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btree.cpp
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// btree.cpp
/**
* Copyright (C) 2008 10gen Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "pch.h"
#include "db.h"
#include "btree.h"
#include "pdfile.h"
#include "json.h"
#include "clientcursor.h"
#include "client.h"
#include "dbhelpers.h"
#include "curop.h"
#include "stats/counters.h"
namespace mongo {
#define VERIFYTHISLOC dassert( thisLoc.btree() == this );
KeyNode::KeyNode(const BucketBasics& bb, const _KeyNode &k) :
prevChildBucket(k.prevChildBucket),
recordLoc(k.recordLoc), key(bb.data+k.keyDataOfs())
{ }
const int KeyMax = BucketSize / 10;
extern int otherTraceLevel;
const int split_debug = 0;
const int insert_debug = 0;
static void alreadyInIndex() {
// we don't use massert() here as that does logging and this is 'benign' - see catches in _indexRecord()
throw MsgAssertionException(10287, "btree: key+recloc already in index");
}
/* BucketBasics --------------------------------------------------- */
inline void BucketBasics::modified(const DiskLoc& thisLoc) {
VERIFYTHISLOC
btreeStore->modified(thisLoc);
}
int BucketBasics::Size() const {
assert( _wasSize == BucketSize );
return BucketSize;
}
inline void BucketBasics::setNotPacked() {
flags &= ~Packed;
}
inline void BucketBasics::setPacked() {
flags |= Packed;
}
void BucketBasics::_shape(int level, stringstream& ss) {
for ( int i = 0; i < level; i++ ) ss << ' ';
ss << "*\n";
for ( int i = 0; i < n; i++ )
if ( !k(i).prevChildBucket.isNull() )
k(i).prevChildBucket.btree()->_shape(level+1,ss);
if ( !nextChild.isNull() )
nextChild.btree()->_shape(level+1,ss);
}
int bt_fv=0;
int bt_dmp=0;
void BucketBasics::dumpTree(DiskLoc thisLoc, const BSONObj &order) {
bt_dmp=1;
fullValidate(thisLoc, order);
bt_dmp=0;
}
int BucketBasics::fullValidate(const DiskLoc& thisLoc, const BSONObj &order, int *unusedCount) {
{
bool f = false;
assert( f = true );
massert( 10281 , "assert is misdefined", f);
}
killCurrentOp.checkForInterrupt();
assertValid(order, true);
// if( bt_fv==0 )
// return;
if ( bt_dmp ) {
out() << thisLoc.toString() << ' ';
((BtreeBucket *) this)->dump();
}
// keycount
int kc = 0;
for ( int i = 0; i < n; i++ ) {
_KeyNode& kn = k(i);
if ( kn.isUsed() ) {
kc++;
} else {
if ( unusedCount ) {
++( *unusedCount );
}
}
if ( !kn.prevChildBucket.isNull() ) {
DiskLoc left = kn.prevChildBucket;
BtreeBucket *b = left.btree();
wassert( b->parent == thisLoc );
kc += b->fullValidate(kn.prevChildBucket, order, unusedCount);
}
}
if ( !nextChild.isNull() ) {
BtreeBucket *b = nextChild.btree();
wassert( b->parent == thisLoc );
kc += b->fullValidate(nextChild, order, unusedCount);
}
return kc;
}
int nDumped = 0;
void BucketBasics::assertValid(const Ordering &order, bool force) {
if ( !debug && !force )
return;
wassert( n >= 0 && n < Size() );
wassert( emptySize >= 0 && emptySize < BucketSize );
wassert( topSize >= n && topSize <= BucketSize );
DEV {
// slow:
for ( int i = 0; i < n-1; i++ ) {
BSONObj k1 = keyNode(i).key;
BSONObj k2 = keyNode(i+1).key;
int z = k1.woCompare(k2, order); //OK
if ( z > 0 ) {
out() << "ERROR: btree key order corrupt. Keys:" << endl;
if ( ++nDumped < 5 ) {
for ( int j = 0; j < n; j++ ) {
out() << " " << keyNode(j).key.toString() << endl;
}
((BtreeBucket *) this)->dump();
}
wassert(false);
break;
}
else if ( z == 0 ) {
if ( !(k(i).recordLoc < k(i+1).recordLoc) ) {
out() << "ERROR: btree key order corrupt (recordloc's wrong). Keys:" << endl;
out() << " k(" << i << "):" << keyNode(i).key.toString() << " RL:" << k(i).recordLoc.toString() << endl;
out() << " k(" << i+1 << "):" << keyNode(i+1).key.toString() << " RL:" << k(i+1).recordLoc.toString() << endl;
wassert( k(i).recordLoc < k(i+1).recordLoc );
