maria-developers team mailing list archive

[Alexander Barkov <bar@xxxxxxxxxxx>]

Hi Sergei,


Here's a new patch, returning DBL_MAX in case of inf.

Thanks!

On 08/08/2016 03:17 PM, Sergei Golubchik wrote:
> Hi, Alexander!
>
> On Aug 03, Alexander Barkov wrote:
> > diff --git a/sql/item_sum.cc b/sql/item_sum.cc
> > index adf48f6..03600b7 100644
> > --- a/sql/item_sum.cc
> > +++ b/sql/item_sum.cc
> > @@ -1762,7 +1762,7 @@ double Item_sum_std::val_real()
> >   {
> >     DBUG_ASSERT(fixed == 1);
> >     double nr= Item_sum_variance::val_real();
> > -  DBUG_ASSERT(nr >= 0.0);
> > +  DBUG_ASSERT(nr >= 0.0 || my_isinf(nr));
> >     return sqrt(nr);
> >   }
>
> is it ok to do sqrt(inf)? what will it be? 0? inf? nan?
> may be this should return NULL in inf case?
>
> Regards,
> Sergei
> Chief Architect MariaDB
> and security@xxxxxxxxxxx
diff --git a/mysql-test/r/func_group.result b/mysql-test/r/func_group.result
index 0253548..38fae2f 100644
--- a/mysql-test/r/func_group.result
+++ b/mysql-test/r/func_group.result
@@ -2297,3 +2297,15 @@ FROM t1;
 C_1	C_2	C_3
 NULL	100	200
 DROP TABLE t1;
+#
+# MDEV-10468 Assertion `nr >= 0.0' failed in Item_sum_std::val_real()
+#
+SELECT STDDEV_POP(f) FROM (SELECT "1e+309" AS f UNION SELECT "-1e+309" AS f) tbl;
+STDDEV_POP(f)
+1.7976931348623157e308
+Warnings:
+Warning	1292	Truncated incorrect DOUBLE value: '1e+309'
+Warning	1292	Truncated incorrect DOUBLE value: '-1e+309'
+SELECT STDDEV(f) FROM (SELECT 1.7976931348623157e+308 AS f UNION SELECT -1.7976931348623157e+308 AS f) tbl;
+STDDEV(f)
+1.7976931348623157e308
diff --git a/mysql-test/t/func_group.test b/mysql-test/t/func_group.test
index 5824d99..7013009 100644
--- a/mysql-test/t/func_group.test
+++ b/mysql-test/t/func_group.test
@@ -1590,3 +1590,9 @@ SELECT
   SUM(data3) AS C_3
 FROM t1;
 DROP TABLE t1;
+
+--echo #
+--echo # MDEV-10468 Assertion `nr >= 0.0' failed in Item_sum_std::val_real()
+--echo #
+SELECT STDDEV_POP(f) FROM (SELECT "1e+309" AS f UNION SELECT "-1e+309" AS f) tbl;
+SELECT STDDEV(f) FROM (SELECT 1.7976931348623157e+308 AS f UNION SELECT -1.7976931348623157e+308 AS f) tbl;
diff --git a/sql/item_sum.cc b/sql/item_sum.cc
index 4458951..02d2875 100644
--- a/sql/item_sum.cc
+++ b/sql/item_sum.cc
@@ -1762,6 +1762,8 @@ double Item_sum_std::val_real()
 {
   DBUG_ASSERT(fixed == 1);
   double nr= Item_sum_variance::val_real();
+  if (my_isinf(nr))
+    return DBL_MAX;
   DBUG_ASSERT(nr >= 0.0);
   return sqrt(nr);
 }