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mirror of https://github.com/mongodb/mongo.git synced 2024-11-30 17:10:48 +01:00
mongodb/db/query.cpp
2009-01-18 20:31:33 -05:00

826 lines
32 KiB
C++

// query.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 "stdafx.h"
#include "query.h"
#include "pdfile.h"
#include "jsobj.h"
#include "../util/builder.h"
#include <time.h>
#include "introspect.h"
#include "btree.h"
#include "../util/lruishmap.h"
#include "javajs.h"
#include "json.h"
#include "repl.h"
#include "replset.h"
#include "scanandorder.h"
#include "security.h"
namespace mongo {
/* We cut off further objects once we cross this threshold; thus, you might get
a little bit more than this, it is a threshold rather than a limit.
*/
const int MaxBytesToReturnToClientAtOnce = 4 * 1024 * 1024;
//ns->query->DiskLoc
LRUishMap<BSONObj,DiskLoc,5> lrutest(123);
int nextCursorId = 1;
extern bool useCursors;
void appendElementHandlingGtLt(BSONObjBuilder& b, BSONElement& e);
int matchDirection( const BSONObj &index, const BSONObj &sort ) {
int direction = 0;
BSONObjIterator i( index );
BSONObjIterator s( sort );
while ( 1 ) {
BSONElement ie = i.next();
BSONElement se = s.next();
if ( ie.eoo() ) {
if ( !se.eoo() )
return 0;
return direction;
}
if ( strcmp( ie.fieldName(), se.fieldName() ) != 0 )
return 0;
int d = ie.number() == se.number() ? 1 : -1;
if ( direction == 0 )
direction = d;
else if ( direction != d )
return 0;
}
}
/* todo: _ use index on partial match with the query
parameters
query - the query, e.g., { name: 'joe' }
order - order by spec, e.g., { name: 1 } 1=ASC, -1=DESC
simpleKeyMatch - set to true if the query is purely for a single key value
unchanged otherwise.
*/
auto_ptr<Cursor> getIndexCursor(const char *ns, BSONObj& query, BSONObj& order, bool *simpleKeyMatch, bool *isSorted, string *hint) {
NamespaceDetails *d = nsdetails(ns);
if ( d == 0 ) return auto_ptr<Cursor>();
if ( hint && !hint->empty() ) {
/* todo: more work needed. doesn't handle $lt & $gt for example.
waiting for query optimizer rewrite (see queryoptimizer.h) before finishing the work.
*/
for (int i = 0; i < d->nIndexes; i++ ) {
IndexDetails& ii = d->indexes[i];
if ( ii.indexName() == *hint ) {
BSONObj startKey = ii.getKeyFromQuery(query);
int direction = 1;
if ( simpleKeyMatch )
*simpleKeyMatch = query.nFields() == startKey.nFields();
if ( isSorted ) *isSorted = false;
return auto_ptr<Cursor>(
new BtreeCursor(ii, startKey, direction, query));
}
}
}
if ( !order.isEmpty() ) {
// order by
for (int i = 0; i < d->nIndexes; i++ ) {
BSONObj idxInfo = d->indexes[i].info.obj(); // { name:, ns:, key: }
assert( strcmp(ns, idxInfo.getStringField("ns")) == 0 );
BSONObj idxKey = idxInfo.getObjectField("key");
int direction = matchDirection( idxKey, order );
if ( direction != 0 ) {
DEV out() << " using index " << d->indexes[i].indexNamespace() << '\n';
if ( isSorted )
*isSorted = true;
return auto_ptr<Cursor>(new BtreeCursor(d->indexes[i], emptyObj, direction, query));
}
}
}
set<string> queryFields;
query.getFieldNames(queryFields);
// regular query without order by
for (int i = 0; i < d->nIndexes; i++ ) {
BSONObj idxInfo = d->indexes[i].info.obj(); // { name:, ns:, key: }
BSONObj idxKey = idxInfo.getObjectField("key");
set<string> keyFields;
idxKey.getFieldNames(keyFields);
if ( keyFields == queryFields ) {
BSONObj q = query.extractFieldsUnDotted(idxKey);
assert(q.objsize() != 0); // guard against a seg fault if details is 0
// Make sure 1st element of index will help us.