}
}
}
}
else {
//faster:
if ( n > 1 ) {
BSONObj k1 = keyNode(0).key;
BSONObj k2 = keyNode(n-1).key;
int z = k1.woCompare(k2, order);
//wassert( z <= 0 );
if ( z > 0 ) {
problem() << "btree keys out of order" << '\n';
ONCE {
((BtreeBucket *) this)->dump();
}
assert(false);
}
}
}
}
inline void BucketBasics::markUnused(int keypos) {
assert( keypos >= 0 && keypos < n );
k(keypos).setUnused();
}
inline int BucketBasics::totalDataSize() const {
return (int) (Size() - (data-(char*)this));
}
void BucketBasics::init() {
parent.Null();
nextChild.Null();
_wasSize = BucketSize;
_reserved1 = 0;
flags = Packed;
n = 0;
emptySize = totalDataSize();
topSize = 0;
reserved = 0;
}
/* see _alloc */
inline void BucketBasics::_unalloc(int bytes) {
topSize -= bytes;
emptySize += bytes;
}
/* we allocate space from the end of the buffer for data.
the keynodes grow from the front.
*/
inline int BucketBasics::_alloc(int bytes) {
topSize += bytes;
emptySize -= bytes;
int ofs = totalDataSize() - topSize;
assert( ofs > 0 );
return ofs;
}
void BucketBasics::_delKeyAtPos(int keypos) {
assert( keypos >= 0 && keypos <= n );
assert( childForPos(keypos).isNull() );
n--;
assert( n > 0 || nextChild.isNull() );
for ( int j = keypos; j < n; j++ )
k(j) = k(j+1);
emptySize += sizeof(_KeyNode);
setNotPacked();
}
/* pull rightmost key from the bucket. this version requires its right child to be null so it
does not bother returning that value.
*/
void BucketBasics::popBack(DiskLoc& recLoc, BSONObj& key) {
massert( 10282 , "n==0 in btree popBack()", n > 0 );
assert( k(n-1).isUsed() ); // no unused skipping in this function at this point - btreebuilder doesn't require that
KeyNode kn = keyNode(n-1);
recLoc = kn.recordLoc;
key = kn.key;
int keysize = kn.key.objsize();
massert( 10283 , "rchild not null in btree popBack()", nextChild.isNull());
/* weirdly, we also put the rightmost down pointer in nextchild, even when bucket isn't full. */
nextChild = kn.prevChildBucket;
n--;
emptySize += sizeof(_KeyNode);
_unalloc(keysize);
}
/* add a key. must be > all existing. be careful to set next ptr right. */
bool BucketBasics::_pushBack(const DiskLoc& recordLoc, BSONObj& key, const Ordering &order, DiskLoc prevChild) {
int bytesNeeded = key.objsize() + sizeof(_KeyNode);
if ( bytesNeeded > emptySize )
return false;
assert( bytesNeeded <= emptySize );
assert( n == 0 || keyNode(n-1).key.woCompare(key, order) <= 0 );
emptySize -= sizeof(_KeyNode);
_KeyNode& kn = k(n++);
kn.prevChildBucket = prevChild;
kn.recordLoc = recordLoc;
kn.setKeyDataOfs( (short) _alloc(key.objsize()) );
char *p = dataAt(kn.keyDataOfs());
memcpy(p, key.objdata(), key.objsize());
return true;
}
/*void BucketBasics::pushBack(const DiskLoc& recordLoc, BSONObj& key, const BSONObj &order, DiskLoc prevChild, DiskLoc nextChild) {
pushBack(recordLoc, key, order, prevChild);
childForPos(n) = nextChild;
}*/
/* insert a key in a bucket with no complexity -- no splits required */
bool BucketBasics::basicInsert(const DiskLoc& thisLoc, int &keypos, const DiskLoc& recordLoc, const BSONObj& key, const Ordering &order) {
modified(thisLoc);
assert( keypos >= 0 && keypos <= n );
int bytesNeeded = key.objsize() + sizeof(_KeyNode);
if ( bytesNeeded > emptySize ) {
pack( order, keypos );
if ( bytesNeeded > emptySize )
return false;
}
for ( int j = n; j > keypos; j-- ) // make room
k(j) = k(j-1);
n++;
emptySize -= sizeof(_KeyNode);
_KeyNode& kn = k(keypos);
kn.prevChildBucket.Null();
kn.recordLoc = recordLoc;
kn.setKeyDataOfs((short) _alloc(key.objsize()) );
char *p = dataAt(kn.keyDataOfs());
memcpy(p, key.objdata(), key.objsize());
return true;
}
/* when we delete things we just leave empty space until the node is
full and then we repack it.
