ delete from t0 where key1 < 3 or key2 < 4;
select * from t0 where key1 < 3 or key2 < 4;
select count(*) from t0;
drop table t0, t1, t2, t3, t4;
# Test for BUG#4177
drop table t4;
create table t4 (a int);
insert into t4 values (1),(4),(3);
set @save_join_buffer_size=@@join_buffer_size;
set join_buffer_size= 4000;
show variables like 'join_buffer_size';
explain select max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5)
from t0 as A force index(i1,i2), t0 as B force index (i1,i2)
where (A.key1 < 500000 or A.key2 < 3)
and (B.key1 < 500000 or B.key2 < 3);
select max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5)
from t0 as A force index(i1,i2), t0 as B force index (i1,i2)
where (A.key1 < 500000 or A.key2 < 3)
and (B.key1 < 500000 or B.key2 < 3);
update t0 set key1=1;
explain select max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5)
from t0 as A force index(i1,i2), t0 as B force index (i1,i2)
where (A.key1 = 1 or A.key2 = 1)
and (B.key1 = 1 or B.key2 = 1);
select max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5)
from t0 as A force index(i1,i2), t0 as B force index (i1,i2)
where (A.key1 = 1 or A.key2 = 1)
and (B.key1 = 1 or B.key2 = 1);
alter table t0 add filler1 char(200), add filler2 char(200), add filler3 char(200);
update t0 set key2=1, key3=1, key4=1, key5=1,key6=1,key7=1 where key7 < 500;
explain select max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5)
from t0 as A, t0 as B
where (A.key1 = 1 and A.key2 = 1 and A.key3 = 1 and A.key4=1 and A.key5=1 and A.key6=1 and A.key7 = 1 or A.key8=1)
and (B.key1 = 1 and B.key2 = 1 and B.key3 = 1 and B.key4=1 and B.key5=1 and B.key6=1 and B.key7 = 1 or B.key8=1);
select max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5)
from t0 as A, t0 as B
where (A.key1 = 1 and A.key2 = 1 and A.key3 = 1 and A.key4=1 and A.key5=1 and A.key6=1 and A.key7 = 1 or A.key8=1)
and (B.key1 = 1 and B.key2 = 1 and B.key3 = 1 and B.key4=1 and B.key5=1 and B.key6=1 and B.key7 = 1 or B.key8=1);
set join_buffer_size= @save_join_buffer_size;
# Test for BUG#4177 ends
drop table t0, t1, t2, t3, t4;

114
sql/opt_range.cc
View File

@ -777,8 +777,7 @@ QUICK_RANGE_SELECT::~QUICK_RANGE_SELECT()
QUICK_INDEX_MERGE_SELECT::QUICK_INDEX_MERGE_SELECT(THD *thd_param,
TABLE *table)
:cur_quick_it(quick_selects),pk_quick_select(NULL),unique(NULL),
thd(thd_param)
:pk_quick_select(NULL), thd(thd_param)
{
DBUG_ENTER("QUICK_INDEX_MERGE_SELECT::QUICK_INDEX_MERGE_SELECT");
index= MAX_KEY;
@ -790,17 +789,14 @@ QUICK_INDEX_MERGE_SELECT::QUICK_INDEX_MERGE_SELECT(THD *thd_param,
int QUICK_INDEX_MERGE_SELECT::init()
{
cur_quick_it.rewind();
cur_quick_select= cur_quick_it++;
return 0;
DBUG_ENTER("QUICK_INDEX_MERGE_SELECT::init");
DBUG_RETURN(0);
}
int QUICK_INDEX_MERGE_SELECT::reset()
{
int result;
DBUG_ENTER("QUICK_INDEX_MERGE_SELECT::reset");
result= cur_quick_select->reset() || prepare_unique();
DBUG_RETURN(result);
DBUG_RETURN(read_keys_and_merge());
}
bool
@ -820,8 +816,12 @@ QUICK_INDEX_MERGE_SELECT::push_quick_back(QUICK_RANGE_SELECT *quick_sel_range)
QUICK_INDEX_MERGE_SELECT::~QUICK_INDEX_MERGE_SELECT()
{
List_iterator_fast<QUICK_RANGE_SELECT> quick_it(quick_selects);
QUICK_RANGE_SELECT* quick;
DBUG_ENTER("QUICK_INDEX_MERGE_SELECT::~QUICK_INDEX_MERGE_SELECT");
delete unique;
quick_it.rewind();
while ((quick= quick_it++))
quick->file= NULL;
quick_selects.delete_elements();
delete pk_quick_select;
free_root(&alloc,MYF(0));
@ -833,7 +833,8 @@ QUICK_ROR_INTERSECT_SELECT::QUICK_ROR_INTERSECT_SELECT(THD *thd_param,
TABLE *table,
bool retrieve_full_rows,
MEM_ROOT *parent_alloc)
: cpk_quick(NULL), thd(thd_param), need_to_fetch_row(retrieve_full_rows)
: cpk_quick(NULL), thd(thd_param), need_to_fetch_row(retrieve_full_rows),
