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.

FossilOrigin-Name: 3b964155f611c437d53d44feafa22f531942b1b4

src/sqliteInt.h

@@ -1462,6 +1462,7 @@ 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 */