This presentation explains in details the structure of CUBRID architecture, its components, modules, as well as source code structure. Overall Structure - Query Processing Component - Transaction Management Component - Server Storage Management Component - Client Storage Management Component - Object Management Component - Job and Thread Management Component - Client-Server Communication Layer - Broker Component

1. CUBRID InsideFirst Look Inside CUBRID Jan 18, 2009

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3. CUBRID

4. Contents System Architecture and Processes Design & Implementation Concepts Module and Source Structure In The Next CUBRID Inside 4/ 41 First Look Inside CUBRID

6. System Architecture

7. CUBRID Processes and IPC

8. Query Processing WorkflowSystem Architecture and Processes 1 5/ 41 First Look Inside CUBRID

9. System Architecture and ProcessesWhat is CUBRID? CUBRID is Open Source DBMS owned and developed by NHN Hosted at nForge site Targeted to a database platform for Internet portal service Relational database system with object extensions – Object-Relational Model 1,000,000 line of source code scaled project Engine – C/C++, CUBRID Manager (GUI) and JDBC driver – Java CUBRID provides Full-featured database server engine Server and Broker architecture GUI management and query tool CUBRID Manager Various API (JDBC, ODBC(OLE DB), PHP, and CCI) Python and Ruby as contributed projects 1.1 6/ 41 First Look Inside CUBRID

10. System Architecture and ProcessesSystem Architecture 1.2 Server Subsystem Multi-threaded storage engine part which runs as DB server Consists of Transaction Manager, Object Manager, Lock Manager, Query Manager, Log Manager, and Storage Manager Client Subsystem Client library part providing native C API Consists of Query Parser & Optimizer, Object & Lock Cache, Transaction Manager and Object Manager Broker Subsystem Linked with client library and implemented CCI protocol Does job queuing, connection pooling, monitoring and logging Connectors JDBC driver CCI library Many drivers are implemented with CCI library – ODBC, OLEDB, PHP, Python, and Ruby 7/ 41 First Look Inside CUBRID

11. System Architecture and ProcessesSystem Architecture 1.2 CUBRID Manager GUI Interface PHP OLE DB Ruby CUBRID Manager JDBC ODBC CCI Python CM Server Job Queuing Monitoring Connection Pooling Logging Admin Utility Broker Create, Delete, Copy, Rename Query Parser & Optimizer Lock Cache Object Manager Transaction Manager Add Volume Load / Unload Backup / Restore Query Manager Lock Manager Server Compact / Optimize Storage Manager Log Manager Check / Diag Active Log File Based Objects Data Volume Index Volume Temp Volume Archive Log 8/ 41 First Look Inside CUBRID

12. 1.2 CUBRID Manager GUI Interface PHP OLE DB Ruby CUBRID Manager JDBC ODBC CCI Python CM Server Create, Delete, Copy, Rename Job Queuing Monitoring Connection Pooling Logging Admin Utility Broker Client Library Add Volume Native C API Parser Object Manager Schema Manager Transaction Manager Load / Unload Query Transform Workspace Manager Backup / Restore Query Optimizer Memory Manager Compact / Optimize Plan Generation Check / Diag Communication Module Storage Engine Server Communication Module Transaction Manager Log Manager Lock Manager Query Manager Access Method B+Tree Module File Manager System Catalog Module System Architecture Buffer Manager Disk Manager Active Log File Based Objects Data Volume Index Volume Temp Volume Archive Log 9/ 41 First Look Inside CUBRID

13. System Architecture and ProcessesCUBRID Processes and IPC Master Process ‘cub_master’ Daemon process listening on the TCP port for clients’ connection csql, broker, and admin utilities Registrar of server processes using Unix Domain Socket Server Process ‘cub_server’ Multi-threaded process serving clients’ requests Has thread pool and job queue Accesses database volume and log files One server process per one database Broker Process ‘cub_broker’ Daemon process listening on the TCP port for connectors’ connection Controls cub_cas processes (fork/kill) with connection queue CAS Process ‘cub_cas’ Connects to the server process in behalf of connectors According to the database and user name CSQL Program ‘csql’ Interactive SQL execution 1.3 10/ 41 First Look Inside CUBRID

14. System Architecture and ProcessesCUBRID Processes and IPC 1.3 JDBC driver CCI library connect query & result query & result port listening cub_broker cubrid_broker.conf fork parse descriptor pass AP Web Server cub_cas cub_cas shared memory cubridcs.so cubridcs.so csql connect cubridcs.so request & response request & response parse Broker TCP job queue multi-thread port listening descriptor pass parse cub_master cub_server cubrid.so cubrid.conf UDS Active Server Standby Server mount (read/write) read register volume file log file databases.txt volume file log file Replication cub_admin cubridsa.so 11/ 41 First Look Inside CUBRID

