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first cut of $hint

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This commit is contained in:
Dwight
2008-11-17 15:39:03 -05:00
parent 3e53cfe1d7
commit 7ce45ce381
6 changed files with 64 additions and 10 deletions
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29
db/query.cpp
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@@ -54,7 +54,7 @@ void appendElementHandlingGtLt(BSONObjBuilder& b, BSONElement& e);
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 = 0, bool *isSorted = 0) {
auto_ptr<Cursor> getIndexCursor(const char *ns, BSONObj& query, BSONObj& order, bool *simpleKeyMatch = 0, bool *isSorted = 0, string *hint = 0) {
NamespaceDetails *d = nsdetails(ns);
if( d == 0 ) return auto_ptr<Cursor>();
@@ -87,6 +87,25 @@ auto_ptr<Cursor> getIndexCursor(const char *ns, BSONObj& query, BSONObj& order,
}
}
if( hint && !hint->empty() ) {
/* todo: more work needed. doesn't handle $lt & $gt for example.
waiting for query optimizer rewrite (see queryoptimizer.h) before finishing the work.
*/
for(int i = 0; i < d->nIndexes; i++ ) {
IndexDetails& ii = d->indexes[i];
if( ii.indexName() == *hint ) {
BSONObj startKey = ii.getKeyFromQuery(query);
int direction = 1;
bool stopMiss = true;
if( simpleKeyMatch )
*simpleKeyMatch = query.nFields() == startKey.nFields();
if( isSorted ) *isSorted = false;
return auto_ptr<Cursor>(
new BtreeCursor(ii, startKey, direction, stopMiss));
}
}
}
// regular query without order by
for(int i = 0; i < d->nIndexes; i++ ) {
BSONObj idxInfo = d->indexes[i].info.obj(); // { name:, ns:, key: }
@@ -104,8 +123,8 @@ auto_ptr<Cursor> getIndexCursor(const char *ns, BSONObj& query, BSONObj& order,
if( match ) {
bool simple = true;
BSONObjBuilder b;
BSONObj q = query.extractFieldsUnDotted(idxKey, b);
//BSONObjBuilder b;
BSONObj q = query.extractFieldsUnDotted(idxKey);
assert(q.objsize() != 0); // guard against a seg fault if details is 0
/* regexp: only supported if form is /^text/ */
BSONObjBuilder b2;
@@ -588,6 +607,7 @@ QueryResult* runQuery(Message& message, const char *ns, int ntoskip, int _ntoret
uassert("not master", isMaster() || (queryOptions & Option_SlaveOk));
string hint;
bool explain = false;
bool _gotquery = false;
BSONObj query;// = jsobj.getObjectField("query");
@@ -611,6 +631,7 @@ QueryResult* runQuery(Message& message, const char *ns, int ntoskip, int _ntoret
query = jsobj;
else {
explain = jsobj.getBoolField("$explain");
hint = jsobj.getStringField("$hint");
}
/* The ElemIter will not be happy if this isn't really an object. So throw exception
@@ -632,7 +653,7 @@ QueryResult* runQuery(Message& message, const char *ns, int ntoskip, int _ntoret
auto_ptr<Cursor> c = getSpecialCursor(ns);
if( c.get() == 0 )
c = getIndexCursor(ns, query, order, 0, &isSorted);
c = getIndexCursor(ns, query, order, 0, &isSorted, &hint);
if( c.get() == 0 )
c = findTableScan(ns, order, &isSorted);