BSONElement e = q.firstElement();
/* regexp: only supported if form is /^text/ */
if ( e.type() == RegEx && !e.simpleRegex() )
continue;
if ( e.type() == Object && getGtLtOp( e ) >= JSMatcher::opIN )
continue;
bool simple = true;
BSONObjIterator it( q );
while( simple && it.more() ) {
BSONElement e = it.next();
if ( e.eoo() )
break;
if ( e.type() == RegEx )
simple = false;
if ( e.type() == Object && getGtLtOp( e ) != JSMatcher::Equality )
simple = false;
}
DEV out() << "using index " << d->indexes[i].indexNamespace() << endl;
if ( simple && simpleKeyMatch )
*simpleKeyMatch = true;
return auto_ptr< Cursor >( new BtreeCursor( d->indexes[ i ], emptyObj, 1, query ) );
}
}
DEV out() << "getIndexCursor fail " << ns << '\n';
return auto_ptr<Cursor>();
}
/* ns: namespace, e.g. <database>.<collection>
pattern: the "where" clause / criteria
justOne: stop after 1 match
*/
int deleteObjects(const char *ns, BSONObj pattern, bool justOne, bool god) {
if ( strstr(ns, ".system.") && !god ) {
/* note a delete from system.indexes would corrupt the db
if done here, as there are pointers into those objects in
NamespaceDetails.
*/
if( strstr(ns, ".system.users") )
;
else {
out() << "ERROR: attempt to delete in system namespace " << ns << endl;
return -1;
}
}
int nDeleted = 0;
BSONObj order;
auto_ptr<Cursor> c = getIndexCursor(ns, pattern, order);
if ( c.get() == 0 )
c = theDataFileMgr.findAll(ns);
JSMatcher matcher(pattern, c->indexKeyPattern());
while ( c->ok() ) {
Record *r = c->_current();
DiskLoc rloc = c->currLoc();
BSONObj js(r);
bool deep;
if ( !matcher.matches(js, &deep) ) {
c->advance(); // advance must be after noMoreMatches() because it uses currKey()
}
else {
c->advance(); // must advance before deleting as the next ptr will die
assert( !deep || !c->getsetdup(rloc) ); // can't be a dup, we deleted it!
if ( !justOne )
c->noteLocation();
theDataFileMgr.deleteRecord(ns, r, rloc);
nDeleted++;
if ( justOne )
break;
c->checkLocation();
}
}
return nDeleted;
}
struct Mod {
enum Op { INC, SET } op;
const char *fieldName;
double *ndouble;
int *nint;
void setn(double n) {
if ( ndouble ) *ndouble = n;
else *nint = (int) n;
}
double getn() {
return ndouble ? *ndouble : *nint;
}
int type;
static void getMods(vector<Mod>& mods, BSONObj from);
static void applyMods(vector<Mod>& mods, BSONObj obj);
};
void Mod::applyMods(vector<Mod>& mods, BSONObj obj) {
for ( vector<Mod>::iterator i = mods.begin(); i != mods.end(); i++ ) {
Mod& m = *i;
BSONElement e = obj.findElement(m.fieldName);
if ( e.isNumber() ) {
if ( m.op == INC ) {
e.setNumber( e.number() + m.getn() );
m.setn( e.number() );
// *m.n = e.number() += *m.n;
} else {
e.setNumber( m.getn() ); // $set or $SET
}
}
}
}
/* get special operations like $inc
{ $inc: { a:1, b:1 } }
{ $set: { a:77 } }
NOTE: MODIFIES source from object!
*/
void Mod::getMods(vector<Mod>& mods, BSONObj from) {
BSONObjIterator it(from);
while ( it.more() ) {
BSONElement e = it.next();
const char *fn = e.fieldName();
if ( *fn == '$' && e.type() == Object &&
fn[4] == 0 ) {
BSONObj j = e.embeddedObject();
BSONObjIterator jt(j);
Op op = Mod::SET;
if ( strcmp("$inc",fn) == 0 ) {
op = Mod::INC;
// we rename to $SET instead of $set so that on an op like
// { $set: {x:1}, $inc: {y:1} }
// we don't get two "$set" fields which isn't allowed
strcpy((char *) fn, "$SET");
}
while ( jt.more() ) {
BSONElement f = jt.next();
if ( f.eoo() )
break;
Mod m;
m.op = op;
m.fieldName = f.fieldName();
if ( f.isNumber() ) {
if ( f.type() == NumberDouble ) {
m.ndouble = (double *) f.value();
m.nint = 0;
}
else {
m.ndouble = 0;
m.nint = (int *) f.value();
}
mods.push_back( m );
}
}
}
}
}
/* todo:
_ smart requery find record immediately
returns:
2: we did applyMods() but didn't logOp()
5: we did applyMods() and did logOp() (so don't do it again)
(clean these up later...)
