Oracle Database Server 12c Pros and Cons

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1 Oracle Database Server 12c Pros and Cons Hans Forbrich Forbrich Consulting Ltd

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3 Based in Alberta, Canada

4 Fact Oracle DB 12c is the largest architectural change since Oracle8i

5 Fact Oracle documentation refers to the non- Multi-Tenant architecture as Pre-12c

6 Fact Multi-Tenant is available in ALL Editions of Oracle Database 12c. Personal Enterprise Standard

7 Fact Multi-Tenant Option is required ONLY WHEN MULTIPLE PLUGS ARE USED

8 Fact The changes in commands due to the new Multi-Tenant architecture can take a long time to become comfortable If you have been using Oracle DB since Oracle9i or older, PLAN on 6 months to retrain your fingers

9 Fact Multi-Tenant Architecture Is the FUTURE Get Used to it NOW

10 SO What has changed? And Are there concerns and benefits?

11 The way we were Background processes for each instance Reference Manual, Appendix F 99+ Background Processes *possible* For Each Instance

12 The way we were DBA access to the database:

13 The way we were And verify our database information

14 The way we were And create a new user

15 New Architecture Exactly the same but different

16 The way we need to be With the new architecture, access Service

17 Some of the Architecture changes to think about Single Instance or RAC Cluster Multiple, pluggable, databases One set of redo logs per instance One target standby One undo tablespace per instance One OR more temp tablespaces

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19 Services Not necessarily in tnsnames.ora

20 Services But each PDB has it s own service

21 Reality We use SID everywhere Many of our methods/scripts will break Any applications need to be reviewed Watch for Java, JEE apps using SID Opportunity Convert to Service NOW Decide which to use EZ-Connect, which TNS

22 Admin Scripts Many use / as sysdba Use SERVICE to get to correct container Do not use OS Authentication Many new roles: OSBACKUP, OSKM, OSDG Now need to be aware of CON_ID Not all actions at all levels Some actions restricted to ROOT Some actions may be performed at PDB

23 One SID to Bind Them One per host? SLA Patching SGA PGA Huge Pages Backup Standby

24 One Instance per host We have long wanted ONE instance per host Properly use available resources Manage memory, CPU, I/O But have had to oversize hosts for peak load And then add more instances to use free space Now this is possible But is that a good thing?

25 Before: Instances Plural!! Many background processes duplicated DBA manually balances SGA, PGA, etc No ALTER TO MOUNT Shutdown entire instance

26 Now: Instances Likely one per host!! Background processes not duplicated But may have slave processes Or threads Resource manager balances Individual databases Individually started/stopped

27 SLA $ORACLE_HOME One HOME = one Service Level Agreement Patching Everything in one HOME patched together No proper resource management Intra-Instance ONLY

28 Service Level Agreement (SLA) The Service Level Agreement is a formal (documented) or informal (discussed) agreement related to Uptime Maintenance Down time Unscheduled Down time response Patch level, patch frequency

29 Before: SLA We basically used ORACLE_HOME to implement one SLA Multiple Instances in same HOME IF they can (must be) patched together Often one HOME = one Application Tricky to administer

30 Now: SLA We basically used Instance to implement one SLA Multiple Databases in same Instance - IF they can (must be) patched together One Database = one Application? But potentially costly to administer

31 Before: Patching Many patches required some down time Especially non-rac Stop instance Apply patch Test patch Make instance available again

32 Now: Patching It may be possible to *move* the Pluggable Database (PDB) to another instance during the patch process, and then restore it after patch Minimize down time

33 Shared Global Area (Memory) SGA Multi-tenant does not significantly save on SGA, as compared to multiple instances New SGA size = Σ Individual SGA Need to size Memory & Semaphores based on possible maximum utilization to avoid restart entire instance May impact kernel configuration Interaction with Sys Admins

34 Process Global Area (Memory) PGA Theoretically fewer processes Same number of user processes Duplicate background processes eliminated However, these are all in ONE instance Need to look at PGA_AGGREGATE_TARGET May need to manually manage more sessions

35 Huge Pages (Memory) The SGA is now potentially much bigger There is NO reason to avoid Huge Pages Except that Automatic Memory Management is not compatible with Huge Pages

36 Impact on Tuning Simple Tuning involves ONE SQL statement in isolation Advanced (and recommended) Tuning involves one or more SQL concurrent statements, and interactions

37 Impact on Tuning One huge tuning problem has been the impact of non-visible resources on instance resources Other instances Other applications Multi-tenant should reduce the instances and make advanced tuning potentially simpler.

38 Backup Why do we back up? Recovery Second copy Archive With pluggable databases, we may want to re-think the purpose of backups

39 Backup differences Multi-tenant allows backup of Entire Container Database (CDB) Root only RMAN: BACKUP DATABASE ROOT; One, or more, Pluggable Databases RMAN: BACKUP PLUGGABLE DATABASE HR, ; Many backup strategies will need to be rethought

40 Backup Differences The REDO Logs are common to all PDBs Need to think about ArchiveLog backup when backing up individual PDBs Use Backup Optimization to include only those ArchiveLogs that are needed Backup *all* ArchiveLogs as a completely separate job? Recovery Catalog HIGHLY recommended

41 StandBy and High Availability RAC is fully compatible with Multi-tenant Even better, as RAC already thinks services Data Guard is another matter One standby for Container As of CREATE PLUGGABLE DATABASE includes a STANDBYS=ALL NONE

42 EM Express Enterprise Manager Too light? Suitable for quick DBA checks Cloud Control 12c Significant time investment to get started But worth it!

43 Enterprise Manager Cloud Control Cloud Control 12c ( ) is aware of Multi-Tenant

44 OEM CC Monitor and manage Instance & Cluster Monitor and manage CDB$ROOT Monitor and manage PDBs Create, Move, Destroy PDBs Everything can be scripted

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47 Cloud Control I would not want to run a multi-tenant environment without Oracle Enterprise Manager 12c Cloud Control Core is included with DB license Good graphical overview EM CLI will become very important

48 Conclusion Multi-tenant is a significant architectural change It IS the future and NOW is the time to get started There are lots of things to look at, think about and worry about Reference the Concepts Manual, Chapters 17,18 and Administrator s Guide, Chapters

49 Questions?

50 Thank You Hans Forbrich