Index: src/insert.c
==================================================================
--- src/insert.c
+++ src/insert.c
@@ -1665,10 +1665,27 @@
   }
   
   *pbMayReplace = seenReplace;
   VdbeModuleComment((v, "END: GenCnstCks(%d)", seenReplace));
 }
+
+/*
+** Change the P5 operand on the last opcode (which should be an OP_MakeRecord)
+** to be the number of columns in table pTab that must not be NULL-trimmed.
+**
+** Or if no columns of pTab may be NULL-trimmed, leave P5 at zero.
+*/
+void sqlite3SetMakeRecordP5(Vdbe *v, Table *pTab){
+  u16 i;
+
+  /* Records with omitted columns are only allowed for schema format
+  ** version 2 and later (SQLite version 3.1.4, 2005-02-20). */
+  if( pTab->pSchema->file_format<2 ) return;
+
+  for(i=pTab->nCol; i>1 && pTab->aCol[i-1].pDflt==0; i--){}
+  sqlite3VdbeChangeP5(v, i);
+}
 
 /*
 ** This routine generates code to finish the INSERT or UPDATE operation
 ** that was started by a prior call to sqlite3GenerateConstraintChecks.
 ** A consecutive range of registers starting at regNewData contains the
@@ -1725,10 +1742,11 @@
   }
   if( !HasRowid(pTab) ) return;
   regData = regNewData + 1;
   regRec = sqlite3GetTempReg(pParse);
   sqlite3VdbeAddOp3(v, OP_MakeRecord, regData, pTab->nCol, regRec);
+  sqlite3SetMakeRecordP5(v, pTab);
   if( !bAffinityDone ){
     sqlite3TableAffinity(v, pTab, 0);
     sqlite3ExprCacheAffinityChange(pParse, regData, pTab->nCol);
   }
   if( pParse->nested ){

Index: src/sqliteInt.h
==================================================================
--- src/sqliteInt.h
+++ src/sqliteInt.h
@@ -3788,10 +3788,11 @@
 void sqlite3GenerateRowIndexDelete(Parse*, Table*, int, int, int*, int);
 int sqlite3GenerateIndexKey(Parse*, Index*, int, int, int, int*,Index*,int);
 void sqlite3ResolvePartIdxLabel(Parse*,int);
 void sqlite3GenerateConstraintChecks(Parse*,Table*,int*,int,int,int,int,
                                      u8,u8,int,int*,int*);
+void sqlite3SetMakeRecordP5(Vdbe*,Table*);
 void sqlite3CompleteInsertion(Parse*,Table*,int,int,int,int*,int,int,int);
 int sqlite3OpenTableAndIndices(Parse*, Table*, int, u8, int, u8*, int*, int*);
 void sqlite3BeginWriteOperation(Parse*, int, int);
 void sqlite3MultiWrite(Parse*);
 void sqlite3MayAbort(Parse*);

Index: src/vdbe.c
==================================================================
--- src/vdbe.c
+++ src/vdbe.c
@@ -2774,10 +2774,22 @@
     do{
       applyAffinity(pRec++, *(zAffinity++), encoding);
       assert( zAffinity[0]==0 || pRec<=pLast );
     }while( zAffinity[0] );
   }
+
+  /* NULLs can be safely trimmed from the end of the record, as long as
+  ** as the schema format is 2 or more and none of the omitted columns
+  ** have a non-NULL default value.  Also, the record must be left with
+  ** at least one field.  If P5>0 then it will be one more than the
+  ** index of the right-most column with a non-NULL default value */
+  if( pOp->p5 ){
+    while( (pLast->flags & MEM_Null)!=0 && nField>pOp->p5 ){
+      pLast--;
+      nField--;
+    }
+  }
 
   /* Loop through the elements that will make up the record to figure
   ** out how much space is required for the new record.
   */
   pRec = pLast;