*/
int _updateObjects(const char *ns, BSONObj updateobj, BSONObj pattern, bool upsert, stringstream& ss, bool logop=false) {
int profile = database->profile;
if ( strstr(ns, ".system.") ) {
if( strstr(ns, ".system.users") )
;
else {
out() << "\nERROR: attempt to update in system namespace " << ns << endl;
ss << " can't update system namespace ";
return 0;
}
}
int nscanned = 0;
{
BSONObj order;
auto_ptr<Cursor> c = getIndexCursor(ns, pattern, order);
if ( c.get() == 0 )
c = theDataFileMgr.findAll(ns);
JSMatcher matcher(pattern, c->indexKeyPattern());
while ( c->ok() ) {
Record *r = c->_current();
nscanned++;
BSONObj js(r);
if ( !matcher.matches(js) ) {
}
else {
/* note: we only update one row and quit. if you do multiple later,
be careful or multikeys in arrays could break things badly. best
to only allow updating a single row with a multikey lookup.
*/
if ( profile )
ss << " nscanned:" << nscanned;
/* look for $inc etc. note as listed here, all fields to inc must be this type, you can't set some
regular ones at the moment. */
const char *firstField = updateobj.firstElement().fieldName();
if ( firstField[0] == '$' ) {
vector<Mod> mods;
Mod::getMods(mods, updateobj);
NamespaceDetailsTransient& ndt = NamespaceDetailsTransient::get(ns);
set<string>& idxKeys = ndt.indexKeys();
for ( vector<Mod>::iterator i = mods.begin(); i != mods.end(); i++ ) {
if ( idxKeys.count(i->fieldName) ) {
uassert("can't $inc/$set an indexed field", false);
}
}
Mod::applyMods(mods, c->currLoc().obj());
if ( profile )
ss << " fastmod ";
if ( logop ) {
if ( mods.size() ) {
logOp("u", ns, updateobj, &pattern, &upsert);
return 5;
}
}
return 2;
}
theDataFileMgr.update(ns, r, c->currLoc(), updateobj.objdata(), updateobj.objsize(), ss);
return 1;
}
c->advance();
}
}
if ( profile )
ss << " nscanned:" << nscanned;
if ( upsert ) {
if ( updateobj.firstElement().fieldName()[0] == '$' ) {
/* upsert of an $inc. build a default */
vector<Mod> mods;
Mod::getMods(mods, updateobj);
BSONObjBuilder b;
b.appendElements(pattern);
for ( vector<Mod>::iterator i = mods.begin(); i != mods.end(); i++ )
b.append(i->fieldName, i->getn());
BSONObj obj = b.done();
theDataFileMgr.insert(ns, (void*) obj.objdata(), obj.objsize());
if ( profile )
ss << " fastmodinsert ";
return 3;
}
if ( profile )
ss << " upsert ";
theDataFileMgr.insert(ns, (void*) updateobj.objdata(), updateobj.objsize());
return 4;
}
return 0;
}
/* todo: we can optimize replication by just doing insert when an upsert triggers.
