SQLite

** to which the constraint applies. The leftmost coordinate column
** is 'a', the second from the left 'b' etc.
*/
static int rtreeBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
  Rtree *pRtree = (Rtree*)tab;
  int rc = SQLITE_OK;
  int ii;
  int bMatch = 0;                 /* True if there exists a MATCH constraint */
  i64 nRow;                       /* Estimated rows returned by this scan */

  int iIdx = 0;
  char zIdxStr[RTREE_MAX_DIMENSIONS*8+1];
  memset(zIdxStr, 0, sizeof(zIdxStr));

  /* Check if there exists a MATCH constraint - even an unusable one. If there
  ** is, do not consider the lookup-by-rowid plan as using such a plan would
  ** require the VDBE to evaluate the MATCH constraint, which is not currently
  ** possible. */
  for(ii=0; ii<pIdxInfo->nConstraint; ii++){
    if( pIdxInfo->aConstraint[ii].op==SQLITE_INDEX_CONSTRAINT_MATCH ){
      bMatch = 1;
    }
  }

  assert( pIdxInfo->idxStr==0 );
  for(ii=0; ii<pIdxInfo->nConstraint && iIdx<(int)(sizeof(zIdxStr)-1); ii++){
    struct sqlite3_index_constraint *p = &pIdxInfo->aConstraint[ii];

    if( bMatch==0 && p->usable 
    if( p->usable && p->iColumn==0 && p->op==SQLITE_INDEX_CONSTRAINT_EQ ){
     && p->iColumn==0 && p->op==SQLITE_INDEX_CONSTRAINT_EQ 
    ){
      /* We have an equality constraint on the rowid. Use strategy 1. */
      int jj;
      for(jj=0; jj<ii; jj++){
        pIdxInfo->aConstraintUsage[jj].argvIndex = 0;
        pIdxInfo->aConstraintUsage[jj].omit = 0;
      }
      pIdxInfo->idxNum = 1;

  SELECT id FROM rt1 WHERE id MATCH Qcircle('r:1000 e:4') ORDER BY +id
} {0 2 4 6 8 10 12 14 16 18 20 22 24 100 102 104 106 108 110 112 114 116 118 120 122 124 200 202 204 206 208 210 212 214 216 218 220 222 224}

# Exclude odd rowids on a breadth-first search.
do_execsql_test rtreeE-1.6 {
  SELECT id FROM rt1 WHERE id MATCH Qcircle(0,0,1000,5) ORDER BY +id
} {0 2 4 6 8 10 12 14 16 18 20 22 24 100 102 104 106 108 110 112 114 116 118 120 122 124 200 202 204 206 208 210 212 214 216 218 220 222 224}

# Test that rtree prefers MATCH to lookup-by-rowid.
#
do_execsql_test rtreeE-1.7 {
  SELECT id FROM rt1 WHERE id=18 AND id MATCH Qcircle(0,0,1000,5)
} {18}


# Construct a large 2-D RTree with thousands of random entries.
#
do_test rtreeE-2.1 {
  db eval {
    CREATE TABLE t2(id,x0,x1,y0,y1);
    CREATE VIRTUAL TABLE rt2 USING rtree(id,x0,x1,y0,y1);

do_execsql_test rtreeE-2.3 {
  SELECT id FROM rt2 WHERE id MATCH breadthfirstsearch(0,5000,0,5000) ORDER BY id
} $ans
set ans [db eval {SELECT id FROM t2 WHERE x1>=0 AND x0<=10000 AND y1>=0 AND y0<=10000 ORDER BY id}]
do_execsql_test rtreeE-2.4 {
  SELECT id FROM rt2 WHERE id MATCH breadthfirstsearch(0,10000,0,10000) ORDER BY id
} $ans


finish_test