diff --git a/manifest b/manifest
index f2dbc032db..a17919ee09 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Improved\scomments\son\sthe\sconstraint\schecking\slogic.
-D 2013-10-29T16:14:35.997
+C Import\sthe\sautomatic\scomment\sgenerating\schanges\sfrom\strunk.
+D 2013-10-29T20:47:26.079
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 0522b53cdc1fcfc18f3a98e0246add129136c654
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -145,8 +145,8 @@ F main.mk c6a433cb334bbb019625c137ab5d5e7568b47cff
 F mkdll.sh 7d09b23c05d56532e9d44a50868eb4b12ff4f74a
 F mkextu.sh 416f9b7089d80e5590a29692c9d9280a10dbad9f
 F mkextw.sh d2a981497b404d6498f5ff3e3b1f3816bdfcb338
-F mkopcodec.awk f6fccee29e68493bfd90a2e0466ede5fa94dd2fc
-F mkopcodeh.awk e7334b45c023b5ee2efc6e8f479560c2026fa34a
+F mkopcodec.awk 393b20a2a99557ca695f7e1261c32d087ff7c0b4
+F mkopcodeh.awk 987ee588ff3bb4043bed2185c1ee2bdc39b1e526
 F mkso.sh fd21c06b063bb16a5d25deea1752c2da6ac3ed83
 F mptest/config01.test 3c6adcbc50b991866855f1977ff172eb6d901271
 F mptest/config02.test 4415dfe36c48785f751e16e32c20b077c28ae504
@@ -279,11 +279,11 @@ F src/update.c e39378bc5ed0c42e80624229703e59b5c7a4d50a
 F src/utf.c 6fc6c88d50448c469c5c196acf21617a24f90269
 F src/util.c 2fa6c821d28bbdbeec1b2a7b091a281c9ef8f918
 F src/vacuum.c 3728d74919d4fb1356f9e9a13e27773db60b7179
-F src/vdbe.c 7d23d61c84cb1116e36a70b050f2a4ae1a2aaae3
+F src/vdbe.c cb3df2d7b2ebadf22a39efcfb12a1277e273616e
 F src/vdbe.h 4f554b5627f26710c4c36d919110a3fc611ca5c4
 F src/vdbeInt.h 42dcff74dbeb2b071e569b53f885fc9c2e4b4cb0
 F src/vdbeapi.c 93a22a9ba2abe292d5c2cf304d7eb2e894dde0ed
-F src/vdbeaux.c 4ccdfd27f97fec98385f53fc8c880f1873137d95
+F src/vdbeaux.c 3c36d92d3ad7225e0436474f4256243e5ceaeabb
 F src/vdbeblob.c ef973d8d9f8170015343dd8824f795da675caa87
 F src/vdbemem.c 6087553f2c61c06c8e1ab3959a60e174d6240c98
 F src/vdbesort.c 3937e06b2a0e354500e17dc206ef4c35770a5017
@@ -1127,7 +1127,7 @@ F tool/vdbe-compress.tcl f12c884766bd14277f4fcedcae07078011717381
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh d1a6de74685f360ab718efda6265994b99bbea01
 F tool/win/sqlite.vsix 030f3eeaf2cb811a3692ab9c14d021a75ce41fff
-P 9f8191d1d833acaaf612fdff8cc6bd544c042986
-R 1ffaeb4130b0ebfe6aa0338f8dfd6db1
+P 141a38a7a636e3e4255b59c27df4a1b3d6f26e97 5f310c6a22b8bb5f860296074aee130c14101681
+R 092c8ad63995bcb3387c2f88e6abbbb4
 U drh
-Z 4dc4c03fad5693ab5ce15641b23c251b
+Z 2daff0292132d8122decef0d377e8179
diff --git a/manifest.uuid b/manifest.uuid
index e55b1428f5..bc00d07846 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-141a38a7a636e3e4255b59c27df4a1b3d6f26e97
\ No newline at end of file
+8bb51da1305d5e35c7b75bbb176c21e04ea2a48a
\ No newline at end of file
diff --git a/mkopcodec.awk b/mkopcodec.awk
index 2ef77d4cca..f4a09bf3e5 100644
--- a/mkopcodec.awk
+++ b/mkopcodec.awk
@@ -12,22 +12,36 @@ BEGIN {
   print "/* Automatically generated.  Do not edit */"
   print "/* See the mkopcodec.awk script for details. */"
   printf "#if !defined(SQLITE_OMIT_EXPLAIN)"
-  printf    " || !defined(NDEBUG)"
   printf    " || defined(VDBE_PROFILE)"
   print     " || defined(SQLITE_DEBUG)"
+  print "#if defined(SQLITE_DEBUG)"
+  print "# define OpHelp(X) \"\\0\" X"
+  print "#else"
+  print "# define OpHelp(X)"
+  print "#endif"
   print "const char *sqlite3OpcodeName(int i){"
   print " static const char *const azName[] = { \"?\","
   mx = 0
 }
-/define OP_/ {
+/^.define OP_/ {
   sub("OP_","",$2)
   i = $3+0
   label[i] = $2
   if( mx<i ) mx = i
+  for(j=5; j<NF; j++) if( $j=="synopsis:" ) break
+  if( j<NF ){
+    j++
+    x = $j
+    for(j=j+1; j<NF; j++) x = x " " $j
+    synopsis[i] = x
+  }else{
+    synopsis[i] = ""
+  }
 }
 END {
   for(i=1; i<=mx; i++){
-    printf "     /* %3d */ \"%s\",\n", i, label[i]
+    printf "     /* %3d */ %-18s OpHelp(\"%s\"),\n", i, \
+        "\"" label[i] "\"", synopsis[i]
   }
   print "  };"
   print "  return azName[i];"
diff --git a/mkopcodeh.awk b/mkopcodeh.awk
index 9685c3a0e8..f8da18e306 100644
--- a/mkopcodeh.awk
+++ b/mkopcodeh.awk
@@ -38,6 +38,33 @@
   tk[$2] = 0+$3    # tk[x] holds the numeric value for TK symbol X
 }
 