*/
void BucketBasics::pack( const Ordering &order, int &refPos ) {
if ( flags & Packed )
return;
int tdz = totalDataSize();
char temp[BucketSize];
int ofs = tdz;
topSize = 0;
int i = 0;
for ( int j = 0; j < n; j++ ) {
if( j > 0 && ( j != refPos ) && k( j ).isUnused() && k( j ).prevChildBucket.isNull() ) {
continue; // key is unused and has no children - drop it
}
if( i != j ) {
if ( refPos == j ) {
refPos = i; // i < j so j will never be refPos again
}
k( i ) = k( j );
}
short ofsold = k(i).keyDataOfs();
int sz = keyNode(i).key.objsize();
ofs -= sz;
topSize += sz;
memcpy(temp+ofs, dataAt(ofsold), sz);
k(i).setKeyDataOfsSavingUse( ofs );
++i;
}
if ( refPos == n ) {
refPos = i;
}
n = i;
int dataUsed = tdz - ofs;
memcpy(data + ofs, temp + ofs, dataUsed);
emptySize = tdz - dataUsed - n * sizeof(_KeyNode);
assert( emptySize >= 0 );
setPacked();
assertValid( order );
}
inline void BucketBasics::truncateTo(int N, const Ordering &order, int &refPos) {
n = N;
setNotPacked();
pack( order, refPos );
}
/* - BtreeBucket --------------------------------------------------- */
/* return largest key in the subtree. */
void BtreeBucket::findLargestKey(const DiskLoc& thisLoc, DiskLoc& largestLoc, int& largestKey) {
DiskLoc loc = thisLoc;
while ( 1 ) {
BtreeBucket *b = loc.btree();
if ( !b->nextChild.isNull() ) {
loc = b->nextChild;
continue;
}
assert(b->n>0);
largestLoc = loc;
largestKey = b->n-1;
break;
}
}
int BtreeBucket::customBSONCmp( const BSONObj &l, const BSONObj &rBegin, int rBeginLen, const vector< const BSONElement * > &rEnd, const Ordering &o ) {
BSONObjIterator ll( l );
BSONObjIterator rr( rBegin );
vector< const BSONElement * >::const_iterator rr2 = rEnd.begin();
unsigned mask = 1;
for( int i = 0; i < rBeginLen; ++i, mask <<= 1 ) {
BSONElement lll = ll.next();
BSONElement rrr = rr.next();
++rr2;
int x = lll.woCompare( rrr, false );
if ( o.descending( mask ) )
x = -x;
if ( x != 0 )
return x;
}
for( ; ll.more(); mask <<= 1 ) {
BSONElement lll = ll.next();
BSONElement rrr = **rr2;
++rr2;
int x = lll.woCompare( rrr, false );
if ( o.descending( mask ) )
x = -x;
if ( x != 0 )
return x;
}
return 0;
}
bool BtreeBucket::exists(const IndexDetails& idx, DiskLoc thisLoc, const BSONObj& key, const Ordering& order) {
int pos;
bool found;
DiskLoc b = locate(idx, thisLoc, key, order, pos, found, minDiskLoc);
// skip unused keys
while ( 1 ) {
if( b.isNull() )
break;
BtreeBucket *bucket = b.btree();
_KeyNode& kn = bucket->k(pos);
if ( kn.isUsed() )
return bucket->keyAt(pos).woEqual(key);
b = bucket->advance(b, pos, 1, "BtreeBucket::exists");
}
return false;
}
/* @param self - don't complain about ourself already being in the index case.