15. System Architecture and ProcessesQuery Processing Workflow 1.4 12/ 41 First Look Inside CUBRID

16. System Architecture and ProcessesQuery Processing Workflow 1.4 XASL Type UNION Extended Access Spec Language (XASL) DIFFERENCE INTERSECTION OBJFETCH Query Manager TransactionManager Lock Manager SETFETCH BUILD_LIST BUILD_VALUE Query Result Cache Query Plan Cache Query Evaluator (Interpreter) SCAN MERGE_LIST Scan Management READ UPDATE Storage Manager DELETE INSERT 13/ 41 First Look Inside CUBRID

18. Object, Class and OID

19. Representation, Record Descriptor, and Memory Object Pointer

20. Workspace – Object & Lock Caching

21. 2PL vs. MVCC

22. XASL (Extended Access Spec Language)

23. Heap, B+tree, Catalog, and Temp

24. Click Counter14/ 41 First Look Inside CUBRID

25. Design & Implementation ConceptsClient-Server and Standalone Mode 2.1 15/ 41 First Look Inside CUBRID

26. Design & Implementation ConceptsObject, Class and OID 2.2 16/ 41 First Look Inside CUBRID

27. Design & Implementation ConceptsRepresentation, Record Descriptor, and Memory Object Pointer 2.3 17/ 41 First Look Inside CUBRID

28. Design & Implementation ConceptsWorkspace – Object & Lock Caching 2.4 18/ 41 First Look Inside CUBRID

29. Design & Implementation Concepts2PL vs. MVCC 2.5 19/ 41 First Look Inside CUBRID

30. Design & Implementation ConceptsXASL (Extended Access Spec Language) 2.6 20/ 41 First Look Inside CUBRID

31. Design & Implementation ConceptsHeap, B+tree, Catalog, and Temp 2.7 21/ 41 First Look Inside CUBRID

32. Design & Implementation ConceptsClick Counter In Terms of User Whenever the user clicks an article, the read counter of the article is increased. Counts the clicks on the article In Terms of Service Application Developer The read counter is very important for bulletin board type service. Combine getting article data and increasing read counter together get_article() + increase_counter() = get_article_and_increase_counter() (SELECT article_info) + (UPDATE read_counter+1) In Terms of Database Engineer Do SELECT and UPDATE in one SQL statement SELECT trigger? SELECT FOR UDPATE? UPDATE the record with the short term lock Example SELECT doc_id, title, INCR(read_counter), post_date FROM board WHERE doc_id=? 2.8 22/ 41 First Look Inside CUBRID

33. Design & Implementation ConceptsClick Counter 2.8 Don’t walk the same passage twice! When you get there, do as many things as possible. Killing two birds with one stone. 23/ 41 First Look Inside CUBRID

35. Query Processing Component

36. Transaction Management Component

37. Server Storage Management Component

38. Client Storage Management Component

39. Object Management Component

40. Job and Thread Management Component

41. Client-Server Communication Layer

42. Broker Component24/ 41 First Look Inside CUBRID

43. Module and Source StructureOverall Structure 41 First Look Inside CUBRID 25/ 3.1 C API Transaction Management Common & Support Broker Job & Thread Management CCI Library Server Storage Management CUBRID Manager Query Processing Client-Server Comm PHP Connector Query Processing Native C API Query Processing Job & Thread Management Utilities Object Management Memory Manager JDBC Driver Client Storage Management Java Stored Procedure

44. 41 First Look Inside CUBRID 26/ Module and Source Structure 3.1 src/ broker CUBRID Manager GUI PHP OLE DB Ruby JDBC ODBC CCI Python CM Server src/ query src/ storage src/ transaction src/ compat Create, Delete, Copy, Rename Job Queuing Monitoring Connection Pooling Logging Client Library Add Volume Native C API Parser Object Manager Schema Manager Transaction Manager Load / Unload Query Transform Workspace Manager Backup / Restore Query Optimizer Memory Manager Compact / Optimize Plan Generation Check / Diag Communication Module src/ cmserver src/ communication src/ jdbc src/ object src/ oledb src/ php src/ cci src/ odbc src/ optimizer src/ base src/ executables src/ heaplayers src/ parser src/ thread src/ connection Storage Engine Communication Module Transaction Manager Log Manager Lock Manager Query Manager Access Method B+Tree Module File Manager System Catalog Module Buffer Manager Disk Manager

