diff --git a/ext/misc/spellfix.c b/ext/misc/spellfix.c
index 1966d554e7..28374b8cc2 100644
--- a/ext/misc/spellfix.c
+++ b/ext/misc/spellfix.c
@@ -691,6 +691,7 @@ static int editDist3ConfigLoad(
     assert( zTo!=0 || nTo==0 );
     if( nFrom>100 || nTo>100 ) continue;
     if( iCost<0 ) continue;
+    if( iCost>10000 ) continue;   /* Costs above 10K are considered infinite */
     if( pLang==0 || iLang!=iLangPrev ){
       EditDist3Lang *pNew;
       pNew = sqlite3_realloc64(p->a, (p->nLang+1)*sizeof(p->a[0]));
@@ -782,7 +783,7 @@ static int matchFromTo(
 ){
   int b1 = pStr->a[n1].nByte;
   if( b1>n2 ) return 0;
-  if( memcmp(pStr->z+n1, z2, b1)!=0 ) return 0;
+  if( strncmp(pStr->z+n1, z2, b1)!=0 ) return 0;
   return 1;
 }
 
@@ -864,9 +865,6 @@ static EditDist3FromString *editDist3FromStringNew(
 /*
 ** Update entry m[i] such that it is the minimum of its current value
 ** and m[j]+iCost.
-**
-** If the iCost is 1,000,000 or greater, then consider the cost to be
-** infinite and skip the update.
 */
 static void updateCost(
   unsigned int *m,
@@ -874,11 +872,11 @@ static void updateCost(
   int j,
   int iCost
 ){
+  unsigned int b;
   assert( iCost>=0 );
-  if( iCost<10000 ){
-    unsigned int b = m[j] + iCost;
-    if( b<m[i] ) m[i] = b;
-  }
+  assert( iCost<10000 );
+  b = m[j] + iCost;
+  if( b<m[i] ) m[i] = b;
 }
 
 /*
diff --git a/manifest b/manifest
index 09759a8b0f..13a742a2be 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Disable\sassert()\sin\sthe\sspellfix\sextension\sif\snot\scompiled\swith\sSQLITE_DEBUG.
-D 2018-02-14T20:25:33.844
+C Performance\soptimizations\sto\sthe\seditdist3()\sfunction\sin\sthe\sspellfix\nextension.
+D 2018-02-14T20:58:36.311
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F Makefile.in 7a3f714b4fcf793108042b7b0a5c720b0b310ec84314d61ba7f3f49f27e550ea
@@ -294,7 +294,7 @@ F ext/misc/series.c f3c0dba5c5c749ce1782b53076108f87cf0b71041eb6023f727a9c50681d
 F ext/misc/sha1.c 0b9e9b855354910d3ca467bf39099d570e73db56
 F ext/misc/shathree.c 9e960ba50483214c6a7a4b1517f8d8cef799e9db381195178c3fd3ad207e10c0
 F ext/misc/showauth.c 732578f0fe4ce42d577e1c86dc89dd14a006ab52
-F ext/misc/spellfix.c bb73be37491fd5007efab8dfd8ac416315d47f8aba99179b8adb4255e85c7ff5
+F ext/misc/spellfix.c fcf23b0746bfefbec46a54cfb2cd0720c442a6e382247b4049748f882ad26b94
 F ext/misc/sqlar.c 57d5bc45cd5492208e451f697404be88f8612527d64c9d42f96b325b64983d74
 F ext/misc/stmt.c 6f16443abb3551e3f5813bb13ba19a30e7032830015b0f92fe0c0453045c0a11
 F ext/misc/totype.c 4a167594e791abeed95e0a8db028822b5e8fe512
@@ -1706,7 +1706,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 2d3f1f22d53034576a0ec8d9c360fb19efbb05b2e95ad1b09d120fb1b7da33fd
-R 4aff58b3b0f19d8824c9d78629ce8a88
+P 3c53ee0fdea4cbf2590e2b289b021b0ef8b7ead2945db1bdfc767432d9447acb
+R 52a6749d61b6207535a693308aa98655
 U drh
-Z bdffc86a194b9f42419156834dd68b1f
+Z c6d9011f82c1274dfef70231bb03befb
diff --git a/manifest.uuid b/manifest.uuid
index 129d553977..8a40d27ca4 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-3c53ee0fdea4cbf2590e2b289b021b0ef8b7ead2945db1bdfc767432d9447acb
\ No newline at end of file
+70d304dcbac4c3fd5e3b96108bffea2ce6c0db19c847397d5c5e268bb90a981d
\ No newline at end of file