@return true = there is a duplicate.
*/
bool BtreeBucket::wouldCreateDup(
const IndexDetails& idx, DiskLoc thisLoc,
const BSONObj& key, const Ordering& order,
DiskLoc self)
{
int pos;
bool found;
DiskLoc b = locate(idx, thisLoc, key, order, pos, found, minDiskLoc);
while ( !b.isNull() ) {
// we skip unused keys
BtreeBucket *bucket = b.btree();
_KeyNode& kn = bucket->k(pos);
if ( kn.isUsed() ) {
if( bucket->keyAt(pos).woEqual(key) )
return kn.recordLoc != self;
break;
}
b = bucket->advance(b, pos, 1, "BtreeBucket::dupCheck");
}
return false;
}
string BtreeBucket::dupKeyError( const IndexDetails& idx , const BSONObj& key ){
stringstream ss;
ss << "E11000 duplicate key error ";
ss << "index: " << idx.indexNamespace() << " ";
ss << "dup key: " << key;
return ss.str();
}
/* Find a key withing this btree bucket.
When duplicate keys are allowed, we use the DiskLoc of the record as if it were part of the
key. That assures that even when there are many duplicates (e.g., 1 million) for a key,
our performance is still good.
assertIfDup: if the key exists (ignoring the recordLoc), uassert
pos: for existing keys k0...kn-1.
returns # it goes BEFORE. so key[pos-1] < key < key[pos]
returns n if it goes after the last existing key.
note result might be an Unused location!
*/
char foo;
bool BtreeBucket::find(const IndexDetails& idx, const BSONObj& key, DiskLoc recordLoc, const Ordering &order, int& pos, bool assertIfDup) {
#if defined(_EXPERIMENT1)
{
char *z = (char *) this;
int i = 0;
while( 1 ) {
i += 4096;
if( i >= BucketSize )
break;
foo += z[i];
}
}
#endif
globalIndexCounters.btree( (char*)this );
/* binary search for this key */
bool dupsChecked = false;
int l=0;
int h=n-1;
while ( l <= h ) {
int m = (l+h)/2;
KeyNode M = keyNode(m);
int x = key.woCompare(M.key, order);
if ( x == 0 ) {
if( assertIfDup ) {
if( k(m).isUnused() ) {
// ok that key is there if unused. but we need to check that there aren't other
// entries for the key then. as it is very rare that we get here, we don't put any
// coding effort in here to make this particularly fast
if( !dupsChecked ) {
dupsChecked = true;
if( idx.head.btree()->exists(idx, idx.head, key, order) ) {
if( idx.head.btree()->wouldCreateDup(idx, idx.head, key, order, recordLoc) )
uasserted( ASSERT_ID_DUPKEY , dupKeyError( idx , key ) );
else
alreadyInIndex();
}
}
}
else {
if( M.recordLoc == recordLoc )
alreadyInIndex();
uasserted( ASSERT_ID_DUPKEY , dupKeyError( idx , key ) );
}
}
// dup keys allowed. use recordLoc as if it is part of the key
DiskLoc unusedRL = M.recordLoc;
unusedRL.GETOFS() &= ~1; // so we can test equality without the used bit messing us up
x = recordLoc.compare(unusedRL);
}
if ( x < 0 ) // key < M.key
h = m-1;
else if ( x > 0 )
l = m+1;
else {
// found it.
pos = m;
return true;
}
}
// not found
pos = l;
if ( pos != n ) {
BSONObj keyatpos = keyNode(pos).key;
wassert( key.woCompare(keyatpos, order) <= 0 );
if ( pos > 0 ) {
wassert( keyNode(pos-1).key.woCompare(key, order) <= 0 );
}
}
return false;
}
void BtreeBucket::delBucket(const DiskLoc& thisLoc, IndexDetails& id) {
ClientCursor::informAboutToDeleteBucket(thisLoc); // slow...