+# Find "/* Opcode: " lines in the vdbe.c file.  Each one introduces
+# a new opcode.  Remember which parameters are used.
+/^.. Opcode: / {
+  currentOp = "OP_" $3
+  m = 0
+  for(i=4; i<=NF; i++){
+    x = $i
+    if( x=="P1" ) m += 1
+    if( x=="P2" ) m += 2
+    if( x=="P3" ) m += 4
+    if( x=="P4" ) m += 8
+    if( x=="P5" ) m += 16
+  }
+  paramused[currentOp] = m
+}
+
+# Find "** Synopsis: " lines that follow Opcode:
+/^.. Synopsis: / {
+  if( currentOp ){
+    x = $3
+    for(i=4; i<=NF; i++){
+      x = x " " $i
+    }
+    synopsis[currentOp] = x
+  }
+}
+
 # Scan for "case OP_aaaa:" lines in the vdbe.c file
 /^case OP_/ {
   name = $2
@@ -136,10 +163,22 @@ END {
     if( !used[i] ){
       def[i] = "OP_NotUsed_" i 
     }
-    printf "#define %-25s %15d", def[i], i
+    printf "#define %-16s %3d", def[i], i
+    com = ""
     if( sameas[i] ){
-      printf "   /* same as %-12s*/", sameas[i]
-    } 
+      com = "same as " sameas[i]
+    }
+    x = synopsis[def[i]]
+    if( x ){
+      if( com=="" ){
+        com = "synopsis: " x
+      } else {
+        com = com ", synopsis: " x
+      }
+    }
+    if( com!="" ){
+      printf " /* %-42s */", com
+    }
     printf "\n"
   }
 
@@ -180,4 +219,15 @@ END {
     if( i%8==7 ) printf("\\\n");
   }
   print "}"
+  if( 0 ){
+    print "\n/* Bitmask to indicate which fields (P1..P5) of each opcode are"
+    print "** actually used.\n*/"
+    print "#define OP_PARAM_USED_INITIALIZER {\\"
+    for(i=0; i<=max; i++){
+      if( i%8==0 ) printf("/* %3d */",i)
+      printf " 0x%02x,", paramused[def[i]]
+      if( i%8==7 ) printf("\\\n");
+    }
+    print "}"
+  }
 }
diff --git a/src/vdbe.c b/src/vdbe.c
index 67a9a7bf58..f0400a64dc 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -805,6 +805,7 @@ case OP_Yield: {            /* in1 */
 }
 
 /* Opcode:  HaltIfNull  P1 P2 P3 P4 *
+** Synopsis:  if r[P3] null then halt
 **
 ** Check the value in register P3.  If it is NULL then Halt using
 ** parameter P1, P2, and P4 as if this were a Halt instruction.  If the
@@ -882,6 +883,7 @@ case OP_Halt: {
 }
 
 /* Opcode: Integer P1 P2 * * *
+** Synopsis: r[P2]=P1
 **
 ** The 32-bit integer value P1 is written into register P2.
 */
@@ -891,6 +893,7 @@ case OP_Integer: {         /* out2-prerelease */
 }
 
 /* Opcode: Int64 * P2 * P4 *
+** Synopsis: r[P2]=P4
 **
 ** P4 is a pointer to a 64-bit integer value.
 ** Write that value into register P2.
@@ -903,6 +906,7 @@ case OP_Int64: {           /* out2-prerelease */
 
 #ifndef SQLITE_OMIT_FLOATING_POINT
 /* Opcode: Real * P2 * P4 *
+** Synopsis: r[P2]=P4
 **
 ** P4 is a pointer to a 64-bit floating point value.
 ** Write that value into register P2.
@@ -916,6 +920,7 @@ case OP_Real: {            /* same as TK_FLOAT, out2-prerelease */
 #endif
 
 /* Opcode: String8 * P2 * P4 *
+** Synopsis: r[P2]='P4'
 **
 ** P4 points to a nul terminated UTF-8 string. This opcode is transformed 
 ** into an OP_String before it is executed for the first time.
@@ -950,6 +955,7 @@ case OP_String8: {         /* same as TK_STRING, out2-prerelease */
 }
   
 /* Opcode: String P1 P2 * P4 *
+** Synopsis: r[P2]='P4' (len=P1)
 **
 ** The string value P4 of length P1 (bytes) is stored in register P2.
 */
@@ -964,6 +970,7 @@ case OP_String: {          /* out2-prerelease */
 }
 
 /* Opcode: Null P1 P2 P3 * *
+** Synopsis:  r[P2..P3]=NULL
 **
 ** Write a NULL into registers P2.  If P3 greater than P2, then also write
 ** NULL into register P3 and every register in between P2 and P3.  If P3
@@ -992,6 +999,7 @@ case OP_Null: {           /* out2-prerelease */
 
 
 /* Opcode: Blob P1 P2 * P4
+** Synopsis: r[P2]=P4 (len=P1)
 **
 ** P4 points to a blob of data P1 bytes long.  Store this
 ** blob in register P2.
@@ -1005,6 +1013,7 @@ case OP_Blob: {                /* out2-prerelease */
 }
 
 /* Opcode: Variable P1 P2 * P4 *
+** Synopsis: r[P2]=parameter(P1,P4)
 **
 ** Transfer the values of bound parameter P1 into register P2
 **
@@ -1026,6 +1035,7 @@ case OP_Variable: {            /* out2-prerelease */
 }
 
