Merge 10.8 into 10.9

configure.cmake

@@ -324,7 +324,14 @@ ENDIF()
 CHECK_FUNCTION_EXISTS (accept4 HAVE_ACCEPT4)
 CHECK_FUNCTION_EXISTS (access HAVE_ACCESS)
 CHECK_FUNCTION_EXISTS (alarm HAVE_ALARM)
-CHECK_FUNCTION_EXISTS (aligned_alloc HAVE_ALIGNED_ALLOC)
+IF (CMAKE_SYSTEM_NAME MATCHES "Linux" AND NOT WITH_ASAN)
+  # When an old custom memory allocator library is used, aligned_alloc()
+  # could invoke the built-in allocator in libc, not matching
+  # the overriden free() in the custom memory allocator.
+  SET(HAVE_ALIGNED_ALLOC 0)
+ELSE()
+  CHECK_FUNCTION_EXISTS (aligned_alloc HAVE_ALIGNED_ALLOC)
+ENDIF()
 SET(HAVE_ALLOCA 1)
 CHECK_FUNCTION_EXISTS (backtrace HAVE_BACKTRACE)
 CHECK_FUNCTION_EXISTS (backtrace_symbols HAVE_BACKTRACE_SYMBOLS)

include/aligned.h

@@ -14,12 +14,19 @@
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1335  USA */
 
+#ifdef HAVE_ALIGNED_ALLOC
+#elif defined __linux__
+# include <malloc.h>
+#endif
+
 inline void *aligned_malloc(size_t size, size_t alignment)
 {
 #ifdef _WIN32
   return _aligned_malloc(size, alignment);
 #elif defined HAVE_ALIGNED_ALLOC
   return aligned_alloc(alignment, size);
+#elif defined __linux__
+  return memalign(alignment, size);
 #else
   void *result;
   if (posix_memalign(&result, alignment, size))

mysql-test/main/statistics_json.result

@@ -8322,3 +8322,34 @@ histogram
   ]
 }
 drop table t1;
+#
+# MDEV-28882: Assertion `tmp >= 0' failed in best_access_path
+#
+CREATE TABLE t1 (a varchar(1));
+INSERT INTO t1 VALUES ('o'),('s'),('j'),('s'),('y'),('s'),('l'),
+('q'),('x'),('m'),('t'),('d'),('v'),('j'),('p'),('t'),('b'),('q');
+set histogram_type=json_hb;
+analyze table t1 persistent for all;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+# filtered must not be negative:
+explain format=json select * from t1 where a > 'y';
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "ALL",
+          "rows": 18,
+          "filtered": 5.555555344,
+          "attached_condition": "t1.a > 'y'"
+        }
+      }
+    ]
+  }
+}
+drop table t1;

mysql-test/main/statistics_json.test

@@ -460,3 +460,19 @@ from mysql.column_stats where table_name='t1' and db_name=database();
 
 drop table t1;
 
+--echo #
+--echo # MDEV-28882: Assertion `tmp >= 0' failed in best_access_path
+--echo #
+
+CREATE TABLE t1 (a varchar(1));
+
+INSERT INTO t1 VALUES ('o'),('s'),('j'),('s'),('y'),('s'),('l'),
+  ('q'),('x'),('m'),('t'),('d'),('v'),('j'),('p'),('t'),('b'),('q');
+
+set histogram_type=json_hb;
+analyze table t1 persistent for all;
+--echo # filtered must not be negative:
+explain format=json select * from t1 where a > 'y';
+
+drop table t1;
+

sql/opt_histogram_json.cc

@@ -959,9 +959,16 @@ std::string& Histogram_json_hb::get_end_value(int idx)
   @param field    The table field histogram is for.  We don't care about the
                   field's current value, we only need its virtual functions to
                   perform various operations
-
   @param min_endp Left endpoint, or NULL if there is none
   @param max_endp Right endpoint, or NULL if there is none
+  @param avg_sel  Average selectivity of "field=const" equality for this field
+
+  @return
+     Range selectivity: a number between 0.0 and 1.0.
+
+  @note
+     This may return 0.0. Adjustments to avoid multiply-by-zero meltdown are
+     made elsewhere.
 */
 
 double Histogram_json_hb::range_selectivity(Field *field, key_range *min_endp,
@@ -1062,6 +1069,18 @@ double Histogram_json_hb::range_selectivity(Field *field, key_range *min_endp,
   else
     max= 1.0;
 
+  if (min > max)
+  {
+    /*
+      This can happen due to rounding errors.
+
+      What is the acceptable error size? Json_writer::add_double() uses
+      %.11lg format. This gives 9 digits after the dot. A histogram may have
+      hundreds of buckets, let's multiply the error by 1000. 9-3=6
+    */
+    DBUG_ASSERT(max < min + 1e-6);
+    max= min;
+  }
   return max - min;
 }
 

storage/innobase/buf/buf0flu.cc

@@ -544,9 +544,19 @@ static void buf_tmp_reserve_compression_buf(buf_tmp_buffer_t* slot)
   buffer be bigger than input buffer. Adjust the allocated size. */
   ulint size= srv_page_size;
   if (provider_service_lzo->is_loaded)
-    size+= LZO1X_1_15_MEM_COMPRESS;
+  {
+    size= LZO1X_1_15_MEM_COMPRESS;
+#ifdef HAVE_ALIGNED_ALLOC
+    size= MY_ALIGN(size, srv_page_size);
+#endif
+  }
   else if (provider_service_snappy->is_loaded)
+  {
     size= snappy_max_compressed_length(size);
+#ifdef HAVE_ALIGNED_ALLOC
+    size= MY_ALIGN(size, srv_page_size);
+#endif
+  }
   slot->comp_buf= static_cast<byte*>(aligned_malloc(size, srv_page_size));
 }
 

storage/perfschema/unittest/stub_pfs_global.h

@@ -26,6 +26,7 @@
 #include <pfs_global.h>
 #include <string.h>
 #include "aligned.h"
+#include "assume_aligned.h"
 
 bool pfs_initialized= false;
 size_t pfs_allocated_memory_size= 0;
@@ -47,9 +48,10 @@ void *pfs_malloc(PFS_builtin_memory_class *klass, size_t size, myf)
   if (--stub_alloc_fails_after_count <= 0)
     return NULL;
 
+  size= MY_ALIGN(size, CPU_LEVEL1_DCACHE_LINESIZE);
   void *ptr= aligned_malloc(size, CPU_LEVEL1_DCACHE_LINESIZE);
   if (ptr != NULL)
-    memset(ptr, 0, size);
+    memset_aligned<CPU_LEVEL1_DCACHE_LINESIZE>(ptr, 0, size);
   return ptr;
 }