assert( !isHead() );
BtreeBucket *p = parent.btreemod();
if ( p->nextChild == thisLoc ) {
p->nextChild.Null();
}
else {
for ( int i = 0; i < p->n; i++ ) {
if ( p->k(i).prevChildBucket == thisLoc ) {
p->k(i).prevChildBucket.Null();
goto found;
}
}
out() << "ERROR: can't find ref to deleted bucket.\n";
out() << "To delete:\n";
dump();
out() << "Parent:\n";
p->dump();
assert(false);
}
found:
deallocBucket( thisLoc, id );
}
void BtreeBucket::deallocBucket(const DiskLoc &thisLoc, IndexDetails &id) {
#if 0
/* as a temporary defensive measure, we zap the whole bucket, AND don't truly delete
it (meaning it is ineligible for reuse).
*/
memset(this, 0, Size());
modified(thisLoc);
#else
//defensive:
n = -1;
parent.Null();
string ns = id.indexNamespace();
btreeStore->deleteRecord(ns.c_str(), thisLoc);
#endif
}
/* note: may delete the entire bucket! this invalid upon return sometimes. */
void BtreeBucket::delKeyAtPos(const DiskLoc& thisLoc, IndexDetails& id, int p) {
modified(thisLoc);
assert(n>0);
DiskLoc left = childForPos(p);
if ( n == 1 ) {
if ( left.isNull() && nextChild.isNull() ) {
if ( isHead() )
_delKeyAtPos(p); // we don't delete the top bucket ever
else
delBucket(thisLoc, id);
return;
}
markUnused(p);
return;
}
if ( left.isNull() )
_delKeyAtPos(p);
else
markUnused(p);
}
int qqq = 0;
/* remove a key from the index */
bool BtreeBucket::unindex(const DiskLoc& thisLoc, IndexDetails& id, BSONObj& key, const DiskLoc& recordLoc ) {
if ( key.objsize() > KeyMax ) {
OCCASIONALLY problem() << "unindex: key too large to index, skipping " << id.indexNamespace() << /* ' ' << key.toString() << */ endl;
return false;
}
int pos;
bool found;
DiskLoc loc = locate(id, thisLoc, key, Ordering::make(id.keyPattern()), pos, found, recordLoc, 1);
if ( found ) {
loc.btree()->delKeyAtPos(loc, id, pos);
return true;
}
return false;
}
BtreeBucket* BtreeBucket::allocTemp() {
BtreeBucket *b = (BtreeBucket*) malloc(BucketSize);
b->init();
return b;
}
inline void fix(const DiskLoc& thisLoc, const DiskLoc& child) {
if ( !child.isNull() ) {
if ( insert_debug )
out() << " " << child.toString() << ".parent=" << thisLoc.toString() << endl;
child.btreemod()->parent = thisLoc;
}
}
/* this sucks. maybe get rid of parent ptrs. */
void BtreeBucket::fixParentPtrs(const DiskLoc& thisLoc) {
VERIFYTHISLOC
fix(thisLoc, nextChild);
for ( int i = 0; i < n; i++ )
fix(thisLoc, k(i).prevChildBucket);
}
/* insert a key in this bucket, splitting if necessary.
keypos - where to insert the key i3n range 0..n. 0=make leftmost, n=make rightmost.