Index: src/vdbe.h
==================================================================
--- src/vdbe.h
+++ src/vdbe.h
@@ -39,12 +39,11 @@
 ** as an instance of the following structure:
 */
 struct VdbeOp {
   u8 opcode;          /* What operation to perform */
   signed char p4type; /* One of the P4_xxx constants for p4 */
-  u8 notUsed1;
-  u8 p5;              /* Fifth parameter is an unsigned character */
+  u16 p5;             /* Fifth parameter is an unsigned 16-bit integer */
   int p1;             /* First operand */
   int p2;             /* Second parameter (often the jump destination) */
   int p3;             /* The third parameter */
   union p4union {     /* fourth parameter */
     int i;                 /* Integer value if p4type==P4_INT32 */
@@ -192,11 +191,11 @@
 void sqlite3VdbeAddParseSchemaOp(Vdbe*,int,char*);
 void sqlite3VdbeChangeOpcode(Vdbe*, u32 addr, u8);
 void sqlite3VdbeChangeP1(Vdbe*, u32 addr, int P1);
 void sqlite3VdbeChangeP2(Vdbe*, u32 addr, int P2);
 void sqlite3VdbeChangeP3(Vdbe*, u32 addr, int P3);
-void sqlite3VdbeChangeP5(Vdbe*, u8 P5);
+void sqlite3VdbeChangeP5(Vdbe*, u16 P5);
 void sqlite3VdbeJumpHere(Vdbe*, int addr);
 int sqlite3VdbeChangeToNoop(Vdbe*, int addr);
 int sqlite3VdbeDeletePriorOpcode(Vdbe*, u8 op);
 void sqlite3VdbeChangeP4(Vdbe*, int addr, const char *zP4, int N);
 void sqlite3VdbeAppendP4(Vdbe*, void *pP4, int p4type);

Index: src/vdbeapi.c
==================================================================
--- src/vdbeapi.c
+++ src/vdbeapi.c
@@ -1658,10 +1658,11 @@
 ** This function is called from within a pre-update callback to retrieve
 ** a field of the row currently being updated or deleted.
 */
 int sqlite3_preupdate_old(sqlite3 *db, int iIdx, sqlite3_value **ppValue){
   PreUpdate *p = db->pPreUpdate;
+  Mem *pMem;
   int rc = SQLITE_OK;
 
   /* Test that this call is being made from within an SQLITE_DELETE or
   ** SQLITE_UPDATE pre-update callback, and that iIdx is within range. */
   if( !p || p->op==SQLITE_INSERT ){
@@ -1691,21 +1692,18 @@
       goto preupdate_old_out;
     }
     p->aRecord = aRec;
   }
 
-  if( iIdx>=p->pUnpacked->nField ){
+  pMem = *ppValue = &p->pUnpacked->aMem[iIdx];
+  if( iIdx==p->pTab->iPKey ){
+    sqlite3VdbeMemSetInt64(pMem, p->iKey1);
+  }else if( iIdx>=p->pUnpacked->nField ){
     *ppValue = (sqlite3_value *)columnNullValue();
-  }else{
-    Mem *pMem = *ppValue = &p->pUnpacked->aMem[iIdx];
-    *ppValue = &p->pUnpacked->aMem[iIdx];
-    if( iIdx==p->pTab->iPKey ){
-      sqlite3VdbeMemSetInt64(pMem, p->iKey1);
-    }else if( p->pTab->aCol[iIdx].affinity==SQLITE_AFF_REAL ){
-      if( pMem->flags & MEM_Int ){
-        sqlite3VdbeMemRealify(pMem);
-      }
+  }else if( p->pTab->aCol[iIdx].affinity==SQLITE_AFF_REAL ){
+    if( pMem->flags & MEM_Int ){
+      sqlite3VdbeMemRealify(pMem);
     }
   }
 