*/
void updateObjects(const char *ns, BSONObj updateobj, BSONObj pattern, bool upsert, stringstream& ss) {
int rc = _updateObjects(ns, updateobj, pattern, upsert, ss, true);
if ( rc != 5 )
logOp("u", ns, updateobj, &pattern, &upsert);
}
int queryTraceLevel = 0;
int otherTraceLevel = 0;
int initialExtentSize(int len);
bool _runCommands(const char *ns, BSONObj& jsobj, stringstream& ss, BufBuilder &b, BSONObjBuilder& anObjBuilder, bool fromRepl);
bool runCommands(const char *ns, BSONObj& jsobj, stringstream& ss, BufBuilder &b, BSONObjBuilder& anObjBuilder, bool fromRepl) {
try {
return _runCommands(ns, jsobj, ss, b, anObjBuilder, fromRepl);
}
catch ( AssertionException e ) {
if ( !e.msg.empty() )
anObjBuilder.append("assertion", e.msg);
}
ss << " assertion ";
anObjBuilder.append("errmsg", "db assertion failure");
anObjBuilder.append("ok", 0.0);
BSONObj x = anObjBuilder.done();
b.append((void*) x.objdata(), x.objsize());
return true;
}
int nCaught = 0;
void killCursors(int n, long long *ids) {
int k = 0;
for ( int i = 0; i < n; i++ ) {
if ( ClientCursor::erase(ids[i]) )
k++;
}
log() << "killCursors: found " << k << " of " << n << '\n';
}
BSONObj id_obj = fromjson("{\"_id\":ObjectId( \"000000000000000000000000\" )}");
BSONObj empty_obj = fromjson("{}");
/* { count: "collectionname"[, query: <query>] }
returns -1 on error.
*/
int runCount(const char *ns, BSONObj& cmd, string& err) {
NamespaceDetails *d = nsdetails(ns);
if ( d == 0 ) {
err = "ns does not exist";
return -1;
}
BSONObj query = cmd.getObjectField("query");
if ( query.isEmpty() ) {
// count of all objects
return (int) d->nrecords;
}
auto_ptr<Cursor> c;
bool simpleKeyToMatch = false;
c = getIndexCursor(ns, query, empty_obj, &simpleKeyToMatch);
if ( c.get() ) {
if ( simpleKeyToMatch ) {
/* Here we only look at the btree keys to determine if a match, instead of looking
into the records, which would be much slower.
*/
int count = 0;
BtreeCursor *bc = dynamic_cast<BtreeCursor *>(c.get());
if ( c->ok() && !query.woCompare( bc->currKeyNode().key, BSONObj(), false ) ) {
BSONObj firstMatch = bc->currKeyNode().key;
count++;
while ( c->advance() ) {
if ( !firstMatch.woEqual( bc->currKeyNode().key ) )
break;
count++;
}
}
return count;
}
} else {
c = findTableScan(ns, empty_obj);
}
int count = 0;
auto_ptr<JSMatcher> matcher(new JSMatcher(query, c->indexKeyPattern()));
while ( c->ok() ) {
BSONObj js = c->current();
bool deep;
if ( !matcher->matches(js, &deep) ) {
}
else if ( !deep || !c->getsetdup(c->currLoc()) ) { // i.e., check for dups on deep items only
// got a match.
count++;
}
c->advance();
}
return count;
}
/* This is for languages whose "objects" are not well ordered (JSON is well ordered).
[ { a : ... } , { b : ... } ] -> { a : ..., b : ... }
*/
inline BSONObj transformOrderFromArrayFormat(BSONObj order) {
/* note: this is slow, but that is ok as order will have very few pieces */
BSONObjBuilder b;
char p[2] = "0";
while ( 1 ) {
BSONObj j = order.getObjectField(p);
if ( j.isEmpty() )
break;
BSONElement e = j.firstElement();
uassert("bad order array", !e.eoo());
uassert("bad order array [2]", e.isNumber());
b.append(e);
(*p)++;
uassert("too many ordering elements", *p <= '9');
}
return b.doneAndDecouple();
}
QueryResult* runQuery(Message& message, const char *ns, int ntoskip, int _ntoreturn, BSONObj jsobj,
auto_ptr< set<string> > filter, stringstream& ss, int queryOptions)
{
Timer t;
int nscanned = 0;
bool wantMore = true;
int ntoreturn = _ntoreturn;
if ( _ntoreturn < 0 ) {
ntoreturn = -_ntoreturn;
wantMore = false;
}
ss << "query " << ns << " ntoreturn:" << ntoreturn;
int n = 0;
BufBuilder b(32768);
BSONObjBuilder cmdResBuf;
long long cursorid = 0;
b.skip(sizeof(QueryResult));
/* we assume you are using findOne() for running a cmd... */
if ( ntoreturn == 1 && runCommands(ns, jsobj, ss, b, cmdResBuf, false) ) {
n = 1;
}
else {
AuthenticationInfo *ai = authInfo.get();
uassert("unauthorized", ai->isAuthorized(database->name.c_str()));
uassert("not master", isMaster() || (queryOptions & Option_SlaveOk));
string hint;
bool explain = false;
bool _gotquery = false;
BSONObj query;// = jsobj.getObjectField("query");
{
BSONElement e = jsobj.findElement("query");
if ( !e.eoo() && (e.type() == Object || e.type() == Array) ) {
query = e.embeddedObject();
_gotquery = true;
}
}
BSONObj order;
{
BSONElement e = jsobj.findElement("orderby");
if ( !e.eoo() ) {
order = e.embeddedObjectUserCheck();
if ( e.type() == Array )
order = transformOrderFromArrayFormat(order);
}
}
if ( !_gotquery && order.isEmpty() )
query = jsobj;
else {
explain = jsobj.getBoolField("$explain");
hint = jsobj.getStringField("$hint");
}
/* The ElemIter will not be happy if this isn't really an object. So throw exception
here when that is true.
