In order to optimize out the ORDER BY clause,

outer loops must generate values for ORDER BY terms that are unique or else
the inner loops must generate no more than a single row.
Fix for ticket [a179fe7465].

FossilOrigin-Name: 2936f7466e162dfb003bda26d35358d1b3063112

diff --cc manifest
index 007356f17667d06a34f56e457da07ebbce367332,5f6aa42e1a6bb6d2891006c0cb134b12a9fffb01..d1bf95f8202c13bf22b7c34d471f0aab01bb9edf
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Candidate\sfix\sfor\sticket\s[6bfb98dfc0c]:\sMake\ssure\sinvalid\scursors\sdrop\sall\nreferences\sto\sdatabase\spages\sprior\sto\sdoing\sany\sinsert\sor\supdate.
- D 2013-03-27T03:15:23.329
 -C Restore\sadditional\sORDER\sBY\soptimizations\sthat\swhere\sbroken\sby\sthe\nrecent\sORDER\sBY\sfix.
 -D 2013-03-27T16:42:21.685
++C In\sorder\sto\soptimize\sout\sthe\sORDER\sBY\sclause,\s\nouter\sloops\smust\sgenerate\svalues\sfor\sORDER\sBY\sterms\sthat\sare\sunique\sor\selse\nthe\sinner\sloops\smust\sgenerate\sno\smore\sthan\sa\ssingle\srow.\nFix\sfor\sticket\s[a179fe7465].
++D 2013-03-27T17:20:10.024
  F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
  F Makefile.in df3e48659d80e1b7765785d8d66c86b320f72cc7
  F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@@ -252,7 -252,7 +252,7 @@@ F src/vtab.c b05e5f1f4902461ba9f5fc49bb
  F src/wal.c f5c7b5027d0ed0e9bc9afeb4a3a8dfea762ec7d2
  F src/wal.h 29c197540b19044e6cd73487017e5e47a1d3dac6
  F src/walker.c 3d75ba73de15e0f8cd0737643badbeb0e002f07b
- F src/where.c 9a16c0b84bbeb054d11fda96e9e037ae310bd54e
 -F src/where.c 8179f4c891d2742ff7c00237b2f7b534c826503c
++F src/where.c 4ad2329c439a30ddb915a780f6f80bdffafe3a64
  F test/8_3_names.test 631ea964a3edb091cf73c3b540f6bcfdb36ce823
  F test/aggerror.test a867e273ef9e3d7919f03ef4f0e8c0d2767944f2
  F test/aggnested.test 45c0201e28045ad38a530b5a144b73cd4aa2cfd6
@@@ -1040,7 -1041,7 +1041,7 @@@ F tool/vdbe-compress.tcl f12c884766bd14
  F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
  F tool/warnings.sh fbc018d67fd7395f440c28f33ef0f94420226381
  F tool/win/sqlite.vsix 97894c2790eda7b5bce3cc79cb2a8ec2fde9b3ac
- P 5062db672c00c3365d51cd6b39815078f5b6b525
- R 444ec66222f6e3876b5a1bc78bf6602c
 -P 97e5c70f2f19a1bca70dd2221b757b9e5418fce0
 -R 4ded79a01068c5e1c5e1e2eba18cd5f5
++P 322a5f086d9ee46017f750df81527799a54ae258 c77ee6e20d3a8c91a8bf4c9063c36a95c70e17cf
++R 7a3bcce0c2bcd988dcd25474f2b83a5d
  U drh
- Z 3d135e15ecdab16eb6decd45c9d13940
 -Z 80c245e483b26492a6a00ec636bab1bb
++Z 25cf293fe59d9bbc42bbcd9448a91b58

diff --cc manifest.uuid
index ed40effb49f51a1a73d71b5884e1772114693f7c,ac70cc5249705f9604278c5c724dacc192f01b0d..8b756b39527410ec6b4d3f112c8d5aa8182d769f
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 322a5f086d9ee46017f750df81527799a54ae258
 -c77ee6e20d3a8c91a8bf4c9063c36a95c70e17cf
++2936f7466e162dfb003bda26d35358d1b3063112

diff --cc src/where.c
index 9b64fd72fe60112e028cc326e8bc44315bcc5e41,5c0f664aece857254867258d99039f5e0008b3f6..bd8a7541fa60f0c3a6612cae59f49407f34eb876
--- 1/src/where.c
--- 2/src/where.c
+++ b/src/where.c
@@@ -3078,6 -3093,10 +3093,16 @@@ static int isSortingIndex
    ** index, then show no progress. */
    if( pOBItem==&pOrderBy->a[nPriorSat] ) return nPriorSat;
  
 -  /* */  
++  /* Either the outer queries must generate rows where there are no two
++  ** rows with the same values in all ORDER BY columns, or else this
++  ** loop must generate just a single row of output.  Example:  Suppose
++  ** the outer loops generate A=1 and A=1, and this loop generates B=3
++  ** and B=4.  Then without the following test, ORDER BY A,B would 
++  ** generate the wrong order output: 1,3 1,4 1,3 1,4
++  */
+   if( outerObUnique==0 && uniqueNotNull==0 ) return nPriorSat;
+   *pbObUnique = uniqueNotNull;
+ 
    /* Return the necessary scan order back to the caller */
    *pbRev = sortOrder & 1;