/**
* Returns true if request is a query for sharded indexes.
*/
static bool doShardedIndexQuery(OperationContext* txn, Request& r, const QuerySpec& qSpec) {
// Extract the ns field from the query, which may be embedded within the "query" or
// "$query" field.
auto nsField = qSpec.filter()["ns"];
if (nsField.eoo()) {
return false;
}
const NamespaceString indexNSSQuery(nsField.str());
auto status = grid.catalogCache()->getDatabase(txn, indexNSSQuery.db().toString());
if (!status.isOK()) {
return false;
}
shared_ptr<DBConfig> config = status.getValue();
if (!config->isSharded(indexNSSQuery.ns())) {
return false;
}
// if you are querying on system.indexes, we need to make sure we go to a shard
// that actually has chunks. This is not a perfect solution (what if you just
// look at all indexes), but better than doing nothing.
ShardPtr shard;
ChunkManagerPtr cm;
config->getChunkManagerOrPrimary(indexNSSQuery.ns(), cm, shard);
if (cm) {
set<ShardId> shardIds;
cm->getAllShardIds(&shardIds);
verify(shardIds.size() > 0);
shard = grid.shardRegistry()->getShard(*shardIds.begin());
}
ShardConnection dbcon(shard->getConnString(), r.getns());
DBClientBase& c = dbcon.conn();
string actualServer;
Message response;
bool ok = c.call(r.m(), response, true, &actualServer);
uassert(10200, "mongos: error calling db", ok);
{
QueryResult::View qr = response.singleData().view2ptr();
if (qr.getResultFlags() & ResultFlag_ShardConfigStale) {
dbcon.done();
// Version is zero b/c this is deprecated codepath
throw RecvStaleConfigException(r.getns(),
"Strategy::doQuery",
ChunkVersion(0, 0, OID()),
ChunkVersion(0, 0, OID()));
}
}
r.reply(response, actualServer.size() ? actualServer : c.getServerAddress());
dbcon.done();
return true;
}