(Which may indicate bad data from appserver?)
*/
if ( query.objsize() == 0 ) {
out() << "Bad query object?\n jsobj:";
out() << jsobj.toString() << "\n query:";
out() << query.toString() << endl;
uassert("bad query object", false);
}
bool isSorted = false;
auto_ptr<Cursor> c = getSpecialCursor(ns);
if ( c.get() == 0 )
c = getIndexCursor(ns, query, order, 0, &isSorted, &hint);
if ( c.get() == 0 )
c = findTableScan(ns, order, &isSorted);
auto_ptr<JSMatcher> matcher(new JSMatcher(query, c->indexKeyPattern()));
JSMatcher &debug1 = *matcher;
assert( debug1.getN() < 1000 );
auto_ptr<ScanAndOrder> so;
bool ordering = false;
if ( !order.isEmpty() && !isSorted ) {
ordering = true;
ss << " scanAndOrder ";
so = auto_ptr<ScanAndOrder>(new ScanAndOrder(ntoskip, ntoreturn,order));
wantMore = false;
// scanAndOrder(b, c.get(), order, ntoreturn);
}
while ( c->ok() ) {
BSONObj js = c->current();
//if( queryTraceLevel >= 50 )
// out() << " checking against:\n " << js.toString() << endl;
nscanned++;
bool deep;
if ( !matcher->matches(js, &deep) ) {
}
else if ( !deep || !c->getsetdup(c->currLoc()) ) { // i.e., check for dups on deep items only
// got a match.
assert( js.objsize() >= 0 ); //defensive for segfaults
if ( ordering ) {
// note: no cursors for non-indexed, ordered results. results must be fairly small.
so->add(js);
}
else if ( ntoskip > 0 ) {
ntoskip--;
} else {
if ( explain ) {
n++;
if ( n >= ntoreturn && !wantMore )
break; // .limit() was used, show just that much.
}
else {
bool ok = fillQueryResultFromObj(b, filter.get(), js);
if ( ok ) n++;
if ( ok ) {
if ( (ntoreturn>0 && (n >= ntoreturn || b.len() > MaxBytesToReturnToClientAtOnce)) ||
(ntoreturn==0 && (b.len()>1*1024*1024 || n>=101)) ) {
/* if ntoreturn is zero, we return up to 101 objects. on the subsequent getmore, there
is only a size limit. The idea is that on a find() where one doesn't use much results,
we don't return much, but once getmore kicks in, we start pushing significant quantities.
The n limit (vs. size) is important when someone fetches only one small field from big
objects, which causes massive scanning server-side.