  preupdate_old_out:
   sqlite3Error(db, rc);
@@ -1774,17 +1772,15 @@
         rc = SQLITE_NOMEM;
         goto preupdate_new_out;
       }
       p->pNewUnpacked = pUnpack;
     }
-    if( iIdx>=pUnpack->nField ){
+    pMem = &pUnpack->aMem[iIdx];
+    if( iIdx==p->pTab->iPKey ){
+      sqlite3VdbeMemSetInt64(pMem, p->iKey2);
+    }else if( iIdx>=pUnpack->nField ){
       pMem = (sqlite3_value *)columnNullValue();
-    }else{
-      pMem = &pUnpack->aMem[iIdx];
-      if( iIdx==p->pTab->iPKey ){
-        sqlite3VdbeMemSetInt64(pMem, p->iKey2);
-      }
     }
   }else{
     /* For an UPDATE, memory cell (p->iNewReg+1+iIdx) contains the required
     ** value. Make a copy of the cell contents and return a pointer to it.
     ** It is not safe to return a pointer to the memory cell itself as the

Index: src/vdbeaux.c
==================================================================
--- src/vdbeaux.c
+++ src/vdbeaux.c
@@ -781,11 +781,11 @@
   sqlite3VdbeGetOp(p,addr)->p2 = val;
 }
 void sqlite3VdbeChangeP3(Vdbe *p, u32 addr, int val){
   sqlite3VdbeGetOp(p,addr)->p3 = val;
 }
-void sqlite3VdbeChangeP5(Vdbe *p, u8 p5){
+void sqlite3VdbeChangeP5(Vdbe *p, u16 p5){
   assert( p->nOp>0 || p->db->mallocFailed );
   if( p->nOp>0 ) p->aOp[p->nOp-1].p5 = p5;
 }
 
 /*
@@ -4583,14 +4583,14 @@
 ** structure itself, using sqlite3DbFree().
 **
 ** This function is used to free UnpackedRecord structures allocated by
 ** the vdbeUnpackRecord() function found in vdbeapi.c.
 */
-static void vdbeFreeUnpacked(sqlite3 *db, UnpackedRecord *p){
+static void vdbeFreeUnpacked(sqlite3 *db, int nField, UnpackedRecord *p){
   if( p ){
     int i;
-    for(i=0; i<p->nField; i++){
+    for(i=0; i<nField; i++){
       Mem *pMem = &p->aMem[i];
       if( pMem->zMalloc ) sqlite3VdbeMemRelease(pMem);
     }
     sqlite3DbFree(db, p);
   }
@@ -4645,16 +4645,16 @@
 
   db->pPreUpdate = &preupdate;
   db->xPreUpdateCallback(db->pPreUpdateArg, db, op, zDb, zTbl, iKey1, iKey2);
   db->pPreUpdate = 0;
   sqlite3DbFree(db, preupdate.aRecord);
-  vdbeFreeUnpacked(db, preupdate.pUnpacked);
-  vdbeFreeUnpacked(db, preupdate.pNewUnpacked);
+  vdbeFreeUnpacked(db, preupdate.keyinfo.nField+1, preupdate.pUnpacked);
+  vdbeFreeUnpacked(db, preupdate.keyinfo.nField+1, preupdate.pNewUnpacked);
   if( preupdate.aNew ){
     int i;
     for(i=0; i<pCsr->nField; i++){
       sqlite3VdbeMemRelease(&preupdate.aNew[i]);
     }
     sqlite3DbFree(db, preupdate.aNew);
   }
 }
 #endif /* SQLITE_ENABLE_PREUPDATE_HOOK */

