1. MongoDB
2011/6/28

2. • @nobu_k
• Preferred Infrastructure (PFI)
• Sedue
• Sedue MongoDB(1.6)
• CT○
• http://slidesha.re/hl8PyL
• MongoDB as Search Engine Repository

3. • oplog
•

4. • MongoDB
• https://github.com/mongodb/mongo/
commits/master/
• 2011/6/26
•2
• pull

5. oplog
•

6. • 2
• createOplog
• logOp
• db/oplog[h,cpp]
•

7. createOplog
• oplog
•

8. createOplog
void createOplog() { > use local
dblock lk; // DB switched to db local
> show collections
// DB. me
const char * ns = "local.oplog.$main"; oplog.$main
pair.sync
slaves
sources
system.indexes
bool rs = !cmdLine._replSet.empty();
if( rs )
ns = rsoplog; // "local.oplog.rs";
// in db/repl/rs_optime.h
NS

9. oplog
Client::Context ctx(ns); // NS
NamespaceDetails * nsd = nsdetails( ns );
if ( nsd ) { // oplog
... ...
... ...
}

10. • oplog
• ReplicaSet
•

11. oplog
• oplog
•
1. oplog
2. BSON NS
• BSON!!
3. oplog

12. •
• Mac
• oplog capped collection

13. createOplog
•
• db/repl.cpp
• db/repl/rs_initialsync.cpp
• db/repl/rs_initiate.cpp
• ReplicaSet
•

14. •
• dblock
• CmdLine
• Context
• DBDirectClient
• NamespaceDetails, nsdetails
•

15. dblock
• DB
• db/concurrency.h
• Deprecated
• writelock
• dbMutex
• scoped_lock
• RAII

16. CmdLine
•
• db/cmdline.[h, cpp]
• boost::program_options
• extern 2
• db/db.cpp //
• client/clientOnly.cpp //

17. Client::Context
•
• NS
• Client
• db/client.[h,cpp]
• RAII
• DB

18. currentClient
• Client
• Thread Local
• boost::thread_specific_ptr<Client>
• cc(), currenctClient, Context::getClient
• DB

19. DBDirectClient
•
• DBClientInterface (client/dbclient.h)
• DBConnector (client/dbclient.h)
• DBClientWithCommands : public DBClientInterface
• DBClientBase : public DBClientWithCommands, public DBConnector
• DBDirectClient : public DBClientBase
• findOne
• c.findOne→DBClientInterface::findOne→DBClientInterface::findN→(virtual
)DBDirectClient::query→DBClientBase::query
• DBClientCursor
•

20. NamespaceDetails
• .ns (1 )
•
• Database
• MongoDataFile
• Record
•

21. nsdetails
• Context NamespaceDetails
• db/pdfile.h
• cc().database()->namespaceIndex->details
• NamespaceIndex
• map<string, NamespaceDetails>
•

22. logOp
•
•

23. oplog
{
ts: • oplog BSON
op:
ns: NS •
o: BSON
o2:
} • o2

24. • i : insert
• u : update
• d : delete
• c : db cmd? userCreateNS?
• db : declares presence of a database
• n : no op ( )
•
• keep alive
•

25. logOp
_logOp
void logOp(const char *opstr, const char *ns,
const BSONObj& obj, BSONObj *patt, bool *b) {
if ( replSettings.master ) {
_logOp(opstr, ns, 0, obj, patt, b);
}
logOpForSharding( opstr , ns , obj , patt );
}

26. _logOp
•
• _logOpOld
• _logOpRS
• etc?
•

27. _logOpOld
•
• Record theDataFileMgr
• fast_oplog_insert!!
• ( mmap
)

28. append_O_Obj
• partial ”o”+
• BSONBuilder
•
• repeatedly ed

29. _logOpRS
•

30. logOp
•
• grep it!

31. • applyOperation_inlock
• pretouch

32. We are hiring !
•
•
•
•
•
•
•
• OSS
•
• (´ ω `)