If the keyword "unordered" appears at the end of the SQLITE_STAT1.STAT

column for an index, then use that index for equality lookups only, never 
for range queries or sorting.  This feature is currently undocumented and
my change or be removed in a future release.

FossilOrigin-Name: 8a42e236701c8afd9ada7d4568712a21690ea087

manifest

@@ -1,5 +1,5 @@
-C Back\sout\sthe\sSQLITE_OMIT_UNIQUE_ENFORCEMENT\scompile-option.\s\sIt\sis\san\sunneeded\ncomplication.
-D 2011-04-09T03:04:13.095
+C If\sthe\skeyword\s"unordered"\sappears\sat\sthe\send\sof\sthe\sSQLITE_STAT1.STAT\s\ncolumn\sfor\san\sindex,\sthen\suse\sthat\sindex\sfor\sequality\slookups\sonly,\snever\s\nfor\srange\squeries\sor\ssorting.\s\sThis\sfeature\sis\scurrently\sundocumented\sand\nmy\schange\sor\sbe\sremoved\sin\sa\sfuture\srelease.
+D 2011-04-09T03:20:59.281
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 7a4d9524721d40ef9ee26f93f9bd6a51dba106f2
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -115,7 +115,7 @@ F sqlite.pc.in 42b7bf0d02e08b9e77734a47798d1a55a9e0716b
 F sqlite3.1 6be1ad09113570e1fc8dcaff84c9b0b337db5ffc
 F sqlite3.pc.in ae6f59a76e862f5c561eb32a380228a02afc3cad
 F src/alter.c 280f5c04b11b492703a342222b3de0a999445280
-F src/analyze.c a1ad9f4d8aac055c4a4bbd99073e2e78fe66129c
+F src/analyze.c a425d62e8fa9ebcb4359ab84ff0c62c6563d2e2a
 F src/attach.c 7f97ca76ef2453440170929531a9c778267c0830
 F src/auth.c 523da7fb4979469955d822ff9298352d6b31de34
 F src/backup.c 8d738af17e87eb6fcf2dab8b26153a918a114e48
@@ -180,7 +180,7 @@ F src/select.c 649a6f10f7eb7b52a5a28847773cb9968a828ae8
 F src/shell.c 9c8389796764f65d4506bcd614ac8061f4160d5c
 F src/sqlite.h.in 4d28db70c37a1b17942820308eb59f211140da43
 F src/sqlite3ext.h c90bd5507099f62043832d73f6425d8d5c5da754
-F src/sqliteInt.h 7b0150bfdab049b11bb2d055d065051ff734d113
+F src/sqliteInt.h 9e53256aa7cb22ed2126c5350bc25e96bc7c4ed8
 F src/sqliteLimit.h 164b0e6749d31e0daa1a4589a169d31c0dec7b3d
 F src/status.c 7ac64842c86cec2fc1a1d0e5c16d3beb8ad332bf
 F src/table.c 2cd62736f845d82200acfa1287e33feb3c15d62e
@@ -247,7 +247,7 @@ F src/vtab.c b0abc931f95af94c9ffdf9f747eb191cda953123
 F src/wal.c 7334009b396285b658a95a3b6bc6d2b016a1f794
 F src/wal.h 7a5fbb00114b7f2cd40c7e1003d4c41ce9d26840
 F src/walker.c 3112bb3afe1d85dc52317cb1d752055e9a781f8f
-F src/where.c 494d106959a492838ab3723e284de46ddd520da1
+F src/where.c 55403ce19c506be6a321c7f129aff693d6103db5
 F test/aggerror.test a867e273ef9e3d7919f03ef4f0e8c0d2767944f2
 F test/alias.test 4529fbc152f190268a15f9384a5651bbbabc9d87
 F test/all.test 51756962d522e474338e9b2ebb26e7364d4aa125
@@ -926,7 +926,7 @@ F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/split-sqlite3c.tcl d9be87f1c340285a3e081eb19b4a247981ed290c
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
-P 4caa5fc86e7fe404cd188713277f2801cd02dbc9
-R 7c13920af52add3fb4004361c1b744b2
+P 927e955b93e869727c55b784401de3ea07bee257 3b964155f611c437d53d44feafa22f531942b1b4
+R 8f730b36ea51ef307e60876151b20fbc
 U drh
-Z f0a05ecbdcea6caa1b19a9a2e8b6f008
+Z ad8576a5ee09c7cb93d286363cb1b8eb

manifest.uuid

@@ -1 +1 @@
-927e955b93e869727c55b784401de3ea07bee257
+8a42e236701c8afd9ada7d4568712a21690ea087

src/analyze.c

@@ -548,6 +548,10 @@ static int analysisLoader(void *pData, int argc, char **argv, char **NotUsed){
     if( pIndex==0 ) break;
     pIndex->aiRowEst[i] = v;
     if( *z==' ' ) z++;
+    if( memcmp(z, "unordered", 10)==0 ){
+      pIndex->bUnordered = 1;
+      break;
+    }
   }
   return 0;
 }

src/sqliteInt.h

@@ -1476,6 +1476,7 @@ struct Index {
   int tnum;        /* Page containing root of this index in database file */
   u8 onError;      /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
   u8 autoIndex;    /* True if is automatically created (ex: by UNIQUE) */
+  u8 bUnordered;   /* Use this index for == or IN queries only */
   char *zColAff;   /* String defining the affinity of each column */
   Index *pNext;    /* The next index associated with the same table */
   Schema *pSchema; /* Schema containing this index */

src/where.c

@@ -2863,7 +2863,7 @@ static void bestBtreeIndex(
     }
 
     /* Determine the value of estBound. */
-    if( nEq<pProbe->nColumn ){
+    if( nEq<pProbe->nColumn && pProbe->bUnordered==0 ){
       int j = pProbe->aiColumn[nEq];
       if( findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE|WO_GT|WO_GE, pIdx) ){
         WhereTerm *pTop = findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE, pIdx);
@@ -2895,6 +2895,7 @@ static void bestBtreeIndex(
     ** will scan rows in a different order, set the bSort variable.  */
     if( pOrderBy ){
       if( (wsFlags & WHERE_COLUMN_IN)==0
+        && pProbe->bUnordered==0
         && isSortingIndex(pParse, pWC->pMaskSet, pProbe, iCur, pOrderBy,
                           nEq, wsFlags, &rev)
       ){