Adjust the query planner to take into account WHERE clause terms that do not

drive indices.  Add the unlikely() and likelihood() functions used to give
hints to the query planner about the selectivity of WHERE clause terms.

FossilOrigin-Name: bc446449a19171c0fa0681973b06bc80d3c0517f

diff --cc manifest
index 4754d70f3461fe440dcd8b88627309b6fff13afd,f8d28e34a8c157fb36bbca157e174f835ecea7e0..6f7f939043a7a2e34601d81ad1cf79239293add6
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Enhance\sthe\spragma\slookup\stable\sgenerator\sscript\sto\soutput\sa\scomment\sthat\ngives\sthe\snumber\sof\spragmas.
- D 2013-09-13T16:56:17.293
 -C Refactor\sthe\sExprSetIrreducible()\smacro\sinto\sExprSetVVAProperty(*,EP_NoReduce).\nThis\sis\sa\snaming\schange\sonly.\s\sThe\slogic\sis\sthe\ssame.
 -D 2013-09-12T23:42:22.354
++C Adjust\sthe\squery\splanner\sto\stake\sinto\saccount\sWHERE\sclause\sterms\sthat\sdo\snot\ndrive\sindices.\s\sAdd\sthe\sunlikely()\sand\slikelihood()\sfunctions\sused\sto\sgive\nhints\sto\sthe\squery\splanner\sabout\sthe\sselectivity\sof\sWHERE\sclause\sterms.
++D 2013-09-13T17:47:57.412
  F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
  F Makefile.in 5e41da95d92656a5004b03d3576e8b226858a28e
  F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@@ -172,10 -172,10 +172,10 @@@ F src/complete.c dc1d136c0feee03c2f7550
  F src/ctime.c ea4b7f3623a0fcb1146e7f245d7410033e86859c
  F src/date.c 067a81c9942c497aafd2c260e13add8a7d0c7dd4
  F src/delete.c 2dc64ca360b7d7da481183ea920a813a0c203c97
- F src/expr.c 33ae44812d25799000dbcfd54bb2142b30cdd049
+ F src/expr.c 58ffffbb83d2bbf59c6a7a080cf6622a1ddbf264
  F src/fault.c 160a0c015b6c2629d3899ed2daf63d75754a32bb
  F src/fkey.c be866cd8c4fa6cae98ba33109578fd1a3311ee5b
- F src/func.c be8482e92e70560e127b55a989663c0689c657cd
 -F src/func.c 0aca17c8bc750fad4856e6098ed5e2597b641a75
++F src/func.c 2c47b65e6e00e3e9374942f28254faf8adafe398
  F src/global.c 5caf4deab621abb45b4c607aad1bd21c20aac759
  F src/hash.c ac3470bbf1ca4ae4e306a8ecb0fdf1731810ffe4
  F src/hash.h 8890a25af81fb85a9ad7790d32eedab4b994da22
@@@ -1113,7 -1113,7 +1114,7 @@@ F tool/warnings-clang.sh f6aa929dc20ef1
  F tool/warnings.sh fbc018d67fd7395f440c28f33ef0f94420226381
  F tool/wherecosttest.c f407dc4c79786982a475261866a161cd007947ae
  F tool/win/sqlite.vsix 97894c2790eda7b5bce3cc79cb2a8ec2fde9b3ac
- P 870c030b4e1854e6e0d39907fadbd82774c16f56
- R 8afb65d113bbf2b92c215847e16c4a85
 -P 4c84d1b4c20f18921dd705bf67e8225975b83e86
 -R a4ae742117959f8b867f4728cbf6ae0f
++P ca05205050752b5d5f583421b7813fba62f5085c 695aee46e9bdf15159ab52db7f522b30c91aed0f
++R 980cfef5e90de5b8a20e59163235b5ab
  U drh
- Z 4c8308b89b9a52a9fa36455ebe75f0fa
 -Z 5e782298e284a317de441c3b3e41bc0d
++Z 7155733e1fc2738b458062a357e01575

diff --cc manifest.uuid
index 773f07f87ed39d2b1d71f75df2720887e50ee8c5,56a7606a6cdf9eb71e24cea96335a196ef91420e..6c1b6e74c33522d22e8cd29b3b4f117d5f5e21ed
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- ca05205050752b5d5f583421b7813fba62f5085c
 -695aee46e9bdf15159ab52db7f522b30c91aed0f
++bc446449a19171c0fa0681973b06bc80d3c0517f

diff --cc src/func.c
Simple merge