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authorVarun Gupta <varun.gupta@mariadb.com>2020-06-10 18:42:47 +0530
committerVarun Gupta <varun.gupta@mariadb.com>2020-06-10 18:45:34 +0530
commit9d1809640149fb5b4ce44d1716432726ae085975 (patch)
treefe3b63f76b4bf46d3a44da4d2e5d8213baae8226
parent648b54746c2dbad98f3e09609e1217be918286dd (diff)
downloadmariadb-git-10.5-mdev22819.tar.gz
MDEV-22819: Wrong result or Assertion `ix > 0' failed in read_to_buffer upon select with GROUP BY and GROUP_CONCAT10.5-mdev22819
In the merge_buffers phase for sorting, the sort buffer size is divided between the number of chunks. The chunks have a start and end position (m_buffer_start and m_buffer_end). Then we read the as many records that fit in this buffer for a chunk of the file. The issue here was we were resetting the end of buffer(m_buffer_end) to the number of bytes that was read, this was causing a problem because with dynamic size of sort keys it is possible that later we would not be able to accommodate even one key inside a chunk of file. So the fix was to not reset the end of buffer for a chunk of file.
-rw-r--r--mysql-test/main/order_by.result58
-rw-r--r--mysql-test/main/order_by.test36
-rw-r--r--sql/filesort.cc8
-rw-r--r--sql/uniques.cc10
4 files changed, 106 insertions, 6 deletions
diff --git a/mysql-test/main/order_by.result b/mysql-test/main/order_by.result
index c750b5ca10c..26e42e4d6f9 100644
--- a/mysql-test/main/order_by.result
+++ b/mysql-test/main/order_by.result
@@ -3965,4 +3965,62 @@ a
1
0
DROP TABLE t1;
+#
+# MDEV-22819:Wrong result or Assertion `ix > 0' failed in read_to_buffer upon select
+# with GROUP BY and GROUP_CONCAT
+#
+CREATE TABLE t1 (a VARCHAR(1000), b CHAR(1));
+INSERT INTO t1 VALUES
+(REPEAT('a',1000),'a'),(REPEAT('t',932),'t'),('x',NULL),('x',NULL),
+(REPEAT('z',298),'z'),(REPEAT('p',1000),'p'),(REPEAT('k',468),'k'),
+(REPEAT('c',1000),'c'),(REPEAT('o',648),'o'),('x',NULL),('x',NULL),
+(REPEAT('c',258),'c'),(REPEAT('t',414),'t'),(REPEAT('f',966),'f'),
+(REPEAT('y',746),'y'),(REPEAT('f',1000),'f');
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+SET @save_sort_buffer_size= @@sort_buffer_size;
+SET sort_buffer_size= 16384;
+SELECT LEFT(a,1), GROUP_CONCAT(b) FROM t1 GROUP BY a;
+LEFT(a,1) GROUP_CONCAT(b)
+a a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a
+c c,c,c,c,c,c,c,c,c,c,c,c,c,c,c,c
+c c,c,c,c,c,c,c,c,c,c,c,c,c,c,c,c
+f f,f,f,f,f,f,f,f,f,f,f,f,f,f,f,f
+f f,f,f,f,f,f,f,f,f,f,f,f,f,f,f,f
+k k,k,k,k,k,k,k,k,k,k,k,k,k,k,k,k
+o o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o
+p p,p,p,p,p,p,p,p,p,p,p,p,p,p,p,p
+t t,t,t,t,t,t,t,t,t,t,t,t,t,t,t,t
+t t,t,t,t,t,t,t,t,t,t,t,t,t,t,t,t
+x NULL
+y y,y,y,y,y,y,y,y,y,y,y,y,y,y,y,y
+z z,z,z,z,z,z,z,z,z,z,z,z,z,z,z,z
+SELECT SUBSTR(a,1,1), LENGTH(a), GROUP_CONCAT(b), COUNT(*) FROM t1 GROUP BY a;
+SUBSTR(a,1,1) LENGTH(a) GROUP_CONCAT(b) COUNT(*)
+a 1000 a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a 16
+c 258 c,c,c,c,c,c,c,c,c,c,c,c,c,c,c,c 16
+c 1000 c,c,c,c,c,c,c,c,c,c,c,c,c,c,c,c 16
+f 966 f,f,f,f,f,f,f,f,f,f,f,f,f,f,f,f 16
+f 1000 f,f,f,f,f,f,f,f,f,f,f,f,f,f,f,f 16
+k 468 k,k,k,k,k,k,k,k,k,k,k,k,k,k,k,k 16
+o 648 o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o 16
+p 1000 p,p,p,p,p,p,p,p,p,p,p,p,p,p,p,p 16
+t 414 t,t,t,t,t,t,t,t,t,t,t,t,t,t,t,t 16
+t 932 t,t,t,t,t,t,t,t,t,t,t,t,t,t,t,t 16
+x 1 NULL 64
+y 746 y,y,y,y,y,y,y,y,y,y,y,y,y,y,y,y 16
+z 298 z,z,z,z,z,z,z,z,z,z,z,z,z,z,z,z 16
+SET @@sort_buffer_size= @save_sort_buffer_size;
+DROP TABLE t1;
+CREATE TABLE t1(a VARCHAR(1027), b INT);
+INSERT INTO t1 SELECT seq, seq from seq_1_to_34;
+SET @save_tmp_memory_table_size= @@tmp_memory_table_size;
+SET tmp_memory_table_size= 1056*2;
+SELECT COUNT(DISTINCT a) FROM t1;