 /* Opcode: Move P1 P2 P3 * *
+** Synopsis:  r[P2]=r[P1] N=P3
 **
 ** Move the values in register P1..P1+P3 over into
 ** registers P2..P2+P3.  Registers P1..P1+P3 are
@@ -1068,6 +1078,7 @@ case OP_Move: {
 }
 
 /* Opcode: Copy P1 P2 P3 * *
+** Synopsis: r[P2]=r[P1] N=P3
 **
 ** Make a copy of registers P1..P1+P3 into registers P2..P2+P3.
 **
@@ -1096,6 +1107,7 @@ case OP_Copy: {
 }
 
 /* Opcode: SCopy P1 P2 * * *
+** Synopsis: r[P2]=r[P1]
 **
 ** Make a shallow copy of register P1 into register P2.
 **
@@ -1120,6 +1132,7 @@ case OP_SCopy: {            /* in1, out2 */
 }
 
 /* Opcode: ResultRow P1 P2 * * *
+** Synopsis:  output=r[P1].. columns=P1
 **
 ** The registers P1 through P1+P2-1 contain a single row of
 ** results. This opcode causes the sqlite3_step() call to terminate
@@ -1191,6 +1204,7 @@ case OP_ResultRow: {
 }
 
 /* Opcode: Concat P1 P2 P3 * *
+** Synopsis: r[P3]=r[P2]+r[P3]
 **
 ** Add the text in register P1 onto the end of the text in
 ** register P2 and store the result in register P3.
@@ -1228,7 +1242,7 @@ case OP_Concat: {           /* same as TK_CONCAT, in1, in2, out3 */
     memcpy(pOut->z, pIn2->z, pIn2->n);
   }
   memcpy(&pOut->z[pIn2->n], pIn1->z, pIn1->n);
-  pOut->z[nByte] = 0;
+  pOut->z[nByte]=0;
   pOut->z[nByte+1] = 0;
   pOut->flags |= MEM_Term;
   pOut->n = (int)nByte;
@@ -1238,12 +1252,14 @@ case OP_Concat: {           /* same as TK_CONCAT, in1, in2, out3 */
 }
 
 /* Opcode: Add P1 P2 P3 * *
+** Synopsis:  r[P3]=r[P1]+r[P2]
 **
 ** Add the value in register P1 to the value in register P2
 ** and store the result in register P3.
 ** If either input is NULL, the result is NULL.
 */
 /* Opcode: Multiply P1 P2 P3 * *
+** Synopsis:  r[P3]=r[P1]*r[P2]
 **
 **
 ** Multiply the value in register P1 by the value in register P2
@@ -1251,12 +1267,14 @@ case OP_Concat: {           /* same as TK_CONCAT, in1, in2, out3 */
 ** If either input is NULL, the result is NULL.
 */
 /* Opcode: Subtract P1 P2 P3 * *
+** Synopsis:  r[P3]=r[P2]-r[P1]
 **
 ** Subtract the value in register P1 from the value in register P2
 ** and store the result in register P3.
 ** If either input is NULL, the result is NULL.
 */
 /* Opcode: Divide P1 P2 P3 * *
+** Synopsis:  r[P3]=r[P1]/r[P2]
 **
 ** Divide the value in register P1 by the value in register P2
 ** and store the result in register P3 (P3=P2/P1). If the value in 
@@ -1264,6 +1282,7 @@ case OP_Concat: {           /* same as TK_CONCAT, in1, in2, out3 */
 ** NULL, the result is NULL.
 */
 /* Opcode: Remainder P1 P2 P3 * *
+** Synopsis:  r[P3]=r[P1]%r[P2]
 **
 ** Compute the remainder after integer division of the value in
 ** register P1 by the value in register P2 and store the result in P3. 
@@ -1381,6 +1400,7 @@ case OP_CollSeq: {
 }
 
 /* Opcode: Function P1 P2 P3 P4 P5
+** Synopsis: r[P3]=func(r[P2]..) N=P5
 **
 ** Invoke a user function (P4 is a pointer to a Function structure that
 ** defines the function) with P5 arguments taken from register P2 and
@@ -1488,18 +1508,21 @@ case OP_Function: {
 }
 
 /* Opcode: BitAnd P1 P2 P3 * *
+** Synopsis:  r[P3]=r[P1]&r[P2]
 **
 ** Take the bit-wise AND of the values in register P1 and P2 and
 ** store the result in register P3.
 ** If either input is NULL, the result is NULL.
 */
 /* Opcode: BitOr P1 P2 P3 * *
+** Synopsis:  r[P3]=r[P1]|r[P2]
 **
 ** Take the bit-wise OR of the values in register P1 and P2 and
 ** store the result in register P3.
 ** If either input is NULL, the result is NULL.
 */
 /* Opcode: ShiftLeft P1 P2 P3 * *
+** Synopsis:  r[P3]=r[P2]<<r[P1]
 **
 ** Shift the integer value in register P2 to the left by the
 ** number of bits specified by the integer in register P1.
@@ -1507,6 +1530,7 @@ case OP_Function: {
 ** If either input is NULL, the result is NULL.
 */
 /* Opcode: ShiftRight P1 P2 P3 * *
+** Synopsis:  r[P3]=r[P2]>>r[P1]
 **
 ** Shift the integer value in register P2 to the right by the
 ** number of bits specified by the integer in register P1.
@@ -1566,6 +1590,7 @@ case OP_ShiftRight: {           /* same as TK_RSHIFT, in1, in2, out3 */
 }
 