NOTE this function may free some data, and as a result the value passed for keypos may
be invalid after calling insertHere()
*/
void BtreeBucket::insertHere(DiskLoc thisLoc, int keypos,
DiskLoc recordLoc, const BSONObj& key, const Ordering& order,
DiskLoc lchild, DiskLoc rchild, IndexDetails& idx)
{
modified(thisLoc);
if ( insert_debug )
out() << " " << thisLoc.toString() << ".insertHere " << key.toString() << '/' << recordLoc.toString() << ' '
<< lchild.toString() << ' ' << rchild.toString() << " keypos:" << keypos << endl;
DiskLoc oldLoc = thisLoc;
if ( basicInsert(thisLoc, keypos, recordLoc, key, order) ) {
_KeyNode& kn = k(keypos);
if ( keypos+1 == n ) { // last key
if ( nextChild != lchild ) {
out() << "ERROR nextChild != lchild" << endl;
out() << " thisLoc: " << thisLoc.toString() << ' ' << idx.indexNamespace() << endl;
out() << " keyPos: " << keypos << " n:" << n << endl;
out() << " nextChild: " << nextChild.toString() << " lchild: " << lchild.toString() << endl;
out() << " recordLoc: " << recordLoc.toString() << " rchild: " << rchild.toString() << endl;
out() << " key: " << key.toString() << endl;
dump();
#if 0
out() << "\n\nDUMPING FULL INDEX" << endl;
bt_dmp=1;
bt_fv=1;
idx.head.btree()->fullValidate(idx.head);
#endif
assert(false);
}
kn.prevChildBucket = nextChild;
assert( kn.prevChildBucket == lchild );
nextChild = rchild;
if ( !rchild.isNull() )
rchild.btreemod()->parent = thisLoc;
}
else {
k(keypos).prevChildBucket = lchild;
if ( k(keypos+1).prevChildBucket != lchild ) {
out() << "ERROR k(keypos+1).prevChildBucket != lchild" << endl;
out() << " thisLoc: " << thisLoc.toString() << ' ' << idx.indexNamespace() << endl;
out() << " keyPos: " << keypos << " n:" << n << endl;
out() << " k(keypos+1).pcb: " << k(keypos+1).prevChildBucket.toString() << " lchild: " << lchild.toString() << endl;
out() << " recordLoc: " << recordLoc.toString() << " rchild: " << rchild.toString() << endl;
out() << " key: " << key.toString() << endl;
dump();
#if 0
out() << "\n\nDUMPING FULL INDEX" << endl;
bt_dmp=1;
bt_fv=1;
idx.head.btree()->fullValidate(idx.head);
#endif
assert(false);
}
k(keypos+1).prevChildBucket = rchild;
if ( !rchild.isNull() )
rchild.btreemod()->parent = thisLoc;
}
return;
}
/* ---------- split ---------------- */
if ( split_debug )
out() << " " << thisLoc.toString() << ".split" << endl;
int split = n / 2;
if ( keypos == n ) { // see SERVER-983
split = (int) (0.9 * n);
if ( split > n - 2 )
split = n - 2;
}
DiskLoc rLoc = addBucket(idx);
BtreeBucket *r = rLoc.btreemod();
if ( split_debug )
out() << " split:" << split << ' ' << keyNode(split).key.toString() << " n:" << n << endl;
for ( int i = split+1; i < n; i++ ) {
KeyNode kn = keyNode(i);
r->pushBack(kn.recordLoc, kn.key, order, kn.prevChildBucket);
}
r->nextChild = nextChild;
r->assertValid( order );
if ( split_debug )
out() << " new rLoc:" << rLoc.toString() << endl;
r = 0;
rLoc.btree()->fixParentPtrs(rLoc);
{
KeyNode splitkey = keyNode(split);
nextChild = splitkey.prevChildBucket; // splitkey key gets promoted, its children will be thisLoc (l) and rLoc (r)
if ( split_debug ) {
out() << " splitkey key:" << splitkey.key.toString() << endl;
}
// promote splitkey to a parent node
if ( parent.isNull() ) {
// make a new parent if we were the root
DiskLoc L = addBucket(idx);
BtreeBucket *p = L.btreemod();
p->pushBack(splitkey.recordLoc, splitkey.key, order, thisLoc);
p->nextChild = rLoc;
p->assertValid( order );
parent = idx.head = L;
if ( split_debug )
out() << " we were root, making new root:" << hex << parent.getOfs() << dec << endl;
rLoc.btreemod()->parent = parent;
}
else {
/* set this before calling _insert - if it splits it will do fixParent() logic and change the value.
*/
rLoc.btreemod()->parent = parent;
if ( split_debug )
out() << " promoting splitkey key " << splitkey.key.toString() << endl;
parent.btree()->_insert(parent, splitkey.recordLoc, splitkey.key, order, /*dupsallowed*/true, thisLoc, rLoc, idx);
}
}
int newpos = keypos;
truncateTo(split, order, newpos); // note this may trash splitkey.key. thus we had to promote it before finishing up here.
