Re: [Firebird-devel] Error 335544333 creating index on columns with collation

[Peter J. <pj...@wa...>]

Hi Thomas, All,

> That was for easier understanding, it also happens with 'real' texts,
> try eg: 'Gro=DF-Au=DFenhand.K' instead of the above
> =3D> same problem.

That's really bad. I'll have a look at (but without a shortterm
possibility to fix something).

> Just out of curiousity, does this only happen for the
> =DF-Umlaut or also for others (=E4,=F6,=FC)?

No the =F6=E4=FC umlauts aren't effected. The source of this problem,
is effectively replacing eszet ligature with "ss" for comparison
purposes, when de_de (and some others) collation is deployed.

So the length of the key grows. I thought (and hoped) that there
was some spare place to absorb some eszets in the string, but
which would be overrun by a string completely made of eszet ligatures.

> What I do not understand is, why there is no problem when inserting
> the data with the existing index but then after dropping and creating
> the index the problem appears.

From a shallow understanding of the code in question, I would diagnose
a classical buffer overrun. And that would mean undefined behaviour,
so in effect, everything may happen.

[...]
> But this only if the problem is related only for the =DF=3D>ss expansion=
. If
> this is also related to the =E4,=F6,=FC then a collation sequence doesn'=
t make
> sense IMO. Otherwise waiting for a better implementation would be better=
.

Are you setup to recomplile fbintl.dll from sources?

This patch would disable the problematic expansions in de_de:

--- bl88591de0.h        Sat Oct 11 11:25:15 2003
+++ patched\bl88591de0.h        Sat Nov 15 11:14:58 2003
@@ -17,7 +17,7 @@
  * Contributor(s): ______________________________________.
  */
 
-const int NUM_EXPAND_CHARS             =3D 5;
+const int NUM_EXPAND_CHARS      =3D 0;
 const int NUM_COMPRESS_CHARS   =3D 0;
 const int LOWERCASE_LEN                        =3D 256;
 const int UPPERCASE_LEN                        =3D 256;
@@ -554,11 +554,6 @@
 };
 
 static const ExpandChar ExpansionTbl[NUM_EXPAND_CHARS + 1] =3D {
-       {230, 97, 101},                         /* =E6 -> ae */
-       {198, 65, 69},                          /* =C6 -> AE */
-       {223, 115, 115},                        /* =DF -> ss */
-       {254, 116, 104},                        /* =FE -> th */
-       {222, 84, 72},                          /* =DE -> TH */
        {0, 0, 0}                                       /* END OF TABLE */
 };


Best Regards,
Peter Jacobi

BTW: I assume, you are not allowed to comment, whether
Dr=E4ger is planning to use Firebird in production code?