 /* Opcode: AddImm  P1 P2 * * *
+** Synopsis:  r[P1]=r[P1]+P2
 ** 
 ** Add the constant P2 to the value in register P1.
 ** The result is always an integer.
@@ -1724,6 +1749,7 @@ case OP_ToReal: {                  /* same as TK_TO_REAL, in1 */
 #endif /* !defined(SQLITE_OMIT_CAST) && !defined(SQLITE_OMIT_FLOATING_POINT) */
 
 /* Opcode: Lt P1 P2 P3 P4 P5
+** Synopsis: r[P1] < r[P3]
 **
 ** Compare the values in register P1 and P3.  If reg(P3)<reg(P1) then
 ** jump to address P2.  
@@ -1758,6 +1784,7 @@ case OP_ToReal: {                  /* same as TK_TO_REAL, in1 */
 ** bit set.
 */
 /* Opcode: Ne P1 P2 P3 P4 P5
+** Synopsis: r[P1] != r[P3]
 **
 ** This works just like the Lt opcode except that the jump is taken if
 ** the operands in registers P1 and P3 are not equal.  See the Lt opcode for
@@ -1770,6 +1797,7 @@ case OP_ToReal: {                  /* same as TK_TO_REAL, in1 */
 ** the SQLITE_NULLEQ flag were omitted from P5.
 */
 /* Opcode: Eq P1 P2 P3 P4 P5
+** Synopsis: r[P1] == r[P3]
 **
 ** This works just like the Lt opcode except that the jump is taken if
 ** the operands in registers P1 and P3 are equal.
@@ -1782,18 +1810,21 @@ case OP_ToReal: {                  /* same as TK_TO_REAL, in1 */
 ** the SQLITE_NULLEQ flag were omitted from P5.
 */
 /* Opcode: Le P1 P2 P3 P4 P5
+** Synopsis: r[P1] <= r[P3]
 **
 ** This works just like the Lt opcode except that the jump is taken if
 ** the content of register P3 is less than or equal to the content of
 ** register P1.  See the Lt opcode for additional information.
 */
 /* Opcode: Gt P1 P2 P3 P4 P5
+** Synopsis: r[P1] > r[P3]
 **
 ** This works just like the Lt opcode except that the jump is taken if
 ** the content of register P3 is greater than the content of
 ** register P1.  See the Lt opcode for additional information.
 */
 /* Opcode: Ge P1 P2 P3 P4 P5
+** Synopsis: r[P1] >= r[P3]
 **
 ** This works just like the Lt opcode except that the jump is taken if
 ** the content of register P3 is greater than or equal to the content of
@@ -1984,6 +2015,7 @@ case OP_Jump: {             /* jump */
 }
 
 /* Opcode: And P1 P2 P3 * *
+** Synopsis: r[P3]=(r[P1] && r[P2])
 **
 ** Take the logical AND of the values in registers P1 and P2 and
 ** write the result into register P3.
@@ -1993,6 +2025,7 @@ case OP_Jump: {             /* jump */
 ** a NULL output.
 */
 /* Opcode: Or P1 P2 P3 * *
+** Synopsis: r[P3]=(r[P1] || r[P2])
 **
 ** Take the logical OR of the values in register P1 and P2 and
 ** store the answer in register P3.
@@ -2036,6 +2069,7 @@ case OP_Or: {             /* same as TK_OR, in1, in2, out3 */
 }
 
 /* Opcode: Not P1 P2 * * *
+** Synopsis: r[P2]= !r[P1]
 **
 ** Interpret the value in register P1 as a boolean value.  Store the
 ** boolean complement in register P2.  If the value in register P1 is 
@@ -2053,6 +2087,7 @@ case OP_Not: {                /* same as TK_NOT, in1, out2 */
 }
 
 /* Opcode: BitNot P1 P2 * * *
+** Synopsis: r[P1]= ~r[P1]
 **
 ** Interpret the content of register P1 as an integer.  Store the
 ** ones-complement of the P1 value into register P2.  If P1 holds
@@ -2141,6 +2176,7 @@ case OP_NotNull: {            /* same as TK_NOTNULL, jump, in1 */
 }
 
 /* Opcode: Column P1 P2 P3 P4 P5
+** Synopsis:  r[P3]=PX
 **
 ** Interpret the data that cursor P1 points to as a structure built using
 ** the MakeRecord instruction.  (See the MakeRecord opcode for additional
@@ -2477,6 +2513,7 @@ op_column_out:
 }
 
 /* Opcode: Affinity P1 P2 * P4 *
+** Synopsis: affinity(r[P1]) N=P2
 **
 ** Apply affinities to a range of P2 registers starting with P1.
 **
@@ -2503,6 +2540,7 @@ case OP_Affinity: {
 }
 
 /* Opcode: MakeRecord P1 P2 P3 P4 *
+** Synopsis: r[P3]=rec(r[P1]..) N=P2
 **
 ** Convert P2 registers beginning with P1 into the [record format]
 ** use as a data record in a database table or as a key
@@ -2635,6 +2673,7 @@ case OP_MakeRecord: {
 }
 
 /* Opcode: Count P1 P2 * * *
+** Synopsis: r[P2]=count()
 **
 ** Store the number of entries (an integer value) in the table or index 
 ** opened by cursor P1 in register P2
@@ -3111,6 +3150,7 @@ case OP_VerifyCookie: {
 }
 
 /* Opcode: OpenRead P1 P2 P3 P4 P5
+** Synopsis: root=P2 iDb=P3
 **
 ** Open a read-only cursor for the database table whose root page is
 ** P2 in a database file.  The database file is determined by P3. 
@@ -3141,6 +3181,7 @@ case OP_VerifyCookie: {
 ** See also OpenWrite.
 */
 /* Opcode: OpenWrite P1 P2 P3 P4 P5
+** Synopsis: root=P2 iDb=P3
 **
 ** Open a read/write cursor named P1 on the table or index whose root
 ** page is P2.  Or if P5!=0 use the content of register P2 to find the
@@ -3246,6 +3287,7 @@ case OP_OpenWrite: {
 }
 