45. Module and Source StructureQuery Processing Component Scanner/Parser Parses query string and builds parse tree Uses ANTLR v1.x as parser generator Will be replaced with ‘bison’ at R2.0 Source files in src/parser Data structure: PT_PARSER, PT_NODE, … Semantic Checker Type check and binding, name resolution, semantic checking, view translation, and so on Source files in src/parser Parse tree traversing function: parser_walk_tree() Optimizer Rewrite optimization by heuristic rules Select a query execution plan by CBO (Cost Based Optimization) method Source files in src/parser and src/optimizer Data structure: QO_NODE, QO_PLANNER, … XASL Generator Generate XASL tree from the query execution plan XASL contains scan information (heap/index/list file/set/method scan), value list, and predicates Source files in src/parser Data structure: XASL_NODE, REGU_VARIABLE, … Query Manager (Executor) Executes XASL tree (XASL interpreter) Includes query evaluator, query plan cache, query result cache, query result file, and scan management Source files in src/query Main function: qexec_execute_mainblock() Cursor Manager Extracts tuple from the list file page shipped from the server Query Manager Source files in src/query 3.2 27/ 41 First Look Inside CUBRID

46. Module and Source StructureQuery Processing Component 3.2 Object Management Component Broker Semantic Checker Scanner/Parser Optimizer XASL Generator Cursor Manager Client-Server Communication Layer Client-Server Communication Layer Server Query Plan/Result Cache Query Manager Transaction Management Component Query Evaluator (Interpreter) Storage Management Component (Server) Scan Management 28/ 41 First Look Inside CUBRID

47. Module and Source StructureTransaction Management Component Transaction Manager Controls transaction – start, commit/abort, savepoint, and top operation Works tightly with lock and log manager Supports 2PC protocol for global transaction Initialize other related modules such as lock, log, and recovery manager Source files in src/transaction Data structure: LOG_TDES, TRANTABLE, … Object Locator Controls the flow of objects between the workspaces and the database pages Translates between memory representation and disk representation Caches objects from the server into the workspace with the granted locks Cached object and lock provides fast access to the objects and reduces interacting with the lock manager on the server Source files in src/transaction Lock Manager Based on strict 2PL protocol Includes support for OR feature class lock and instance lock Deadlock detector with WFG As separate thread Source files in src/transaction Data structure: LK_ENTRY, LK_TRAN_LOCK, … Log Manager Transaction logging and recovering REDO/UNDO recovery protocol WAL protocol Physical logging and logical logging Supports group commit and asynchronous commit feature Source files in src/transaciton Data structure: LOG_GLOBAL, LOG_HDRPAGE, LOG_PAGE, 3.3 29/ 41 First Look Inside CUBRID

48. Module and Source StructureTransaction Management Component 3.3 Storage Management Component (Client) Object Management Component Transaction Manager (Client) Broker Object Locator (Client) Client-Server Communication Layer Client-Server Communication Layer Server Object Locator (Server) Lock Manager Transaction Manager (Server) Storage Management Component (Server) Log Manager 30/ 41 First Look Inside CUBRID

49. Module and Source StructureServer Storage Management Component File I/O Manager Provides disk I/O access functions and implements file structure Coordinates the allocation and deallocation of unstructured files and pages File>Sector>Page File manager requests sectors from the disk manager Source files in src/storage Identifier: vdes, PAGEID Disk Manager Volume file management – implements volume structure in a OS file A volume corresponds to a singe file A set of contiguous pages of fixed size Source files in src/storage Identifier: volid Page Buffer Manager Data buffer pool with LRU replacement algorithm Uses buffer hash table and fix/unfix protocol (latch) Source files in src/storage Identifier: VPID Data structure: PGBUF_BUFFER_POOL Slotted Page Manager Manages insertions, deletions, and modifications of records on pages Each record has an associated slot identifier Source files in src/storage OID = (pageid, slotid, volid) Overflow File Manager Larger object than the size of a page is placed on overflow pages Source files in src/storage Object Heap Manager Inserts/deletes/updates objects within a file Permanent unchangeable OID is assigned to an object when it is stored on a heap Provides heap scan method (sequential scan) and direct fetch method An object heap holds the instances of one class Source files in src/storage Identifier: HFID B+-tree Manager Implements prefix B+-tree index with KVL Provides index scan method – unique find and range search 3.4 31/ 41 First Look Inside CUBRID

50. Module and Source StructureServer Storage Management Component 3.4 Broker Client-Server Communication Layer Client-Server Communication Layer Server Query Processing Component (Server) Transaction Management Component (Server) Object Heap Manager B+-tree Manager Large Object Manager Extendible Hash Manager File Manager Slotted Page Manager Overflow File Manager Page Buffer Manager Catalog Manager Disk Manager I/O Manager 32/ 41 First Look Inside CUBRID

