void BtreeCursor::skipAndCheck() {
long long startNscanned = _nscanned;
skipUnusedKeys();
while( 1 ) {
if ( !skipOutOfRangeKeysAndCheckEnd() ) {
break;
}
do {
// If nscanned is increased by more than 20 before a matching key is found, abort
// skipping through the btree to find a matching key. This iteration cutoff
// prevents unbounded internal iteration within BtreeCursor::init() and
// BtreeCursor::advance() (the callers of skipAndCheck()). See SERVER-3448.
if ( _nscanned > startNscanned + 20 ) {
skipUnusedKeys();
// If iteration is aborted before a key matching _bounds is identified, the
// cursor may be left pointing at a key that is not within bounds
// (_bounds->matchesKey( currKey() ) may be false). Set _boundsMustMatch to
// false accordingly.
_boundsMustMatch = false;
return;
}
} while( skipOutOfRangeKeysAndCheckEnd() );
if ( !skipUnusedKeys() ) {
break;
}
}
}
// Check the current key with respect to our key bounds, whether
// it be provided by independent field ranges or by start/end keys.
bool IndexCursor::checkCurrentAgainstBounds() {
if ( _bounds == NULL ) {
checkEnd();
if ( ok() ) {
++_nscanned;
}
} else {
// If nscanned is increased by more than 20 before a matching key is found, abort
// skipping through the index to find a matching key. This iteration cutoff
// prevents unbounded internal iteration within IndexCursor::initializeDBC and
// IndexCursor::advance(). See SERVER-3448.
const long long startNscanned = _nscanned;
if ( skipOutOfRangeKeysAndCheckEnd() ) {
do {
if ( _nscanned > startNscanned + 20 ) {
// If iteration is aborted before a key matching _bounds is identified, the
// cursor may be left pointing at a key that is not within bounds
// (_bounds->matchesKey( currKey() ) may be false). Set _boundsMustMatch to
// false accordingly.
_boundsMustMatch = false;
break;
}
} while ( skipOutOfRangeKeysAndCheckEnd() );
}
}
return ok();
}
void BtreeCursor::skipAndCheck() {
skipUnusedKeys( true );
while( 1 ) {
if ( !skipOutOfRangeKeysAndCheckEnd() ) {
break;
}
while( skipOutOfRangeKeysAndCheckEnd() );
if ( !skipUnusedKeys( true ) ) {
break;
}
}
}
void BtreeCursor::skipAndCheck() {
long long startNscanned = _nscanned;
skipUnusedKeys();
while( 1 ) {
if ( !skipOutOfRangeKeysAndCheckEnd() ) {
break;
}
do {
if ( _nscanned > startNscanned + 20 ) {
skipUnusedKeys();
return;
}
} while( skipOutOfRangeKeysAndCheckEnd() );
if ( !skipUnusedKeys() ) {
break;
}
}
}
/* skip unused keys. */
bool BtreeCursor::skipUnusedKeys( bool mayJump ) {
int u = 0;
while ( 1 ) {
if ( !ok() )
break;
BtreeBucket *b = bucket.btree();
_KeyNode& kn = b->k(keyOfs);
if ( kn.isUsed() )
break;
bucket = b->advance(bucket, keyOfs, direction, "skipUnusedKeys");
u++;
if ( mayJump && ( u % 10 == 0 ) ) {
skipOutOfRangeKeysAndCheckEnd();
}
}
if ( u > 10 )
OCCASIONALLY log() << "btree unused skipped:" << u << '\n';
return u;
}
/* skip unused keys. */
bool BtreeCursor::skipUnusedKeys( bool mayJump ) {
int u = 0;
while ( 1 ) {
if ( !ok() )
break;
const _KeyNode& kn = keyNode(keyOfs);
if ( kn.isUsed() )
break;
bucket = _advance(bucket, keyOfs, _direction, "skipUnusedKeys");
u++;
//don't include unused keys in nscanned
//++_nscanned;
if ( mayJump && ( u % 10 == 0 ) ) {
skipOutOfRangeKeysAndCheckEnd();
}
}
if ( u > 10 )
OCCASIONALLY log() << "btree unused skipped:" << u << '\n';
return u;
}