 /* Opcode: OpenEphemeral P1 P2 * P4 P5
+** Synopsis: nColumn=P2
 **
 ** Open a new cursor P1 to a transient table.
 ** The cursor is always opened read/write even if 
@@ -3263,6 +3305,7 @@ case OP_OpenWrite: {
 ** added automatically.
 */
 /* Opcode: OpenAutoindex P1 P2 * P4 *
+** Synopsis: nColumn=P2
 **
 ** This opcode works the same as OP_OpenEphemeral.  It has a
 ** different name to distinguish its use.  Tables created using
@@ -3317,6 +3360,7 @@ case OP_OpenEphemeral: {
 }
 
 /* Opcode: SorterOpen P1 P2 * P4 *
+** Synopsis: nColumn=P2
 **
 ** This opcode works like OP_OpenEphemeral except that it opens
 ** a transient index that is specifically designed to sort large
@@ -3335,6 +3379,7 @@ case OP_SorterOpen: {
 }
 
 /* Opcode: OpenPseudo P1 P2 P3 * P5
+** Synopsis: content in r[P2].. N=P3
 **
 ** Open a new cursor that points to a fake table that contains a single
 ** row of data.  The content of that one row in the content of memory
@@ -3377,6 +3422,7 @@ case OP_Close: {
 }
 
 /* Opcode: SeekGe P1 P2 P3 P4 *
+** Synopsis: key=r[P3].. N=P4
 **
 ** If cursor P1 refers to an SQL table (B-Tree that uses integer keys), 
 ** use the value in register P3 as the key.  If cursor P1 refers 
@@ -3390,6 +3436,7 @@ case OP_Close: {
 ** See also: Found, NotFound, Distinct, SeekLt, SeekGt, SeekLe
 */
 /* Opcode: SeekGt P1 P2 P3 P4 *
+** Synopsis: key=r[P3].. N=P4
 **
 ** If cursor P1 refers to an SQL table (B-Tree that uses integer keys), 
 ** use the value in register P3 as a key. If cursor P1 refers 
@@ -3403,6 +3450,7 @@ case OP_Close: {
 ** See also: Found, NotFound, Distinct, SeekLt, SeekGe, SeekLe
 */
 /* Opcode: SeekLt P1 P2 P3 P4 * 
+** Synopsis: key=r[P3].. N=P4
 **
 ** If cursor P1 refers to an SQL table (B-Tree that uses integer keys), 
 ** use the value in register P3 as a key. If cursor P1 refers 
@@ -3416,6 +3464,7 @@ case OP_Close: {
 ** See also: Found, NotFound, Distinct, SeekGt, SeekGe, SeekLe
 */
 /* Opcode: SeekLe P1 P2 P3 P4 *
+** Synopsis: key=r[P3].. N=P4
 **
 ** If cursor P1 refers to an SQL table (B-Tree that uses integer keys), 
 ** use the value in register P3 as a key. If cursor P1 refers 
@@ -3581,6 +3630,7 @@ case OP_SeekGt: {       /* jump, in3 */
 }
 
 /* Opcode: Seek P1 P2 * * *
+** Synopsis:  intkey=r[P2]
 **
 ** P1 is an open table cursor and P2 is a rowid integer.  Arrange
 ** for P1 to move so that it points to the rowid given by P2.
@@ -3608,6 +3658,7 @@ case OP_Seek: {    /* in2 */
   
 
 /* Opcode: Found P1 P2 P3 P4 *
+** Synopsis: key=r[P3].. N=P4
 **
 ** If P4==0 then register P3 holds a blob constructed by MakeRecord.  If
 ** P4>0 then register P3 is the first of P4 registers that form an unpacked
@@ -3620,6 +3671,7 @@ case OP_Seek: {    /* in2 */
 ** See also: NotFound, NoConflict, NotExists. SeekGe
 */
 /* Opcode: NotFound P1 P2 P3 P4 *
+** Synopsis: key=r[P3] N=P4
 **
 ** If P4==0 then register P3 holds a blob constructed by MakeRecord.  If
 ** P4>0 then register P3 is the first of P4 registers that form an unpacked
@@ -3727,6 +3779,7 @@ case OP_Found: {        /* jump, in3 */
 }
 
 /* Opcode: NotExists P1 P2 P3 * *
+** Synopsis: intkey=r[P3]
 **
 ** P1 is the index of a cursor open on an SQL table btree (with integer
 ** keys).  P3 is an integer rowid.  If P1 does not contain a record with
@@ -3779,6 +3832,7 @@ case OP_NotExists: {        /* jump, in3 */
 }
 
 /* Opcode: Sequence P1 P2 * * *
+** Synopsis: r[P2]=rowid
 **
 ** Find the next available sequence number for cursor P1.
 ** Write the sequence number into register P2.
@@ -3794,6 +3848,7 @@ case OP_Sequence: {           /* out2-prerelease */
 
 
 /* Opcode: NewRowid P1 P2 P3 * *
+** Synopsis: r[P2]=rowid
 **
 ** Get a new integer record number (a.k.a "rowid") used as the key to a table.
 ** The record number is not previously used as a key in the database
@@ -3943,6 +3998,7 @@ case OP_NewRowid: {           /* out2-prerelease */
 }
 