51. Module and Source StructureClient Storage Management Component Workspace Manager Maintains a cache of database objects within the virtual memory address space of client process Maintains hash table that maps a OID into MOP MOP has OID field and a pointer to memory object Source files in src/object Quick Fit Allocator Memory manager for workspace Source files in src/object, src/base Garbage Collector To collect and free the unused(dangled) memory objects Normally GC is disabled Object and Lock Caching When the contents of object(s) is(are) required, the object locator is called to fetch the object(s) from the database via the server-side object locator The object locator translate the disk representation of the objet into the memory representation and allocates MOP to points it While accessing the object in the database, the requested lock is held by the lock manager in the server and the memory object has the cached lock mode The cached objects can be decached at any time when its state is not consistent with the disk objects, or will be decached at the time of transaction abort At the time of transaction commit, only the cached locks are released; objects remains with null lock 3.5 33/ 41 First Look Inside CUBRID

52. Module and Source StructureClient Storage Management Component 3.5 Object Management Component Broker Garbage Collector Quick File Allocator Workspace Manager Transaction Management Component Object Locator (Client) Client-Server Communication Layer Client-Server Communication Layer Server 34/ 41 First Look Inside CUBRID

53. Module and Source StructureObject Management Component Object Accessor Interface for object creation, deletion, inspection, and modification Source files in src/object Object Representation Transforms (or translates) between the disk representation and the memory representation of the object Resolves byte ordering also Source files in src/object, src/base Functions: or_xxx(), tf_mem_to_disk(), tf_disk_to_mem(), … Data Type and Domain Internal data structure for data type and domain Source files in src/object Data structure: TP_DOMAIN Sets Source files in src/object Data structure: SETOBJ, COL Schema Manager Implements OR model regarding database schema Definitions of the class object – attributes, method, class inheritance, and conflict resolution Memory representation of class object Source files in src/objet Data structure: SM_CLASS, SM_ATTRIBUTE, … Authentication and Authorization User authentication and database privilege User, GRANT, REVOKE, … Source files in src/object Trigger Manager Implements trigger feature Source files src/object Dynamic Loader Support dynamic loading of shared object as ‘method’ Depreciated feature Large Object Implements glo, elo, fbo classes and supporting methods Source files in src/object 3.6 35/ 41 First Look Inside CUBRID

54. Module and Source StructureObject Management Component 3.6 Object Accessor Broker Schema Manager Authentication & Authorization Trigger Manager Set Dynamic Loader Data Type and Domain Object Representation Storage Management Component (Client) Client-Server Communication Layer Client-Server Communication Layer Server 36/ 41 First Look Inside CUBRID

55. Module and Source StructureJob and Thread Management Component Connection Manager Connection establishment and management and request handler Source files in src/communication, src/connection Data structure: CSS_QUEUE_ENTRY, CSS_CONN_ENTRY, … Job Queue Master thread monitors socket fds (select()), receives clients’ request packet, en-queues it, and then wake up a worker thread in the thread pool Source files in src/connection Data structure: CSS_JOB_ENTRY, … Critical Section Implements semaphore Source files in src/thread System Threads Master thread Deadlock detection thread Run deadlock detection algorithm periodically Resolves deadlock by aborting unilaterally victim transaction(s) Checkpoint thread Executes periodic checkpoint action OOB handling thread Catch OOB signal Page flush thread Flushes dirty data buffer pages to the volume files in the background To reduce burden of page replacement Log flush thread Flushes dirty log buffer pages to the log file in the background Implements group commit and asynchronous commit features Source files in src/thread 3.7 37/ 41 First Look Inside CUBRID

56. Module and Source StructureClient-Server Communication Layer Socket Transceiver Socket utility functions TCP/IP, Unix domain socket, and named pipe Source files in src/connection Linux and Windows port Packet Handler Sends requests and receives response between client and server Packet types: request packet, data packet, close packet, out-of-band packet, error packet, abort packet Packet format: packet header + payload Queuing request and data packets Source files in src/connection Communication Interface Layer RPC stub style functions Implements object serialization Source files in src/communication 3.8 38/ 41 First Look Inside CUBRID

57. Module and Source StructureBroker Component Broker Process Accepts connection requests from the Connectors (JDBC, CCI, …) Allocates and/or assigns CAS process to the request Controls and monitors CAS processes Has four threads main: manages cas process receiver_thread: does accept() and enqueues new job dispatch_thread: dequeue job and assigns cas process cas_monitor_thread: monitors cas process to restart Source files in src/broker CAS Process Linked with CUBRID client library So, run as a single thread Receives and processes requests from the application(Connectors) Connect to database Prepare and execute query Fetch the result Commit/rollback transaction Get/set parameters Has four states IDLE: not connected with AP BUSY: processing request CLIENT_WAIT: connected and waiting for request; within a transaction CLOSE_WAIT: connected and waiting for request; out of a transaction Source files in src/broker 3.9 39/ 41 First Look Inside CUBRID

58. In The Next CUBRID Inside 4 40/ 41 First Look Inside CUBRID

59. In The Next CUBRID Inside 4 What topic do you want to see covered in the next CUBRID Inside? Suggesting Topics 41/ 41 First Look Inside CUBRID

60. Question?