scans_inited(false)
{
index= MAX_KEY;
head= table;
@ -859,8 +860,9 @@ QUICK_ROR_INTERSECT_SELECT::QUICK_ROR_INTERSECT_SELECT(THD *thd_param,
int QUICK_ROR_INTERSECT_SELECT::init()
{
/* Check if last_rowid was successfully allocated in ctor */
return !last_rowid;
DBUG_ENTER("QUICK_ROR_INTERSECT_SELECT::init");
/* Check if last_rowid was successfully allocated in ctor */
DBUG_RETURN(!last_rowid);
}
@ -953,7 +955,7 @@ int QUICK_ROR_INTERSECT_SELECT::init_ror_merged_scan(bool reuse_handler)
DBUG_ENTER("QUICK_ROR_INTERSECT_SELECT::init_ror_merged_scan");
/* Initialize all merged "children" quick selects */
DBUG_ASSERT(!(need_to_fetch_row && !reuse_handler));
DBUG_ASSERT(!need_to_fetch_row || reuse_handler);
if (!need_to_fetch_row && reuse_handler)
{
quick= quick_it++;
@ -995,7 +997,14 @@ int QUICK_ROR_INTERSECT_SELECT::init_ror_merged_scan(bool reuse_handler)
int QUICK_ROR_INTERSECT_SELECT::reset()
{
DBUG_ENTER("QUICK_ROR_INTERSECT_SELECT::reset");
DBUG_RETURN(init_ror_merged_scan(TRUE));
if (!scans_inited && init_ror_merged_scan(TRUE))
DBUG_RETURN(1);
scans_inited= true;
List_iterator_fast<QUICK_RANGE_SELECT> it(quick_selects);
QUICK_RANGE_SELECT *quick;
while ((quick= it++))
quick->reset();
DBUG_RETURN(0);
}
@ -1034,7 +1043,7 @@ QUICK_ROR_INTERSECT_SELECT::~QUICK_ROR_INTERSECT_SELECT()
QUICK_ROR_UNION_SELECT::QUICK_ROR_UNION_SELECT(THD *thd_param,
TABLE *table)
:thd(thd_param)
: thd(thd_param), scans_inited(false)
{
index= MAX_KEY;
head= table;
@ -1057,18 +1066,19 @@ QUICK_ROR_UNION_SELECT::QUICK_ROR_UNION_SELECT(THD *thd_param,
int QUICK_ROR_UNION_SELECT::init()
{
DBUG_ENTER("QUICK_ROR_UNION_SELECT::init");
if (init_queue(&queue, quick_selects.elements, 0,
FALSE , QUICK_ROR_UNION_SELECT::queue_cmp,
(void*) this))
{
bzero(&queue, sizeof(QUEUE));
return 1;
DBUG_RETURN(1);
}
if (!(cur_rowid= (byte*)alloc_root(&alloc, 2*head->file->ref_length)))
return 1;
DBUG_RETURN(1);
prev_rowid= cur_rowid + head->file->ref_length;
return 0;
DBUG_RETURN(0);
}
@ -1106,6 +1116,18 @@ int QUICK_ROR_UNION_SELECT::reset()
int error;
DBUG_ENTER("QUICK_ROR_UNION_SELECT::reset");
have_prev_rowid= FALSE;
if (!scans_inited)
{
QUICK_SELECT_I *quick;
List_iterator_fast<QUICK_SELECT_I> it(quick_selects);
while ((quick= it++))
{
if (quick->init_ror_merged_scan(FALSE))
DBUG_RETURN(1);
}
scans_inited= true;
}
queue_remove_all(&queue);
/*
Initialize scans for merged quick selects and put all merged quick
selects into the queue.
@ -1113,7 +1135,7 @@ int QUICK_ROR_UNION_SELECT::reset()
List_iterator_fast<QUICK_SELECT_I> it(quick_selects);
while ((quick= it++))
{
if (quick->init_ror_merged_scan(FALSE))
if (quick->reset())
DBUG_RETURN(1);
if ((error= quick->get_next()))
{
@ -1591,7 +1613,6 @@ int SQL_SELECT::test_quick_select(THD *thd, key_map keys_to_use,
DBUG_PRINT("enter",("keys_to_use: %lu prev_tables: %lu const_tables: %lu",
keys_to_use.to_ulonglong(), (ulong) prev_tables,
(ulong) const_tables));
delete quick;
quick=0;
needed_reg.clear_all();
@ -5545,22 +5566,29 @@ err:
/*
Fetch all row ids into unique.
Perform key scans for all used indexes (except CPK), get rowids and merge
them into an ordered non-recurrent sequence of rowids.
The merge/duplicate removal is performed using Unique class. We put all
rowids into Unique, get the sorted sequence and destroy the Unique.
If table has a clustered primary key that covers all rows (TRUE for bdb
and innodb currently) and one of the index_merge scans is a scan on PK,
then
primary key scan rowids are not put into Unique and also
rows that will be retrieved by PK scan are not put into Unique
rows that will be retrieved by PK scan are not put into Unique and
primary key scan is not performed here, it is performed later separately.