Index: test/exclusive2.test
==================================================================
--- test/exclusive2.test
+++ test/exclusive2.test
@@ -119,17 +119,17 @@
 #
 do_test exclusive2-1.1 {
   execsql {
     BEGIN;
     CREATE TABLE t1(a, b);
-    INSERT INTO t1(a) VALUES(randstr(10, 400));
-    INSERT INTO t1(a) VALUES(randstr(10, 400));
-    INSERT INTO t1(a) SELECT randstr(10, 400) FROM t1;
-    INSERT INTO t1(a) SELECT randstr(10, 400) FROM t1;
-    INSERT INTO t1(a) SELECT randstr(10, 400) FROM t1;
-    INSERT INTO t1(a) SELECT randstr(10, 400) FROM t1;
-    INSERT INTO t1(a) SELECT randstr(10, 400) FROM t1;
+    INSERT INTO t1(a, b) VALUES(randstr(10, 400), 0);
+    INSERT INTO t1(a, b) VALUES(randstr(10, 400), 0);
+    INSERT INTO t1(a, b) SELECT randstr(10, 400), 0 FROM t1;
+    INSERT INTO t1(a, b) SELECT randstr(10, 400), 0 FROM t1;
+    INSERT INTO t1(a, b) SELECT randstr(10, 400), 0 FROM t1;
+    INSERT INTO t1(a, b) SELECT randstr(10, 400), 0 FROM t1;
+    INSERT INTO t1(a, b) SELECT randstr(10, 400), 0 FROM t1;
     COMMIT;
     SELECT count(*) FROM t1;
   }
 } {64}
 do_test exclusive2-1.2.1 {
@@ -152,11 +152,11 @@
   sqlite3 db2 test.db
   t1sig db2
 } $::sig
 do_test exclusive2-1.5 {
   execsql {
-    UPDATE t1 SET b=a, a=NULL;
+    UPDATE t1 SET b=a, a=0;
   } db2
   expr {[t1sig db2] eq $::sig}
 } 0
 do_test exclusive2-1.6 {
   readPagerChangeCounter test.db

Index: test/hook.test
==================================================================
--- test/hook.test
+++ test/hook.test
@@ -851,7 +851,58 @@
 # No preupdate callbacks for modifying sqlite_master.
 do_preupdate_test 8.1 {
   CREATE TABLE x1(x, y);
 } {
 }
+
+#-------------------------------------------------------------------------
+reset_db
+db preupdate hook preupdate_hook
+do_execsql_test 9.0 {
+  CREATE TABLE t1(a INTEGER PRIMARY KEY, b, c);
+  CREATE TABLE t2(a, b INTEGER PRIMARY KEY);
+}
+do_preupdate_test 9.1 {
+  INSERT INTO t1 VALUES(456, NULL, NULL);
+} {
+  INSERT main t1 456 456  0  456 {} {}
+}
+do_execsql_test 9.2 {
+  ALTER TABLE t1 ADD COLUMN d;
+}
+do_preupdate_test 9.3 {
+  INSERT INTO t1(a, b, c) VALUES(457, NULL, NULL);
+} {
+  INSERT main t1 457 457  0  457 {} {} {}
+}
+do_preupdate_test 9.4 {
+  DELETE FROM t1 WHERE a=456
+} {
+  DELETE main t1 456 456  0  456 {} {} {}
+}
+do_preupdate_test 9.5 {
+  INSERT INTO t2 DEFAULT VALUES;
+} {
+  INSERT main t2 1 1  0  {} 1
+} 
+do_preupdate_test 9.6 {
+  INSERT INTO t1 DEFAULT VALUES;
+} {
+  INSERT main t1 458 458  0  458 {} {} {}
+} 
+
+
+do_execsql_test 10.0 {
+  CREATE TABLE t3(a, b INTEGER PRIMARY KEY);
+}
+do_preupdate_test 10.1 {
+  INSERT INTO t3 DEFAULT VALUES
+} {
+  INSERT main t3 1 1 0 {} 1
+}
+do_execsql_test 10.2 { SELECT * FROM t3 } {{} 1}
+do_preupdate_test 10.3 {
+  DELETE FROM t3 WHERE b=1
+} {DELETE main t3 1 1 0 {} 1}
+
 
 finish_test

Index: test/tester.tcl
==================================================================
--- test/tester.tcl
+++ test/tester.tcl
@@ -459,11 +459,11 @@
           sqlite3_memdebug_log start
         }
       }
       {^-+backtrace=.+$} {
         foreach {dummy cmdlinearg(backtrace)} [split $a =] break
-        sqlite3_memdebug_backtrace $value
+        sqlite3_memdebug_backtrace $cmdlinearg(backtrace)
       }
       {^-+binarylog=.+$} {
         foreach {dummy cmdlinearg(binarylog)} [split $a =] break
         set cmdlinearg(binarylog) [file normalize $cmdlinearg(binarylog)]
       }