1 Scalable Distributed Database System: SD-SQL Server Soror SAHRI Ceria, Paris-Dauphine University Journées Académiques Microsoft Paris, April 2006

2 Overview Objective SD-SQL Server Architecture Application Interface Implementation Performance Analysis Conclusion

3 Objective Most of DBSs have distributed/parallel versions SQL Server, Oracle, DB2… DBSs do not provide dynamic partitioning of relational tables All require manual (distributed) repartitioning when tables scale-up

4 Objective   Research Report, December 2005  [Oracle Database 10g]

5 Objective  Scalable Distributed Partitioning of Relational Tables  Scalable Distributed Database System (SD-DBS) Litwin, Rich & Schwartz  “Architecture for a scalable Distributed DBSs”  2nd Intl. Workshop on Cooperative Internet Computing, 2002

6 SD-SQL Server SD-SQL Server is the first prototype SD-DBS Generalizes SQL Server Shared Nothing Architecture Embeds SQL Server 2000 (at present) Up to 250 nodes (at present)

7 SD-SQL Server Architecture Linked SQL Servers D1 D2DiDi+1 SSPC D1_T _D1_T User/Application T sd_create_table User/Application sd_insert _D1_T Split NDBs SD-SQL server SD-SQL client SD-SQL Server Managers SD-SQL peer

8 Nodes, NDBs and SDBs DB1 SDB Node1Node2Node3Nodei DB1DB1 …… DB1 DB1DB1 DB2 SDB DB2 MDB

9 NDB Types An SD-SQL Server NDB can be: Client NDB Carries only images Application interfaces Server NDB Carries only the segments Peer NDB Both functions Primary NDB First created for an SDB

10 Scalable Tables A scalable (distributed) table is a collection of segments Segments are SQL tables A scalable table has, initially, only one primary segment At some server or peer NDB The number of segments in a scalable table is variable Overflowing segments split

11 Splitting A split occurs when an insert overflows the segment capacity Splits produce other segments for a scalable table. Each is located at a different NDB Within the SDB If there is not enough NDBs, splits dynamically append new ones

12 SDB DB1 Splitting Scalable Table T sd_insert N1N2N4N3 NDB DB1 sd_insert NDB DB1 Ni sd_create_node sd_insert N3 NDB DB1 sd_create_node_database NDB DB1 ……. sd_create_node_database

13 Splitting S b+1 S S1S1 p b+1-p p=INT(b/2) C( S)=   { c: c < h = c (b+1-p)} C( S 1 )={c: c > = c (b+1-p)} Check Constraint? b SELECT TOP Pi * INTO Ni.Si FROM S ORDER BY C ASC SELECT TOP Pi * WITH TIES INTO Ni.S1 FROM S ORDER BY C ASC

14 Images Images hide the scalable table segments An image is a distributed updateable partitioned view of a scalable table Union-all view with check constraints An image presents the scalable table partitioning It do not address any new segments resulted from a split

15 Images Primary image Resides at the creation node Has the name of the scalable table Secondary images Reside at other client or peer NDBs of the SDB Have a specific name, other than that of the table  To avoid name conflict Scalable Views Carry images at several levels

16 Images DB1 SDB N1.DB1 N2.DB1 N3.DB1 T Scalable Table Primary Image CREATE VIEW T AS SELECT * FROM N1.DB1._Ni_T UNION ALL SELECT * FROM N2.DB1._Ni_T UNION ALL SELECT * FROM N3.DB1._Ni_T

17 Application Interface Applications manipulate SD-SQL Server through its command interface. SD-SQL Server commands start with ‘sd_’ To distinguish from SQL Server commands for static tables. INSERT sd_insert CREATE TABLE sd_create_table

18 Application Interface: The SkyServer Benchmark Use of the SkyServer DB as benchmark Use of the PhotoObj table as a scalable table. PhotoObj has 158,426 tuples (about 260 MB)

19 Application Interface: Node Management Node Creation sd_create_node ‘Dell1’ /* Server by default */ sd_create_node ‘Ceria’, ‘client’ Node Alteration sd_alter_node ‘Ceria’, ‘ADD server’ /* Becomes peer*/ Node Removal sd_drop_node ‘Ceria’

20 Application Interface: NDBs &SDBs Management SDB Creation sd_create_scalable_database ‘SkyServer’, ‘Dell1’, ‘Server’, 2 /* Creates the primary SkyServer NDB as well at Dell1*/ NDB Creation sd_create_node_database ‘SkyServer’, ‘Ceria’, ‘Client’ SDB Removal sd_drop_scalable_database ‘SkyServer’

21 Application Interface: Scalable Tables Management Scalable Table Creation sd_create_table ‘PhotoObj (objid BIGINT PRIMARY KEY…)’, Scalable Table Alteration sd_alter_table ‘PhotoObj ADD t INT’, 1000 sd_create_index ‘run_index ON Photoobj (run)’ sd_drop_index ‘PhotoObj.run_index’ Scalable Table Removal sd_drop_table ‘PhotoObj’

22 Application Interface: Scalable Tables Management Insert sd_insert ‘INTO PhotoObj SELECT * FROM Ceria5.Skyserver-S.PhotoObj’ Search sd_select ‘* FROM PhotoObj’ sd_select ‘TOP 5000 * INTO PhotoObj1 FROM PhotoObj’, 500

23 Application Interface See “Architecture and Interface of Scalable Distributed Database System SD-SQL Server”, IASTED-DBA 2006

24 Implementation Commands are distributed stored procedures Processed as distributed transactions at Repeatable Read isolation level See “ Prototyping a Scalable Distributed Database System SD-SQL Server”, WDAS 2006

25 Performance Analysis (1) Query (Q1) execution time (Q1) sd_select ‘COUNT (*) FROM PhotoObj’

26 Performance Analysis (2) Query (Q2) with image checking only (IC) and with image adjustment (IA) (Q2) sd_select ‘TOP x.objid FROM photoobj x, photoobj y WHERE x.obj=y.obj AND x.objid>y.objid’

27 Performance Analysis (3)  sd_select ‘COUNT (*) FROM PhotoObj’ Comparison between SD-SQL Server and SQL Server

28 Conclusion Scalable distributed partitioning of relational tables is now reality with SD-SQL Server No manual repartitioning Unlike in any other DBS we know about Performance analysis proves Efficiency of our design Immediate utility of SD-SQL Server

29 Future Works Management of replication, data failures.. Non-availability of a server…. Management of the data merging Application on other DBMSs Oracle, DB2….

30 Work partly supported by CEE Project EGov MS Research CEE Project ICONS IBM Almaden Res. Cntr., CA HP Laboratories, CA

31 Thank You Questions? Soror SAHRI Ceria, Paris-Dauphine University Journées Académiques Microsoft Paris, April 2006