Attempt to use STAT4 information to estimate the selectivity of WHERE clause

terms when using the skip-scan optimization.

FossilOrigin-Name: d09ca6d5efad3e4cfa93a4dc711e6ba6079d4b4b

diff --cc manifest
index 08281d94677cb4d6224232888a1e82e6f8acd461,84b9befd7b77a4d11d6b5ee242c96110c51a105e..bbfeca06e9848a8151a32b724ab3990a30191f63
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,9 -1,9 +1,9 @@@
- C Fix\sfor\sticket\s[b2fa5424e6fcb15]:\sBetter\sdefine\sthe\sformat\sof\sthe\ssqlite_stat4\nfile\sfor\sWITHOUT\sROWID\stables\sand\smake\ssure\sthe\sANALYZE\scommand\sgenerates\sa\nfile\sin\sthe\sappropriate\sformat.\s\sUse\sthe\ssqlite_stat4\sdata\sto\senable\sthe\suse\nof\sWHERE\sterms\sthat\scover\sall\sindexed\scolumns\splus\ssome\sprefix\sof\scolumns\nin\sthe\sprimary\skey.
- D 2014-06-30T18:57:53.330
 -C Add\san\sOOM\sfault\sinjection\stest\sfor\sthe\snew\scode\son\sthis\sbranch.
 -D 2014-06-28T19:06:49.846
++C Attempt\sto\suse\sSTAT4\sinformation\sto\sestimate\sthe\sselectivity\sof\sWHERE\sclause\nterms\swhen\susing\sthe\sskip-scan\soptimization.
++D 2014-06-30T19:07:58.197
  F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 -F Makefile.in b03432313a3aad96c706f8164fb9f5307eaf19f5
 +F Makefile.in 1732320ecac3fee229d560d7ef2afa34681d1815
  F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
 -F Makefile.msc b2d3ac211b479fa5a6c9aaf3b9c49fdea900d228
 +F Makefile.msc ad60c4d8be35f98fdcca614088b84a91612b2b4c
  F Makefile.vxworks 034289efa9d591b04b1a73598623119c306cbba0
  F README.md 64f270c43c38c46de749e419c22f0ae2f4499fe8
  F VERSION 9f823c026c6a32fc5f84d212a8aae0a221dba45c
@@@ -296,7 -296,7 +296,7 @@@ F src/vtab.c 21b932841e51ebd7d075e2d0ad
  F src/wal.c 264df50a1b33124130b23180ded2e2c5663c652a
  F src/wal.h df01efe09c5cb8c8e391ff1715cca294f89668a4
  F src/walker.c 11edb74d587bc87b33ca96a5173e3ec1b8389e45
- F src/where.c 2bc0226fced128686c432748324351beb127829b
 -F src/where.c 84659c308426b20be4efada82a06a26dd6b8545e
++F src/where.c 6ff6f7e3b272fad66eea601af489777adea3cc1f
  F src/whereInt.h 929c1349b5355fd44f22cee5c14d72b3329c58a6
  F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
  F test/aggerror.test a867e273ef9e3d7919f03ef4f0e8c0d2767944f2
@@@ -1181,8 -1182,7 +1182,8 @@@ F tool/vdbe_profile.tcl 67746953071a9f8
  F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
  F tool/warnings.sh 0abfd78ceb09b7f7c27c688c8e3fe93268a13b32
  F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
- P 6f86d89b8800c50035da7809bff941d08a33a6a2 053a210e3169732c58f84cb54c9b6f6df3a8f4ea
- R 48fee5f306f007e5e5bc0779449b568d
- T +closed 053a210e3169732c58f84cb54c9b6f6df3a8f4ea
 -P 4b8230e8fe93e73a615a46708aed5fa3557b6228
 -R 626c4988935b78bcb3d2f8f34291bc5b
 -U dan
 -Z 19d12a554b06297187fc9a292703f2d4
++P bc2de8095fa9c385db0adf22ca55b0298a33c284 c96de490ac77dd23c108004b95152cce4922fe27
++R 55c9ac9304448ee4805a54515b7a2134
++T +closed c96de490ac77dd23c108004b95152cce4922fe27
 +U drh
- Z b0031b3eff85f5d5ff26a8a2fea67c94
++Z bab166b6f1bf8cfb185d9041a405176e

diff --cc manifest.uuid
index acf097220d53ef2885fd28cd08d8bca44aa9b000,d74a6bd2f908019a6afa4b6a3c9acec1bcd6538c..91daee692f174e575ff042a19311b395e6655d0d
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- bc2de8095fa9c385db0adf22ca55b0298a33c284
 -c96de490ac77dd23c108004b95152cce4922fe27
++d09ca6d5efad3e4cfa93a4dc711e6ba6079d4b4b

diff --cc src/where.c
Simple merge