I found another bug in btree index. Looking at the code it seems that NULL
keys are never used to build or scan a btree index (see the explain commands
in the example). However this is not the case when a null key is retrieved
in an outer loop of a join select and used in an index scan of an inner loop.
This bug causes at least three kinds of problems:
1) the backend crashes when it tries to compare a text string with a null.
2) it is not possible to find tuples with null keys in a join.
3) null is considered equal to 0 when the datum is passed by value, see
the last query.
Submitted by: Massimo Dal Zotto <dz@cs.unitn.it>
- Added the header access/heapam.h.
- Changed all instances of "length" to "data_length" to quiet
the compiler.
- initialized a few variables. The compiler couldn't see that
the code guaranteed that these would be initialized before
being dereferenced. If anyone wants to check my work follow
the usage of these variables and make sure that this true
and wasn't actually a bug in the original code.
- added a missing break statement to a default case. This
was a benign error but bad style.
- layed out heap_sysattrlen differently. I think this way
makes the structure of the code crystal clear. There should
be no actual difference in the actual behaviour of the code.
Submitted by: darcy@druid.druid.com (D'Arcy J.M. Cain)
Here's a small patch that my run-time checker whines about
incessantly. The justification for the patch is along the
lines of passing a NULL is allowed if you have an
arguement that is a *POINTER* to something, but if
the arguement is an array reference, it's not really
a "pointer", so it can't be NULL.
If you question this, I refer you to
<URL:http://www.va.pubnix.com/staff/djm/lore/arrays-are-not-pointers>
Anyways, here's the patch:
-Kurt
Submitted by: "Kurt J. Lidl" <lidl@va.pubnix.com>
