void ChunkManager::getShardIdsForQuery(OperationContext* txn,
const BSONObj& query,
set<ShardId>* shardIds) const {
auto statusWithCQ =
CanonicalQuery::canonicalize(NamespaceString(_ns), query, ExtensionsCallbackNoop());
uassertStatusOK(statusWithCQ.getStatus());
unique_ptr<CanonicalQuery> cq = std::move(statusWithCQ.getValue());
// Query validation
if (QueryPlannerCommon::hasNode(cq->root(), MatchExpression::GEO_NEAR)) {
uassert(13501, "use geoNear command rather than $near query", false);
}
// Fast path for targeting equalities on the shard key.
auto shardKeyToFind = _keyPattern.extractShardKeyFromQuery(*cq);
if (shardKeyToFind.isOK() && !shardKeyToFind.getValue().isEmpty()) {
auto chunk = findIntersectingChunk(txn, shardKeyToFind.getValue());
shardIds->insert(chunk->getShardId());
return;
}
// Transforms query into bounds for each field in the shard key
// for example :
// Key { a: 1, b: 1 },
// Query { a : { $gte : 1, $lt : 2 },
// b : { $gte : 3, $lt : 4 } }
// => Bounds { a : [1, 2), b : [3, 4) }
IndexBounds bounds = getIndexBoundsForQuery(_keyPattern.toBSON(), *cq);
// Transforms bounds for each shard key field into full shard key ranges
// for example :
// Key { a : 1, b : 1 }
// Bounds { a : [1, 2), b : [3, 4) }
// => Ranges { a : 1, b : 3 } => { a : 2, b : 4 }
BoundList ranges = _keyPattern.flattenBounds(bounds);
for (BoundList::const_iterator it = ranges.begin(); it != ranges.end(); ++it) {
getShardIdsForRange(*shardIds, it->first /*min*/, it->second /*max*/);
// once we know we need to visit all shards no need to keep looping
if (shardIds->size() == _shardIds.size())
break;
}
// SERVER-4914 Some clients of getShardIdsForQuery() assume at least one shard will be
// returned. For now, we satisfy that assumption by adding a shard with no matches rather
// than return an empty set of shards.
if (shardIds->empty()) {
massert(16068, "no chunk ranges available", !_chunkRanges.ranges().empty());
shardIds->insert(_chunkRanges.ranges().begin()->second->getShardId());
}
}
void ChunkManager::getShardIdsForQuery(set<ShardId>& shardIds, const BSONObj& query) const {
CanonicalQuery* canonicalQuery = NULL;
Status status = CanonicalQuery::canonicalize(
_ns,
query,
&canonicalQuery,
WhereCallbackNoop());
boost::scoped_ptr<CanonicalQuery> canonicalQueryPtr(canonicalQuery);
uassert(status.code(), status.reason(), status.isOK());
// Query validation
if (QueryPlannerCommon::hasNode(canonicalQuery->root(), MatchExpression::GEO_NEAR)) {
uassert(13501, "use geoNear command rather than $near query", false);
}
// Transforms query into bounds for each field in the shard key
// for example :
// Key { a: 1, b: 1 },
// Query { a : { $gte : 1, $lt : 2 },
// b : { $gte : 3, $lt : 4 } }
// => Bounds { a : [1, 2), b : [3, 4) }
IndexBounds bounds = getIndexBoundsForQuery(_keyPattern.toBSON(), canonicalQuery);
// Transforms bounds for each shard key field into full shard key ranges
// for example :
// Key { a : 1, b : 1 }
// Bounds { a : [1, 2), b : [3, 4) }
// => Ranges { a : 1, b : 3 } => { a : 2, b : 4 }
BoundList ranges = _keyPattern.flattenBounds(bounds);
for (BoundList::const_iterator it = ranges.begin(); it != ranges.end();
++it) {
getShardIdsForRange(shardIds, it->first /*min*/, it->second /*max*/);
// once we know we need to visit all shards no need to keep looping
if(shardIds.size() == _shardIds.size()) break;
}
// SERVER-4914 Some clients of getShardIdsForQuery() assume at least one shard will be
// returned. For now, we satisfy that assumption by adding a shard with no matches rather
// than return an empty set of shards.
if (shardIds.empty()) {
massert( 16068, "no chunk ranges available", !_chunkRanges.ranges().empty() );
shardIds.insert(_chunkRanges.ranges().begin()->second->getShardId());
}
}
