diff --git a/manifest b/manifest
index 9c937841a0..f7b1f32f51 100644
--- a/manifest
+++ b/manifest
@@ -1,8 +1,8 @@
 -----BEGIN PGP SIGNED MESSAGE-----
 Hash: SHA1
 
-C Allow\smedia\ssector\ssizes\sas\ssmall\sas\s32.\s\sThe\sformer\sminimum\ssize\swas\s512.
-D 2009-11-11T13:17:08
+C Tweaks\sto\sthe\sSUBSTR()\sfunction\sto\smake\sit\sdramatically\sfaster\sin\sthe\scommon\ncase\swhere\sthe\sinput\sstring\sis\slarge\sbut\sthe\s2nd\sand\s3rd\sarguments\sare\ssmall\npositive\sintegers.
+D 2009-11-11T20:53:31
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in 53f3dfa49f28ab5b80cb083fb7c9051e596bcfa1
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -120,7 +120,7 @@ F src/delete.c ec04635d152debdab70d4b30c5516b59282075ea
 F src/expr.c be605c60ff84699f3087209f2f86a140a6a5e96c
 F src/fault.c 160a0c015b6c2629d3899ed2daf63d75754a32bb
 F src/fkey.c 41219cba186bcf0a053e42327dfa23aaba4f834a
-F src/func.c 5949e2633bb8ff57cc70c1904db171ba23f13537
+F src/func.c 97cb15ef7a7c32293a938589c9eb6933f6688a21
 F src/global.c 271952d199a8cc59d4ce840b3bbbfd2f30c8ba32
 F src/hash.c 458488dcc159c301b8e7686280ab209f1fb915af
 F src/hash.h 2894c932d84d9f892d4b4023a75e501f83050970
@@ -770,14 +770,14 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
-P 09b4f19f100fe82a8321b9ded99e679b7eedc1fa
-R 4660953738e09e48658e726d4ab4929b
+P 5a32bfc17ed022c85d2615c34b41a3dcae2594bd
+R 40ba71f59fe4e9d89ef2ec58e5f61b4f
 U drh
-Z eb38c72c7392595b8c9af9da37273b2d
+Z 900447894e5e2bfd8a391e7b7ee91c4f
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1.4.6 (GNU/Linux)
 
-iD8DBQFK+rlYoxKgR168RlERAkd5AJ0ZWUnPqChJybXaCT0e1e2vLdOf+ACePwEx
-ifVUs5BZPo6twb6xD420UW4=
-=eW+2
+iD8DBQFK+yROoxKgR168RlERAgxxAKCHj71qH3RTTKkacqnNolY2rfQh3ACfYfTz
+I5+1whsNXmr3GYydKvNnoeA=
+=f867
 -----END PGP SIGNATURE-----
diff --git a/manifest.uuid b/manifest.uuid
index 00cbd83489..b8542ab814 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-5a32bfc17ed022c85d2615c34b41a3dcae2594bd
\ No newline at end of file
+5a474a867c5988ad5ec03719516fdd38f0da5c2c
\ No newline at end of file
diff --git a/src/func.c b/src/func.c
index 980d04edb6..e1ad9a36cc 100644
--- a/src/func.c
+++ b/src/func.c
@@ -177,6 +177,7 @@ static void substrFunc(
     return;
   }
   p0type = sqlite3_value_type(argv[0]);
+  p1 = sqlite3_value_int(argv[1]);
   if( p0type==SQLITE_BLOB ){
     len = sqlite3_value_bytes(argv[0]);
     z = sqlite3_value_blob(argv[0]);
@@ -186,11 +187,12 @@ static void substrFunc(
     z = sqlite3_value_text(argv[0]);
     if( z==0 ) return;
     len = 0;
-    for(z2=z; *z2; len++){
-      SQLITE_SKIP_UTF8(z2);
+    if( p1<0 ){
+      for(z2=z; *z2; len++){
+        SQLITE_SKIP_UTF8(z2);
+      }
     }
   }
-  p1 = sqlite3_value_int(argv[1]);
   if( argc==3 ){
     p2 = sqlite3_value_int(argv[2]);
     if( p2<0 ){
@@ -220,10 +222,6 @@ static void substrFunc(
     }
   }
   assert( p1>=0 && p2>=0 );
-  if( p1+p2>len ){
-    p2 = len-p1;
-    if( p2<0 ) p2 = 0;
-  }
   if( p0type!=SQLITE_BLOB ){
     while( *z && p1 ){
       SQLITE_SKIP_UTF8(z);
@@ -234,6 +232,10 @@ static void substrFunc(
     }
     sqlite3_result_text(context, (char*)z, (int)(z2-z), SQLITE_TRANSIENT);
   }else{
+    if( p1+p2>len ){
+      p2 = len-p1;
+      if( p2<0 ) p2 = 0;
+    }
     sqlite3_result_blob(context, (char*)&z[p1], (int)p2, SQLITE_TRANSIENT);
   }
 }