Merge 10.1 into 10.2

3 files changed, 10 insertions, 4 deletions

diff --git a/sql/field.cc b/sql/field.cc
index d1bd5860f06..1ea7b30f85d 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -3507,10 +3507,9 @@ int Field_new_decimal::cmp(const uchar *a,const uchar*b)
 }
 
 
-void Field_new_decimal::sort_string(uchar *buff,
-                                    uint length __attribute__((unused)))
+void Field_new_decimal::sort_string(uchar *buff, uint length)
 {
-  memcpy(buff, ptr, bin_size);
+  memcpy(buff, ptr, length);
 }
 
 
diff --git a/sql/field.h b/sql/field.h
index 3007e666ba7..d5e2cb25788 100644
--- a/sql/field.h
+++ b/sql/field.h
@@ -1218,6 +1218,13 @@ public:
 
   void make_sort_key(uchar *buff, uint length);
   virtual void make_field(Send_field *);
+
+  /*
+    Some implementations actually may write up to 8 bytes regardless of what
+    size was requested. This is due to the minimum value of the system variable
+    max_sort_length.
+  */
+
   virtual void sort_string(uchar *buff,uint length)=0;
   virtual bool optimize_range(uint idx, uint part);
   virtual void free() {}
diff --git a/sql/sys_vars.cc b/sql/sys_vars.cc
index 8eb75e49d8e..2d40943827f 100644
--- a/sql/sys_vars.cc
+++ b/sql/sys_vars.cc
@@ -2224,7 +2224,7 @@ static Sys_var_ulong Sys_max_sort_length(
        "the first max_sort_length bytes of each value are used; the rest "
        "are ignored)",
        SESSION_VAR(max_sort_length), CMD_LINE(REQUIRED_ARG),
-       VALID_RANGE(4, 8192*1024L), DEFAULT(1024), BLOCK_SIZE(1));
+       VALID_RANGE(8, 8192*1024L), DEFAULT(1024), BLOCK_SIZE(1));
 
 static Sys_var_ulong Sys_max_sp_recursion_depth(
        "max_sp_recursion_depth",