// add our new key, there is room now
{
if ( keypos <= split ) {
if ( split_debug )
out() << " keypos<split, insertHere() the new key" << endl;
insertHere(thisLoc, newpos, recordLoc, key, order, lchild, rchild, idx);
} else {
int kp = keypos-split-1;
assert(kp>=0);
rLoc.btree()->insertHere(rLoc, kp, recordLoc, key, order, lchild, rchild, idx);
}
}
if ( split_debug )
out() << " split end " << hex << thisLoc.getOfs() << dec << endl;
}
/* start a new index off, empty */
DiskLoc BtreeBucket::addBucket(IndexDetails& id) {
DiskLoc loc = btreeStore->insert(id.indexNamespace().c_str(), 0, BucketSize, true);
BtreeBucket *b = loc.btreemod();
b->init();
return loc;
}
void BtreeBucket::renameIndexNamespace(const char *oldNs, const char *newNs) {
btreeStore->rename( oldNs, newNs );
}
DiskLoc BtreeBucket::getHead(const DiskLoc& thisLoc) {
DiskLoc p = thisLoc;
while ( !p.btree()->isHead() )
p = p.btree()->parent;
return p;
}
DiskLoc BtreeBucket::advance(const DiskLoc& thisLoc, int& keyOfs, int direction, const char *caller) {
if ( keyOfs < 0 || keyOfs >= n ) {
out() << "ASSERT failure BtreeBucket::advance, caller: " << caller << endl;
out() << " thisLoc: " << thisLoc.toString() << endl;
out() << " keyOfs: " << keyOfs << " n:" << n << " direction: " << direction << endl;
out() << bucketSummary() << endl;
assert(false);
}
int adj = direction < 0 ? 1 : 0;
int ko = keyOfs + direction;
DiskLoc nextDown = childForPos(ko+adj);
if ( !nextDown.isNull() ) {
while ( 1 ) {
keyOfs = direction>0 ? 0 : nextDown.btree()->n - 1;
DiskLoc loc = nextDown.btree()->childForPos(keyOfs + adj);
if ( loc.isNull() )
break;
nextDown = loc;
}
return nextDown;
}
if ( ko < n && ko >= 0 ) {
keyOfs = ko;
return thisLoc;
}
// end of bucket. traverse back up.
DiskLoc childLoc = thisLoc;
DiskLoc ancestor = parent;
while ( 1 ) {
if ( ancestor.isNull() )
break;
BtreeBucket *an = ancestor.btree();
for ( int i = 0; i < an->n; i++ ) {
if ( an->childForPos(i+adj) == childLoc ) {
keyOfs = i;
return ancestor;
}
}
assert( direction<0 || an->nextChild == childLoc );
// parent exhausted also, keep going up
childLoc = ancestor;
ancestor = an->parent;
}
return DiskLoc();
}
DiskLoc BtreeBucket::locate(const IndexDetails& idx, const DiskLoc& thisLoc, const BSONObj& key, const Ordering &order, int& pos, bool& found, DiskLoc recordLoc, int direction) {
int p;
found = find(idx, key, recordLoc, order, p, /*assertIfDup*/ false);
if ( found ) {
pos = p;
return thisLoc;
}
DiskLoc child = childForPos(p);
if ( !child.isNull() ) {
DiskLoc l = child.btree()->locate(idx, child, key, order, pos, found, recordLoc, direction);
if ( !l.isNull() )
return l;
}
pos = p;
if ( direction < 0 )
return --pos == -1 ? DiskLoc() /*theend*/ : thisLoc;
else
return pos == n ? DiskLoc() /*theend*/ : thisLoc;
}
bool BtreeBucket::customFind( int l, int h, const BSONObj &keyBegin, int keyBeginLen, const vector< const BSONElement * > &keyEnd, const Ordering &order, int direction, DiskLoc &thisLoc, int &keyOfs, pair< DiskLoc, int > &bestParent ) {
while( 1 ) {
if ( l + 1 == h ) {
keyOfs = ( direction > 0 ) ? h : l;
DiskLoc next = thisLoc.btree()->k( h ).prevChildBucket;
if ( !next.isNull() ) {
bestParent = make_pair( thisLoc, keyOfs );
thisLoc = next;
return true;