 /* Opcode: Insert P1 P2 P3 P4 P5
+** Synopsis: intkey=r[P3] data=r[P2]
 **
 ** Write an entry into the table of cursor P1.  A new entry is
 ** created if it doesn't already exist or the data for an existing
@@ -3982,6 +4038,7 @@ case OP_NewRowid: {           /* out2-prerelease */
 ** for indices is OP_IdxInsert.
 */
 /* Opcode: InsertInt P1 P2 P3 P4 P5
+** Synopsis:  intkey=P3 data=r[P2]
 **
 ** This works exactly like OP_Insert except that the key is the
 ** integer value P3, not the value of the integer stored in register P3.
@@ -4132,6 +4189,7 @@ case OP_ResetCount: {
 }
 
 /* Opcode: SorterCompare P1 P2 P3
+** Synopsis:  if key(P1)!=r[P3] goto P2
 **
 ** P1 is a sorter cursor. This instruction compares the record blob in 
 ** register P3 with the entry that the sorter cursor currently points to.
@@ -4153,6 +4211,7 @@ case OP_SorterCompare: {
 };
 
 /* Opcode: SorterData P1 P2 * * *
+** Synopsis: r[P2]=data
 **
 ** Write into register P2 the current sorter data for sorter cursor P1.
 */
@@ -4167,6 +4226,7 @@ case OP_SorterData: {
 }
 
 /* Opcode: RowData P1 P2 * * *
+** Synopsis: r[P2]=data
 **
 ** Write into register P2 the complete row data for cursor P1.
 ** There is no interpretation of the data.  
@@ -4177,6 +4237,7 @@ case OP_SorterData: {
 ** of a real table, not a pseudo-table.
 */
 /* Opcode: RowKey P1 P2 * * *
+** Synopsis: r[P2]=key
 **
 ** Write into register P2 the complete row key for cursor P1.
 ** There is no interpretation of the data.  
@@ -4249,6 +4310,7 @@ case OP_RowData: {
 }
 
 /* Opcode: Rowid P1 P2 * * *
+** Synopsis: r[P2]=rowid
 **
 ** Store in register P2 an integer which is the key of the table entry that
 ** P1 is currently point to.
@@ -4406,7 +4468,7 @@ case OP_Rewind: {        /* jump */
   break;
 }
 
-/* Opcode: Next P1 P2 * P4 P5
+/* Opcode: Next P1 P2 * * P5
 **
 ** Advance cursor P1 so that it points to the next key/data pair in its
 ** table or index.  If there are no more key/value pairs then fall through
@@ -4476,6 +4538,7 @@ case OP_Next: {        /* jump */
 }
 
 /* Opcode: IdxInsert P1 P2 P3 * P5
+** Synopsis: key=r[P2]
 **
 ** Register P2 holds an SQL index key made using the
 ** MakeRecord instructions.  This opcode writes that key
@@ -4522,6 +4585,7 @@ case OP_IdxInsert: {        /* in2 */
 }
 
 /* Opcode: IdxDelete P1 P2 P3 * *
+** Synopsis: key=r[P2]..
 **
 ** The content of P3 registers starting at register P2 form
 ** an unpacked index key. This opcode removes that entry from the 
@@ -4558,6 +4622,7 @@ case OP_IdxDelete: {
 }
 
 /* Opcode: IdxRowid P1 P2 * * *
+** Synopsis: r[P2]=rowid
 **
 ** Write into register P2 an integer which is the last entry in the record at
 ** the end of the index key pointed to by cursor P1.  This integer should be
@@ -4593,6 +4658,7 @@ case OP_IdxRowid: {              /* out2-prerelease */
 }
 
 /* Opcode: IdxGE P1 P2 P3 P4 P5
+** Synopsis: key=r[P3] N=P4
 **
 ** The P4 register values beginning with P3 form an unpacked index 
 ** key that omits the ROWID.  Compare this key value against the index 
@@ -4607,6 +4673,7 @@ case OP_IdxRowid: {              /* out2-prerelease */
 ** the result is false whereas it would be true with IdxGT.
 */
 /* Opcode: IdxLT P1 P2 P3 P4 P5
+** Synopsis: key=r[P3] N=P4
 **
 ** The P4 register values beginning with P3 form an unpacked index 
 ** key that omits the ROWID.  Compare this key value against the index 
@@ -4759,6 +4826,7 @@ case OP_Clear: {
 }
 
 /* Opcode: CreateTable P1 P2 * * *
+** Synopsis: r[P2]=root iDb=P1
 **
 ** Allocate a new table in the main database file if P1==0 or in the
 ** auxiliary database file if P1==1 or in an attached database if
@@ -4772,6 +4840,7 @@ case OP_Clear: {
 ** See also: CreateIndex
 */
 /* Opcode: CreateIndex P1 P2 * * *
+** Synopsis: r[P2]=root iDb=P1
 **
 ** Allocate a new index in the main database file if P1==0 or in the
 ** auxiliary database file if P1==1 or in an attached database if
@@ -4973,6 +5042,7 @@ case OP_IntegrityCk: {
 #endif /* SQLITE_OMIT_INTEGRITY_CHECK */
 
 /* Opcode: RowSetAdd P1 P2 * * *
+** Synopsis:  rowset(P1)=r[P2]
 **
 ** Insert the integer value held by register P2 into a boolean index
 ** held in register P1.
@@ -4992,6 +5062,7 @@ case OP_RowSetAdd: {       /* in1, in2 */
 }
 
 /* Opcode: RowSetRead P1 P2 P3 * *
+** Synopsis:  r[P3]=rowset(P1)
 **
 ** Extract the smallest value from boolean index P1 and put that value into
 ** register P3.  Or, if boolean index P1 is initially empty, leave P3
@@ -5015,6 +5086,7 @@ case OP_RowSetRead: {       /* jump, in1, out3 */
 }
 
