Commit f8683bfb authored by igor@olga.mysql.com's avatar igor@olga.mysql.com

Fixed bug #25798.

This bug may manifest itself not only with the queries for which
the index-merge access method is chosen. It also may display
itself for queries with DISTINCT.

The bug was in how the Unique::get method used the merge_buffers
function. To compare elements in the the queue employed by
merge_buffers() it must use the buffpek_compare function rather
than the function for binary comparison. 
parent 38deea24
......@@ -676,4 +676,55 @@ INSERT INTO t1 VALUES (1);
switch to connection default
SET AUTOCOMMIT=default;
DROP TABLE t1,t2;
CREATE TABLE t1 (
id int NOT NULL auto_increment PRIMARY KEY,
b int NOT NULL,
c datetime NOT NULL,
INDEX idx_b(b),
INDEX idx_c(c)
) ENGINE=InnoDB;
CREATE TABLE t2 (
b int NOT NULL auto_increment PRIMARY KEY,
c datetime NOT NULL
) ENGINE= MyISAM;
INSERT INTO t2(c) VALUES ('2007-01-01');
INSERT INTO t2(c) SELECT c FROM t2;
INSERT INTO t2(c) SELECT c FROM t2;
INSERT INTO t2(c) SELECT c FROM t2;
INSERT INTO t2(c) SELECT c FROM t2;
INSERT INTO t2(c) SELECT c FROM t2;
INSERT INTO t2(c) SELECT c FROM t2;
INSERT INTO t2(c) SELECT c FROM t2;
INSERT INTO t2(c) SELECT c FROM t2;
INSERT INTO t2(c) SELECT c FROM t2;
INSERT INTO t2(c) SELECT c FROM t2;
INSERT INTO t1(b,c) SELECT b,c FROM t2;
UPDATE t2 SET c='2007-01-02';
INSERT INTO t1(b,c) SELECT b,c FROM t2;
UPDATE t2 SET c='2007-01-03';
INSERT INTO t1(b,c) SELECT b,c FROM t2;
set @@sort_buffer_size=8192;
SELECT COUNT(*) FROM t1;
COUNT(*)
3072
EXPLAIN
SELECT COUNT(*) FROM t1
WHERE (c >= '2007-01-02' AND c <= '2007-01-03') OR b >= 1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL idx_b,idx_c NULL NULL NULL 3263 Using where
SELECT COUNT(*) FROM t1
WHERE (c >= '2007-01-02' AND c <= '2007-01-03') OR b >= 1;
COUNT(*)
3072
EXPLAIN
SELECT COUNT(*) FROM t1 FORCE INDEX(idx_b, idx_c)
WHERE (c >= '2007-01-02' AND c <= '2007-01-03') OR b >= 1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index_merge idx_b,idx_c idx_c,idx_b 8,4 NULL 3262 Using sort_union(idx_c,idx_b); Using where
SELECT COUNT(*) FROM t1 FORCE INDEX(idx_b, idx_c)
WHERE (c >= '2007-01-02' AND c <= '2007-01-03') OR b >= 1;
COUNT(*)
3072
set @@sort_buffer_size=default;
DROP TABLE t1,t2;
End of 5.0 tests
......@@ -670,5 +670,59 @@ DISCONNECT c1;
DISCONNECT c2;
DROP TABLE t1,t2;
#
# Bug #25798: a query with forced index merge returns wrong result
#
CREATE TABLE t1 (
id int NOT NULL auto_increment PRIMARY KEY,
b int NOT NULL,
c datetime NOT NULL,
INDEX idx_b(b),
INDEX idx_c(c)
) ENGINE=InnoDB;
CREATE TABLE t2 (
b int NOT NULL auto_increment PRIMARY KEY,
c datetime NOT NULL
) ENGINE= MyISAM;
INSERT INTO t2(c) VALUES ('2007-01-01');
INSERT INTO t2(c) SELECT c FROM t2;
INSERT INTO t2(c) SELECT c FROM t2;
INSERT INTO t2(c) SELECT c FROM t2;
INSERT INTO t2(c) SELECT c FROM t2;
INSERT INTO t2(c) SELECT c FROM t2;
INSERT INTO t2(c) SELECT c FROM t2;
INSERT INTO t2(c) SELECT c FROM t2;
INSERT INTO t2(c) SELECT c FROM t2;
INSERT INTO t2(c) SELECT c FROM t2;
INSERT INTO t2(c) SELECT c FROM t2;
INSERT INTO t1(b,c) SELECT b,c FROM t2;
UPDATE t2 SET c='2007-01-02';
INSERT INTO t1(b,c) SELECT b,c FROM t2;
UPDATE t2 SET c='2007-01-03';
INSERT INTO t1(b,c) SELECT b,c FROM t2;
set @@sort_buffer_size=8192;
SELECT COUNT(*) FROM t1;
EXPLAIN
SELECT COUNT(*) FROM t1
WHERE (c >= '2007-01-02' AND c <= '2007-01-03') OR b >= 1;
SELECT COUNT(*) FROM t1
WHERE (c >= '2007-01-02' AND c <= '2007-01-03') OR b >= 1;
