bk commit into 5.1 tree (pekka:1.2549) BUG#34515

[pekka]

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ChangeSet@stripped, 2008-03-25 11:37:45+02:00, pekka@stripped +1 -0
  ndb - bug#34515 fix

  storage/ndb/src/kernel/blocks/dbtup/DbtupRoutines.cpp@stripped, 2008-03-25 11:36:44+02:00,
pekka@stripped +17 -0
    bug#34515 - on update of fixed attribute, zero unused bytes in last word.
    needed for DBTUX Decimal compare.  (variable attribute case ignored.)

diff -Nrup a/storage/ndb/src/kernel/blocks/dbtup/DbtupRoutines.cpp
b/storage/ndb/src/kernel/blocks/dbtup/DbtupRoutines.cpp
--- a/storage/ndb/src/kernel/blocks/dbtup/DbtupRoutines.cpp	2007-10-25 11:59:16 +03:00
+++ b/storage/ndb/src/kernel/blocks/dbtup/DbtupRoutines.cpp	2008-03-25 11:36:44 +02:00
@@ -988,6 +988,23 @@ Dbtup::updateFixedSizeTHManyWordNotNULL(
                        &inBuffer[indexBuf + 1],
                        noOfWords);
       
+      /*
+       * bug#34515 - zero unused bytes in last word
+       * 1) writer should zero them
+       * 2) do it here always to avoid randomness
+       * 3) reader should ignore unused bytes
+       * Restart code can fail 1) (not analyzed).
+       * DBTUX can fail 3) in Decimal comparisons.
+       * This will be fixed in DBTUX cleanup in 6.x.
+       */
+      Uint32 noOfBytes = AttributeDescriptor::getSizeInBytes(attrDescriptor);
+      Uint32 unused = (noOfWords << 2) - noOfBytes;
+      if (unused != 0) {
+        ndbassert(unused < 4);
+        char* base = (char*)&tuple_header[updateOffset];
+        memset(&base[noOfBytes], 0, unused);
+      }
+
       return true;
     } else {
       jam();