+COUNT(DISTINCT a)
+34
+SET @@tmp_memory_table_size= @save_tmp_memory_table_size;
+DROP TABLE t1;
# End of 10.5 tests
diff --git a/mysql-test/main/order_by.test b/mysql-test/main/order_by.test
index c78add674ba..be4a3e4253e 100644
--- a/mysql-test/main/order_by.test
+++ b/mysql-test/main/order_by.test
@@ -2465,4 +2465,40 @@ SELECT * FROM t1 ORDER BY CONVERT(AES_ENCRYPT(1,a), CHAR(4));
--enable_warnings
DROP TABLE t1;
+--echo #
+--echo # MDEV-22819:Wrong result or Assertion `ix > 0' failed in read_to_buffer upon select
+--echo # with GROUP BY and GROUP_CONCAT
+--echo #
+
+CREATE TABLE t1 (a VARCHAR(1000), b CHAR(1));
+
+INSERT INTO t1 VALUES
+ (REPEAT('a',1000),'a'),(REPEAT('t',932),'t'),('x',NULL),('x',NULL),
+ (REPEAT('z',298),'z'),(REPEAT('p',1000),'p'),(REPEAT('k',468),'k'),
+ (REPEAT('c',1000),'c'),(REPEAT('o',648),'o'),('x',NULL),('x',NULL),
+ (REPEAT('c',258),'c'),(REPEAT('t',414),'t'),(REPEAT('f',966),'f'),
+ (REPEAT('y',746),'y'),(REPEAT('f',1000),'f');
+
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+
+SET @save_sort_buffer_size= @@sort_buffer_size;
+SET sort_buffer_size= 16384;
+SELECT LEFT(a,1), GROUP_CONCAT(b) FROM t1 GROUP BY a;
+SELECT SUBSTR(a,1,1), LENGTH(a), GROUP_CONCAT(b), COUNT(*) FROM t1 GROUP BY a;
+
+SET @@sort_buffer_size= @save_sort_buffer_size;
+DROP TABLE t1;
+
+CREATE TABLE t1(a VARCHAR(1027), b INT);
+INSERT INTO t1 SELECT seq, seq from seq_1_to_34;
+SET @save_tmp_memory_table_size= @@tmp_memory_table_size;
+SET tmp_memory_table_size= 1056*2;
+SELECT COUNT(DISTINCT a) FROM t1;
+SET @@tmp_memory_table_size= @save_tmp_memory_table_size;
+DROP TABLE t1;
+
+
--echo # End of 10.5 tests
diff --git a/sql/filesort.cc b/sql/filesort.cc
index 6fa9b192655..ac43c96b0e0 100644
--- a/sql/filesort.cc
+++ b/sql/filesort.cc
@@ -1845,17 +1845,15 @@ bool merge_buffers(Sort_param *param, IO_CACHE *from_file,
offsetof(Merge_chunk,m_current_key), 0,
(queue_compare) cmp, first_cmp_arg, 0, 0)))
DBUG_RETURN(1); /* purecov: inspected */
+ const size_t chunk_sz = (sort_buffer.size()/((uint) (Tb-Fb) +1));
for (buffpek= Fb ; buffpek <= Tb ; buffpek++)
{
- buffpek->set_buffer(strpos,
- strpos + (sort_buffer.size()/((uint) (Tb-Fb) +1)));
-
+ buffpek->set_buffer(strpos, strpos + chunk_sz);
buffpek->set_max_keys(maxcount);
bytes_read= read_to_buffer(from_file, buffpek, param, packed_format);
if (unlikely(bytes_read == (ulong) -1))
goto err; /* purecov: inspected */
- strpos+= bytes_read;
- buffpek->set_buffer_end(strpos);
+ strpos+= chunk_sz;
// If less data in buffers than expected
buffpek->set_max_keys(buffpek->mem_count());
queue_insert(&queue, (uchar*) buffpek);
diff --git a/sql/uniques.cc b/sql/uniques.cc
index 60918ea534e..f5d85bbb5cc 100644
--- a/sql/uniques.cc
+++ b/sql/uniques.cc
@@ -735,6 +735,13 @@ bool Unique::merge(TABLE *table, uchar *buff, size_t buff_size,
sort_param.cmp_context.key_compare= tree.compare;
sort_param.cmp_context.key_compare_arg= tree.custom_arg;
+ /*
+ We need to remove the size allocated for the unique bufffer.
+ The sort_buffer_size is:
+ MY_MAX(MERGEBUFF2+1, max_in_memory_size/full_size+1) * full_size;
+ */
+ buff_size-= full_size;
+
/* Merge the buffers to one file, removing duplicates */
if (merge_many_buff(&sort_param,
Bounds_checked_array<uchar>(buff, buff_size),
@@ -802,7 +809,8 @@ bool Unique::get(TABLE *table)
/* Not enough memory; Save the result to file && free memory used by tree */
if (flush())
DBUG_RETURN(1);
- size_t buff_sz= (max_in_memory_size / full_size + 1) * full_size;
+ size_t buff_sz= MY_MAX(MERGEBUFF2+1, max_in_memory_size/full_size+1) * full_size;
+
if (!(sort_buffer= (uchar*) my_malloc(key_memory_Unique_sort_buffer, buff_sz,
MYF(MY_THREAD_SPECIFIC|MY_WME))))
DBUG_RETURN(1);