RETURN
0 OK
other error
*/
int QUICK_INDEX_MERGE_SELECT::prepare_unique()
int QUICK_INDEX_MERGE_SELECT::read_keys_and_merge()
{
List_iterator_fast<QUICK_RANGE_SELECT> cur_quick_it(quick_selects);
QUICK_RANGE_SELECT* cur_quick;
int result;
Unique *unique;
DBUG_ENTER("QUICK_INDEX_MERGE_SELECT::prepare_unique");
/* We're going to just read rowids. */
@ -5575,7 +5603,17 @@ int QUICK_INDEX_MERGE_SELECT::prepare_unique()
*/
head->file->extra(HA_EXTRA_RETRIEVE_ALL_COLS);
cur_quick_select->init();
cur_quick_it.rewind();
cur_quick= cur_quick_it++;
DBUG_ASSERT(cur_quick);
/*
We reuse the same instance of handler so we need to call both init and
reset here.
*/
if (cur_quick->init())
DBUG_RETURN(1);
cur_quick->reset();
unique= new Unique(refpos_order_cmp, (void *)head->file,
head->file->ref_length,
@ -5584,24 +5622,28 @@ int QUICK_INDEX_MERGE_SELECT::prepare_unique()
DBUG_RETURN(1);
for (;;)
{
while ((result= cur_quick_select->get_next()) == HA_ERR_END_OF_FILE)
while ((result= cur_quick->get_next()) == HA_ERR_END_OF_FILE)
{
cur_quick_select->range_end();
cur_quick_select= cur_quick_it++;
if (!cur_quick_select)
cur_quick->range_end();
cur_quick= cur_quick_it++;
if (!cur_quick)
break;
if (cur_quick_select->init())
if (cur_quick->file->inited != handler::NONE)
cur_quick->file->ha_index_end();
if (cur_quick->init())
DBUG_RETURN(1);
/* QUICK_RANGE_SELECT::reset never fails */
cur_quick_select->reset();
cur_quick->reset();
}
if (result)
{
if (result != HA_ERR_END_OF_FILE)
{
cur_quick->range_end();
DBUG_RETURN(result);
}
break;
}
@ -5612,8 +5654,8 @@ int QUICK_INDEX_MERGE_SELECT::prepare_unique()
if (pk_quick_select && pk_quick_select->row_in_ranges())
continue;
cur_quick_select->file->position(cur_quick_select->record);
result= unique->unique_add((char*)cur_quick_select->file->ref);
cur_quick->file->position(cur_quick->record);
result= unique->unique_add((char*)cur_quick->file->ref);
if (result)
DBUG_RETURN(1);
@ -5621,6 +5663,7 @@ int QUICK_INDEX_MERGE_SELECT::prepare_unique()
/* ok, all row ids are in Unique */
result= unique->get(head);
delete unique;
doing_pk_scan= FALSE;
/* start table scan */
init_read_record(&read_record, thd, head, (SQL_SELECT*) 0, 1, 1);
@ -5660,6 +5703,7 @@ int QUICK_INDEX_MERGE_SELECT::get_next()
doing_pk_scan= TRUE;
if ((result= pk_quick_select->init()))
DBUG_RETURN(result);
pk_quick_select->reset();
DBUG_RETURN(pk_quick_select->get_next());
}
}

18
sql/opt_range.h
View File

@ -127,7 +127,8 @@ public:
reset() should be called when it is certain that row retrieval will be
necessary. This call may do heavyweight initialization like buffering first
N records etc. If reset() call fails get_next() must not be called.
Note that reset() may be called several times if this quick select
executes in a subselect.
RETURN
0 OK
other Error code
@ -274,6 +275,10 @@ public:
next=0;
range= NULL;
cur_range= NULL;
/*
Note: in opt_range.cc there are places where it is assumed that this
function always succeeds
*/
return 0;
}
int init();
@ -388,21 +393,15 @@ public:
/* range quick selects this index_merge read consists of */
List<QUICK_RANGE_SELECT> quick_selects;
/* quick select which is currently used for rows retrieval */
List_iterator_fast<QUICK_RANGE_SELECT> cur_quick_it;
QUICK_RANGE_SELECT* cur_quick_select;
/* quick select that uses clustered primary key (NULL if none) */
QUICK_RANGE_SELECT* pk_quick_select;
/* true if this select is currently doing a clustered PK scan */
bool doing_pk_scan;
Unique *unique;
MEM_ROOT alloc;
THD *thd;
int prepare_unique();
int read_keys_and_merge();
/* used to get rows collected in Unique */
READ_RECORD read_record;
@ -465,6 +464,8 @@ public:
MEM_ROOT alloc; /* Memory pool for this and merged quick selects data. */
THD *thd; /* current thread */
bool need_to_fetch_row; /* if true, do retrieve full table records. */
/* in top-level quick select, true if merged scans where initialized */
bool scans_inited;
};
@ -514,6 +515,7 @@ public:
uint rowid_length; /* table rowid length */
private:
static int queue_cmp(void *arg, byte *val1, byte *val2);
bool scans_inited;
};