EXPLAIN
SELECT COUNT(*) FROM t1 FORCE INDEX(idx_b, idx_c)
WHERE (c >= '2007-01-02' AND c <= '2007-01-03') OR b >= 1;
SELECT COUNT(*) FROM t1 FORCE INDEX(idx_b, idx_c)
WHERE (c >= '2007-01-02' AND c <= '2007-01-03') OR b >= 1;
set @@sort_buffer_size=default;
DROP TABLE t1,t2;
--echo End of 5.0 tests
......@@ -1052,6 +1052,7 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
BUFFPEK *buffpek;
QUEUE queue;
qsort2_cmp cmp;
void *first_cmp_arg;
volatile THD::killed_state *killed= &current_thd->killed;
THD::killed_state not_killable;
DBUG_ENTER("merge_buffers");
......@@ -1077,9 +1078,18 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
/* The following will fire if there is not enough space in sort_buffer */
DBUG_ASSERT(maxcount!=0);
if (param->unique_buff)
{
cmp= param->compare;
first_cmp_arg= (void *) &param->cmp_context;
}
else
{
cmp= get_ptr_compare(sort_length);
first_cmp_arg= (void*) &sort_length;
}
if (init_queue(&queue, (uint) (Tb-Fb)+1, offsetof(BUFFPEK,key), 0,
(queue_compare) (cmp= get_ptr_compare(sort_length)),
(void*) &sort_length))
(queue_compare) cmp, first_cmp_arg))
DBUG_RETURN(1); /* purecov: inspected */
for (buffpek= Fb ; buffpek <= Tb ; buffpek++)
{
......@@ -1132,7 +1142,7 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
buffpek= (BUFFPEK*) queue_top(&queue);
if (cmp) // Remove duplicates
{
if (!(*cmp)(&sort_length, &(param->unique_buff),
if (!(*cmp)(first_cmp_arg, &(param->unique_buff),
(uchar**) &buffpek->key))
goto skip_duplicate;
memcpy(param->unique_buff, (uchar*) buffpek->key, rec_length);
......@@ -1184,7 +1194,7 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
*/
if (cmp)
{
if (!(*cmp)(&sort_length, &(param->unique_buff), (uchar**) &buffpek->key))
if (!(*cmp)(first_cmp_arg, &(param->unique_buff), (uchar**) &buffpek->key))
{
buffpek->key+= rec_length; // Remove duplicate
--buffpek->mem_count;
......
......@@ -50,6 +50,12 @@ typedef struct st_buffpek { /* Struktur om sorteringsbuffrarna */
ulong max_keys; /* Max keys in buffert */
} BUFFPEK;
struct BUFFPEK_COMPARE_CONTEXT
{
qsort_cmp2 key_compare;
void *key_compare_arg;
};
typedef struct st_sort_param {
uint rec_length; /* Length of sorted records */
uint sort_length; /* Length of sorted columns */
......@@ -65,6 +71,9 @@ typedef struct st_sort_param {
uchar *unique_buff;
bool not_killable;
char* tmp_buffer;
/* The fields below are used only by Unique class */
qsort2_cmp compare;
BUFFPEK_COMPARE_CONTEXT cmp_context;
} SORTPARAM;
......
......@@ -361,17 +361,12 @@ Unique::reset()
}
/*
The comparison function, passed to queue_init() in merge_walk() must
The comparison function, passed to queue_init() in merge_walk() and in
merge_buffers() when the latter is called from Uniques::get() must
use comparison function of Uniques::tree, but compare members of struct
BUFFPEK.
*/
struct BUFFPEK_COMPARE_CONTEXT
{
qsort_cmp2 key_compare;
void *key_compare_arg;
};
C_MODE_START
static int buffpek_compare(void *arg, byte *key_ptr1, byte *key_ptr2)
......@@ -630,6 +625,10 @@ bool Unique::get(TABLE *table)
sort_param.unique_buff= sort_buffer+(sort_param.keys*
sort_param.sort_length);
sort_param.compare= (qsort2_cmp) buffpek_compare;
sort_param.cmp_context.key_compare= tree.compare;
sort_param.cmp_context.key_compare_arg= tree.custom_arg;
/* Merge the buffers to one file, removing duplicates */
if (merge_many_buff(&sort_param,sort_buffer,file_ptr,&maxbuffer,&file))
goto err;
......
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