} else {
return false;
}
}
int m = l + ( h - l ) / 2;
int cmp = customBSONCmp( thisLoc.btree()->keyNode( m ).key, keyBegin, keyBeginLen, keyEnd, order );
if ( cmp < 0 ) {
l = m;
} else if ( cmp > 0 ) {
h = m;
} else {
if ( direction < 0 ) {
l = m;
} else {
h = m;
}
}
}
}
// find smallest/biggest value greater-equal/less-equal than specified
// starting thisLoc + keyOfs will be strictly less than/strictly greater than keyBegin/keyBeginLen/keyEnd
// All the direction checks below allowed me to refactor the code, but possibly separate forward and reverse implementations would be more efficient
void BtreeBucket::advanceTo(const IndexDetails &id, DiskLoc &thisLoc, int &keyOfs, const BSONObj &keyBegin, int keyBeginLen, const vector< const BSONElement * > &keyEnd, const Ordering &order, int direction ) {
int l,h;
bool dontGoUp;
if ( direction > 0 ) {
l = keyOfs;
h = n - 1;
dontGoUp = ( customBSONCmp( keyNode( h ).key, keyBegin, keyBeginLen, keyEnd, order ) >= 0 );
} else {
l = 0;
h = keyOfs;
dontGoUp = ( customBSONCmp( keyNode( l ).key, keyBegin, keyBeginLen, keyEnd, order ) <= 0 );
}
pair< DiskLoc, int > bestParent;
if ( dontGoUp ) {
// this comparison result assures h > l
if ( !customFind( l, h, keyBegin, keyBeginLen, keyEnd, order, direction, thisLoc, keyOfs, bestParent ) ) {
return;
}
} else {
// go up parents until rightmost/leftmost node is >=/<= target or at top
while( !thisLoc.btree()->parent.isNull() ) {
thisLoc = thisLoc.btree()->parent;
if ( direction > 0 ) {
if ( customBSONCmp( thisLoc.btree()->keyNode( thisLoc.btree()->n - 1 ).key, keyBegin, keyBeginLen, keyEnd, order ) >= 0 ) {
break;
}
} else {
if ( customBSONCmp( thisLoc.btree()->keyNode( 0 ).key, keyBegin, keyBeginLen, keyEnd, order ) <= 0 ) {
break;
}
}
}
}
// go down until find smallest/biggest >=/<= target
while( 1 ) {
l = 0;
h = thisLoc.btree()->n - 1;
// leftmost/rightmost key may possibly be >=/<= search key
bool firstCheck;
if ( direction > 0 ) {
firstCheck = ( customBSONCmp( thisLoc.btree()->keyNode( 0 ).key, keyBegin, keyBeginLen, keyEnd, order ) >= 0 );
} else {
firstCheck = ( customBSONCmp( thisLoc.btree()->keyNode( h ).key, keyBegin, keyBeginLen, keyEnd, order ) <= 0 );
}
if ( firstCheck ) {
DiskLoc next;
if ( direction > 0 ) {
next = thisLoc.btree()->k( 0 ).prevChildBucket;
keyOfs = 0;
} else {
next = thisLoc.btree()->nextChild;
keyOfs = h;
}
if ( !next.isNull() ) {
bestParent = make_pair( thisLoc, keyOfs );
thisLoc = next;
continue;
} else {
return;
}
}
bool secondCheck;
if ( direction > 0 ) {
secondCheck = ( customBSONCmp( thisLoc.btree()->keyNode( h ).key, keyBegin, keyBeginLen, keyEnd, order ) < 0 );
} else {
secondCheck = ( customBSONCmp( thisLoc.btree()->keyNode( 0 ).key, keyBegin, keyBeginLen, keyEnd, order ) > 0 );
}
if ( secondCheck ) {
DiskLoc next;
if ( direction > 0 ) {
next = thisLoc.btree()->nextChild;
} else {
next = thisLoc.btree()->k( 0 ).prevChildBucket;
}
if ( next.isNull() ) {
// if bestParent is null, we've hit the end and thisLoc gets set to DiskLoc()
thisLoc = bestParent.first;
keyOfs = bestParent.second;
return;
} else {
thisLoc = next;
continue;
}
}
if ( !customFind( l, h, keyBegin, keyBeginLen, keyEnd, order, direction, thisLoc, keyOfs, bestParent ) ) {
return;