*/
/* if only 1 requested, no cursor saved for efficiency...we assume it is findOne() */
if ( wantMore && ntoreturn != 1 ) {
if ( useCursors ) {
c->advance();
if ( c->ok() ) {
// more...so save a cursor
ClientCursor *cc = new ClientCursor();
cc->c = c;
cursorid = cc->cursorid;
DEV out() << " query has more, cursorid: " << cursorid << endl;
//cc->pattern = query;
cc->matcher = matcher;
cc->ns = ns;
cc->pos = n;
cc->filter = filter;
cc->originalMessage = message;
cc->updateLocation();
}
}
}
break;
}
}
}
}
}
c->advance();
} // end while
if ( explain ) {
BSONObjBuilder builder;
builder.append("cursor", c->toString());
builder.append("startKey", c->prettyStartKey());
builder.append("endKey", c->prettyEndKey());
builder.append("nscanned", nscanned);
builder.append("n", ordering ? so->size() : n);
if ( ordering )
builder.append("scanAndOrder", true);
builder.append("millis", t.millis());
BSONObj obj = builder.done();
fillQueryResultFromObj(b, 0, obj);
n = 1;
} else if ( ordering ) {
so->fill(b, filter.get(), n);
}
else if ( cursorid == 0 && (queryOptions & Option_CursorTailable) && c->tailable() ) {
c->setAtTail();
ClientCursor *cc = new ClientCursor();
cc->c = c;
cursorid = cc->cursorid;
DEV out() << " query has no more but tailable, cursorid: " << cursorid << endl;
//cc->pattern = query;
cc->matcher = matcher;
cc->ns = ns;
cc->pos = n;
cc->filter = filter;
cc->originalMessage = message;
cc->updateLocation();
}
}
QueryResult *qr = (QueryResult *) b.buf();
qr->resultFlags() = 0;
qr->len = b.len();
ss << " reslen:" << b.len();
// qr->channel = 0;
qr->setOperation(opReply);
qr->cursorId = cursorid;
qr->startingFrom = 0;
qr->nReturned = n;
b.decouple();
int duration = t.millis();
if ( (database && database->profile) || duration >= 100 ) {
ss << " nscanned:" << nscanned << ' ';
if ( ntoskip )
ss << " ntoskip:" << ntoskip;
if ( database && database->profile )
ss << " <br>query: ";
ss << jsobj.toString() << ' ';
}
ss << " nreturned:" << n;
return qr;
}
//int dump = 0;
/* empty result for error conditions */
QueryResult* emptyMoreResult(long long cursorid) {
BufBuilder b(32768);
b.skip(sizeof(QueryResult));
QueryResult *qr = (QueryResult *) b.buf();
qr->cursorId = 0; // 0 indicates no more data to retrieve.
qr->startingFrom = 0;
qr->len = b.len();
qr->setOperation(opReply);
qr->nReturned = 0;
b.decouple();
return qr;
}
QueryResult* getMore(const char *ns, int ntoreturn, long long cursorid) {
BufBuilder b(32768);
ClientCursor *cc = ClientCursor::find(cursorid);
b.skip(sizeof(QueryResult));
int resultFlags = 0;
int start = 0;
int n = 0;
if ( !cc ) {
DEV log() << "getMore: cursorid not found " << ns << " " << cursorid << endl;
cursorid = 0;
resultFlags = QueryResult::ResultFlag_CursorNotFound;
}
else {
start = cc->pos;
Cursor *c = cc->c.get();
c->checkLocation();
c->tailResume();
while ( 1 ) {
if ( !c->ok() ) {
if ( c->tailing() ) {
c->setAtTail();
break;
}
DEV log() << " getmore: last batch, erasing cursor " << cursorid << endl;
bool ok = ClientCursor::erase(cursorid);
assert(ok);
cursorid = 0;
cc = 0;
break;
}
BSONObj js = c->current();
bool deep;
if ( !cc->matcher->matches(js, &deep) ) {
}
else {
//out() << "matches " << c->currLoc().toString() << ' ' << deep << '\n';
if ( deep && c->getsetdup(c->currLoc()) ) {
//out() << " but it's a dup \n";
}
else {
bool ok = fillQueryResultFromObj(b, cc->filter.get(), js);
if ( ok ) {
n++;
if ( (ntoreturn>0 && (n >= ntoreturn || b.len() > MaxBytesToReturnToClientAtOnce)) ||
(ntoreturn==0 && b.len()>1*1024*1024) ) {
c->advance();
if ( c->tailing() && !c->ok() )
c->setAtTail();
cc->pos += n;
//cc->updateLocation();
break;
}
}
}
}
c->advance();
}
if ( cc )
cc->updateLocation();
}
QueryResult *qr = (QueryResult *) b.buf();
qr->len = b.len();
qr->setOperation(opReply);
qr->resultFlags() = resultFlags;
qr->cursorId = cursorid;
qr->startingFrom = start;
qr->nReturned = n;
b.decouple();
return qr;
}
} // namespace mongo