From e6d81ad3383fa5f6dc282ff7d85d3e2cdbec5a9c Mon Sep 17 00:00:00 2001
From: "gkodinov/kgeorge@magare.gmz[kgeorge]" <>
Date: Mon, 26 Mar 2007 13:17:40 +0300
Subject: [PATCH] Bug #27164: not reseting the data pointer  to 0 causes wrong
 (large) length to be read  from the row in _mi_calc_blob_length() when 
 storing NULL values in (e.g) POINT columns.  This large length is then used
 to allocate  a block of memory that (on some OSes) causes  trouble.  Fixed by
 calling the base class's  Field_blob::reset() from Field_geom::reset()  that
 is called when storing a NULL value into  the column.

---
 mysql-test/r/gis.result | 6 ++++++
 mysql-test/t/gis.test   | 8 ++++++++
 sql/field.h             | 2 +-
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/mysql-test/r/gis.result b/mysql-test/r/gis.result
index de7e44ed7b2..643a3d6b434 100644
--- a/mysql-test/r/gis.result
+++ b/mysql-test/r/gis.result
@@ -718,4 +718,10 @@ point(b, b) IS NULL	linestring(b) IS NULL	polygon(b) IS NULL	multipoint(b) IS NU
 1	1	1	1	1	1	1
 0	1	1	1	1	1	1
 drop table t1;
+CREATE TABLE t1(a POINT) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (NULL);
+SELECT * FROM t1;
+a
+NULL
+DROP TABLE t1;
 End of 4.1 tests
diff --git a/mysql-test/t/gis.test b/mysql-test/t/gis.test
index 6bd0db92152..7182e040d46 100644
--- a/mysql-test/t/gis.test
+++ b/mysql-test/t/gis.test
@@ -411,4 +411,12 @@ from t1;
 
 drop table t1;
 
+#
+# Bug #27164: Crash when mixing InnoDB and MyISAM Geospatial tables
+#
+CREATE TABLE t1(a POINT) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (NULL);
+SELECT * FROM t1;
+DROP TABLE t1;
+
 --echo End of 4.1 tests
diff --git a/sql/field.h b/sql/field.h
index d3e38db83d1..58177747120 100644
--- a/sql/field.h
+++ b/sql/field.h
@@ -1115,7 +1115,7 @@ public:
   int  store(const char *to, uint length, CHARSET_INFO *charset);
   int  store(double nr) { return 1; }
   int  store(longlong nr) { return 1; }
-  int  reset(void) { return !maybe_null(); }
+  int  reset(void) { return !maybe_null() || Field_blob::reset(); }
 
   void get_key_image(char *buff,uint length, CHARSET_INFO *cs,imagetype type);
   void set_key_image(char *buff,uint length, CHARSET_INFO *cs);