 /* Opcode: RowSetTest P1 P2 P3 P4
+** Synopsis: if r[P3] in rowset(P1) goto P2
 **
 ** Register P3 is assumed to hold a 64-bit integer value. If register P1
 ** contains a RowSet object and that RowSet object contains
@@ -5218,6 +5290,7 @@ case OP_Param: {           /* out2-prerelease */
 
 #ifndef SQLITE_OMIT_FOREIGN_KEY
 /* Opcode: FkCounter P1 P2 * * *
+** Synopsis: fkctr[P1]+=P2
 **
 ** Increment a "constraint counter" by P2 (P2 may be negative or positive).
 ** If P1 is non-zero, the database constraint counter is incremented 
@@ -5236,6 +5309,7 @@ case OP_FkCounter: {
 }
 
 /* Opcode: FkIfZero P1 P2 * * *
+** Synopsis: if fkctr[P1]==0 goto P2
 **
 ** This opcode tests if a foreign key constraint-counter is currently zero.
 ** If so, jump to instruction P2. Otherwise, fall through to the next 
@@ -5258,6 +5332,7 @@ case OP_FkIfZero: {         /* jump */
 
 #ifndef SQLITE_OMIT_AUTOINCREMENT
 /* Opcode: MemMax P1 P2 * * *
+** Synopsis: r[P1]=max(r[P1],r[P2])
 **
 ** P1 is a register in the root frame of this VM (the root frame is
 ** different from the current frame if this instruction is being executed
@@ -5288,6 +5363,7 @@ case OP_MemMax: {        /* in2 */
 #endif /* SQLITE_OMIT_AUTOINCREMENT */
 
 /* Opcode: IfPos P1 P2 * * *
+** Synopsis: if r[P1]>0 goto P2
 **
 ** If the value of register P1 is 1 or greater, jump to P2.
 **
@@ -5304,6 +5380,7 @@ case OP_IfPos: {        /* jump, in1 */
 }
 
 /* Opcode: IfNeg P1 P2 * * *
+** Synopsis: if r[P1]<0 goto P2
 **
 ** If the value of register P1 is less than zero, jump to P2. 
 **
@@ -5320,6 +5397,7 @@ case OP_IfNeg: {        /* jump, in1 */
 }
 
 /* Opcode: IfZero P1 P2 P3 * *
+** Synopsis: r[P1]+=P3, if r[P1]==0 goto P2
 **
 ** The register P1 must contain an integer.  Add literal P3 to the
 ** value in register P1.  If the result is exactly 0, jump to P2. 
@@ -5338,6 +5416,7 @@ case OP_IfZero: {        /* jump, in1 */
 }
 
 /* Opcode: AggStep * P2 P3 P4 P5
+** Synopsis: accum=r[P3] step(r[P2]..) N=P5
 **
 ** Execute the step function for an aggregate.  The
 ** function has P5 arguments.   P4 is a pointer to the FuncDef
@@ -5401,6 +5480,7 @@ case OP_AggStep: {
 }
 
 /* Opcode: AggFinal P1 P2 * P4 *
+** Synopsis: accum=r[P1] N=P2
 **
 ** Execute the finalizer function for an aggregate.  P1 is
 ** the memory location that is the accumulator for the aggregate.
@@ -5628,6 +5708,7 @@ case OP_Expire: {
 
 #ifndef SQLITE_OMIT_SHARED_CACHE
 /* Opcode: TableLock P1 P2 P3 P4 *
+** Synopsis: iDb=P1 root=P2 write=P3
 **
 ** Obtain a lock on a particular table. This instruction is only used when
 ** the shared-cache feature is enabled. 
@@ -5744,6 +5825,7 @@ case OP_VOpen: {
 
 #ifndef SQLITE_OMIT_VIRTUALTABLE
 /* Opcode: VFilter P1 P2 P3 P4 *
+** Synopsis: iPlan=r[P3] zPlan='P4'
 **
 ** P1 is a cursor opened using VOpen.  P2 is an address to jump to if
 ** the filtered result set is empty.
@@ -5818,6 +5900,7 @@ case OP_VFilter: {   /* jump */
 
 #ifndef SQLITE_OMIT_VIRTUALTABLE
 /* Opcode: VColumn P1 P2 P3 * *
+** Synopsis: r[P3]=vcolumn(P2)
 **
 ** Store the value of the P2-th column of
 ** the row of the virtual-table that the 
@@ -5951,6 +6034,7 @@ case OP_VRename: {
 
 #ifndef SQLITE_OMIT_VIRTUALTABLE
 /* Opcode: VUpdate P1 P2 P3 P4 *
+** Synopsis: data=r[P3] N=P2
 **
 ** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
 ** This opcode invokes the corresponding xUpdate method. P2 values
diff --git a/src/vdbeaux.c b/src/vdbeaux.c
index ee57392690..c71b29caff 100644
--- a/src/vdbeaux.c
+++ b/src/vdbeaux.c
@@ -856,6 +856,60 @@ VdbeOp *sqlite3VdbeGetOp(Vdbe *p, int addr){
   }
 }
 
