SQLite

      case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
      case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
      case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
      case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
      case SQLITE_NOTICE_RECOVER_ROLLBACK:
                                zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
      case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
      case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
      case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
    }
  }
  if( zName==0 ){
    static char zBuf[50];
    sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
    zName = zBuf;

#define SQLITE_CONSTRAINT_NOTNULL      (SQLITE_CONSTRAINT | (5<<8))
#define SQLITE_CONSTRAINT_PRIMARYKEY   (SQLITE_CONSTRAINT | (6<<8))
#define SQLITE_CONSTRAINT_TRIGGER      (SQLITE_CONSTRAINT | (7<<8))
#define SQLITE_CONSTRAINT_UNIQUE       (SQLITE_CONSTRAINT | (8<<8))
#define SQLITE_CONSTRAINT_VTAB         (SQLITE_CONSTRAINT | (9<<8))
#define SQLITE_NOTICE_RECOVER_WAL      (SQLITE_NOTICE | (1<<8))
#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
#define SQLITE_WARNING_AUTOINDEX       (SQLITE_WARNING | (1<<8))

/*
** CAPI3REF: Flags For File Open Operations
**
** These bit values are intended for use in the
** 3rd parameter to the [sqlite3_open_v2()] interface and
** in the 4th parameter to the [sqlite3_vfs.xOpen] method.

  int n;                      /* Column counter */
  int i;                      /* Loop counter */
  int mxBitCol;               /* Maximum column in pSrc->colUsed */
  CollSeq *pColl;             /* Collating sequence to on a column */
  WhereLoop *pLoop;           /* The Loop object */
  Bitmask idxCols;            /* Bitmap of columns used for indexing */
  Bitmask extraCols;          /* Bitmap of additional columns */
  u8 sentWarning = 0;         /* True if a warnning has been issued */

  /* Generate code to skip over the creation and initialization of the
  ** transient index on 2nd and subsequent iterations of the loop. */
  v = pParse->pVdbe;
  assert( v!=0 );
  addrInit = sqlite3CodeOnce(pParse);

  /* Count the number of columns that will be added to the index
  ** and used to match WHERE clause constraints */
  nColumn = 0;
  pTable = pSrc->pTab;
  pWCEnd = &pWC->a[pWC->nTerm];
  pLoop = pLevel->pWLoop;
  idxCols = 0;
  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
    if( termCanDriveIndex(pTerm, pSrc, notReady) ){
      int iCol = pTerm->u.leftColumn;
      Bitmask cMask = iCol>=BMS ? MASKBIT(BMS-1) : MASKBIT(iCol);
      testcase( iCol==BMS );
      testcase( iCol==BMS-1 );
      if( !sentWarning ){
        sqlite3_log(SQLITE_WARNING_AUTOINDEX,
            "automatic index on %s(%s)", pTable->zName,
            pTable->aCol[iCol].zName);
        sentWarning = 1;
      }
      if( (idxCols & cMask)==0 ){
        if( whereLoopResize(pParse->db, pLoop, nColumn+1) ) return;
        pLoop->aLTerm[nColumn++] = pTerm;
        idxCols |= cMask;
      }
    }
  }

# If the library is not compiled with automatic index support then
# skip all tests in this file.
#
ifcapable {!autoindex} {
  finish_test
  return
}

# Setup for logging 
sqlite3_shutdown
test_sqlite3_log [list lappend ::log]
set ::log [list]
sqlite3 db test.db


# With automatic index turned off, we do a full scan of the T2 table
do_test autoindex1-100 {
  db eval {
    CREATE TABLE t1(a,b);
    INSERT INTO t1 VALUES(1,11);
    INSERT INTO t1 VALUES(2,22);

} {11 911 22 922 33 933 44 944 55 955 66 966 77 977 88 988}
do_test autoindex1-111 {
  db status step
} {7}
do_test autoindex1-112 {
  db status autoindex
} {7}
do_test autoindex1-113 {
  set ::log
} {SQLITE_WARNING_AUTOINDEX {automatic index on t2(c)}}

db close
sqlite3_shutdown
test_sqlite3_log
sqlite3_initialize
sqlite3 db test.db

# The same test as above, but this time the T2 query is a subquery rather
# than a join.
do_test autoindex1-200 {
  db eval {
    PRAGMA automatic_index=OFF;
    SELECT b, (SELECT d FROM t2 WHERE c=a) FROM t1;