+#if defined(SQLITE_DEBUG)
+/*
+** Compute a string for the "comment" field of a VDBE opcode listing
+*/
+static int displayComment(Op *pOp, const char *zP4, char *zTemp, int nTemp){
+  const char *zOpName;
+  const char *zSynopsis;
+  int nOpName;
+  int ii, jj;
+  zOpName = sqlite3OpcodeName(pOp->opcode);
+  nOpName = sqlite3Strlen30(zOpName);
+  if( zOpName[nOpName+1] ){
+    int seenCom = 0;
+    zSynopsis = zOpName += nOpName + 1;
+    for(ii=jj=0; jj<nTemp-1 && zSynopsis[ii]; ii++){
+      if( zSynopsis[ii]=='P' ){
+        int v;
+        const char *zShow = 0;
+        ii++;
+        switch( zSynopsis[ii] ){
+          case '1': v = pOp->p1;  break;
+          case '2': v = pOp->p2;  break;
+          case '3': v = pOp->p3;  break;
+          case '5': v = pOp->p5;  break;
+          case '4': zShow = zP4;  break;
+          case 'X': zShow = pOp->zComment; seenCom = 1; break;
+        }
+        if( zShow ){
+          sqlite3_snprintf(nTemp-jj, zTemp+jj, "%s", zShow);
+        }else{
+          sqlite3_snprintf(nTemp-jj, zTemp+jj, "%d", v);
+        }
+        jj += sqlite3Strlen30(zTemp+jj);
+      }else{
+        zTemp[jj++] = zSynopsis[ii];
+      }
+    }
+    if( !seenCom && jj<nTemp-5 && pOp->zComment ){
+      sqlite3_snprintf(nTemp-jj, zTemp+jj, "; %s", pOp->zComment);
+      jj += sqlite3Strlen30(zTemp+jj);
+    }
+    if( jj<nTemp ) zTemp[jj] = 0;
+  }else if( pOp->zComment ){
+    sqlite3_snprintf(nTemp, zTemp, "%s", pOp->zComment);
+    jj = sqlite3Strlen30(zTemp);
+  }else{
+    zTemp[0] = 0;
+    jj = 0;
+  }
+  return jj;
+}
+#endif /* SQLITE_DEBUG */
+
+
 #if !defined(SQLITE_OMIT_EXPLAIN) || !defined(NDEBUG) \
      || defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
 /*
@@ -1049,16 +1103,18 @@ void sqlite3VdbeLeave(Vdbe *p){
 void sqlite3VdbePrintOp(FILE *pOut, int pc, Op *pOp){
   char *zP4;
   char zPtr[50];
+  char zCom[100];
   static const char *zFormat1 = "%4d %-13s %4d %4d %4d %-4s %.2X %s\n";
   if( pOut==0 ) pOut = stdout;
   zP4 = displayP4(pOp, zPtr, sizeof(zPtr));
+#ifdef SQLITE_DEBUG
+  displayComment(pOp, zP4, zCom, sizeof(zCom));
+#else
+  zCom[0] = 0
+#endif
   fprintf(pOut, zFormat1, pc, 
       sqlite3OpcodeName(pOp->opcode), pOp->p1, pOp->p2, pOp->p3, zP4, pOp->p5,
-#ifdef SQLITE_DEBUG
-      pOp->zComment ? pOp->zComment : ""
-#else
-      ""
-#endif
+      zCom
   );
   fflush(pOut);
 }
@@ -1204,7 +1260,7 @@ int sqlite3VdbeList(
     rc = SQLITE_ERROR;
     sqlite3SetString(&p->zErrMsg, db, "%s", sqlite3ErrStr(p->rc));
   }else{
-    char *z;
+    char *zP4;
     Op *pOp;
     if( i<p->nOp ){
       /* The output line number is small enough that we are still in the
@@ -1227,7 +1283,7 @@ int sqlite3VdbeList(
       pMem++;
   
       pMem->flags = MEM_Static|MEM_Str|MEM_Term;
-      pMem->z = (char*)sqlite3OpcodeName(pOp->opcode);  /* Opcode */
+      pMem->z = (char*)sqlite3OpcodeName(pOp->opcode); /* Opcode */
       assert( pMem->z!=0 );
       pMem->n = sqlite3Strlen30(pMem->z);
       pMem->type = SQLITE_TEXT;
@@ -1274,9 +1330,9 @@ int sqlite3VdbeList(
       return SQLITE_ERROR;
     }
     pMem->flags = MEM_Dyn|MEM_Str|MEM_Term;
-    z = displayP4(pOp, pMem->z, 32);
-    if( z!=pMem->z ){
-      sqlite3VdbeMemSetStr(pMem, z, -1, SQLITE_UTF8, 0);
+    zP4 = displayP4(pOp, pMem->z, 32);
+    if( zP4!=pMem->z ){
+      sqlite3VdbeMemSetStr(pMem, zP4, -1, SQLITE_UTF8, 0);
     }else{
       assert( pMem->z!=0 );
       pMem->n = sqlite3Strlen30(pMem->z);
@@ -1298,18 +1354,18 @@ int sqlite3VdbeList(
       pMem++;
   
 #ifdef SQLITE_DEBUG
-      if( pOp->zComment ){
-        pMem->flags = MEM_Str|MEM_Term;
-        pMem->z = pOp->zComment;
-        pMem->n = sqlite3Strlen30(pMem->z);
-        pMem->enc = SQLITE_UTF8;
-        pMem->type = SQLITE_TEXT;
-      }else
-#endif
-      {
-        pMem->flags = MEM_Null;                       /* Comment */
-        pMem->type = SQLITE_NULL;
+      if( sqlite3VdbeMemGrow(pMem, 500, 0) ){
+        assert( p->db->mallocFailed );
+        return SQLITE_ERROR;
       }
+      pMem->flags = MEM_Dyn|MEM_Str|MEM_Term;
+      pMem->n = displayComment(pOp, zP4, pMem->z, 500);
+      pMem->type = SQLITE_TEXT;
+      pMem->enc = SQLITE_UTF8;
+#else
+      pMem->flags = MEM_Null;                       /* Comment */
+      pMem->type = SQLITE_NULL;
+#endif
     }
 
     p->nResColumn = 8 - 4*(p->explain-1);