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Oracle 10g Database Engine New Features For Techies

ORACLE 10g

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• What’s behind the 10g buzzwords• Manageability enhancements• Performance tuning enhancements• Exp/imp with Data Pump• Parameters, views• SQL and PL/SQL• Recovery and Flashback• Wrap-up • Questions

Agenda

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Simplicity vs Flexibility• Automatic statistics gathering• Advisories • Automatic tuning• Less than 30 basic (init.ora) parameters

– Basic, advanced, hidden parameters

• Easier operations– alter tablespace rename– flashback queries– “undrop” table– etc..

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Manageability• SGA_TARGET

– Sets total size for all SGA components– Buffer Cache, Shared Pool, Large Pool, Java Pool– Dynamically and automatically adjustable– Automatic changes persist in SPFILE

• PGA_AGGREGATE_TARGET– Available since 9i– Sets total size target for all server processes– sort_area_size, sort_area_retained_size,

hash_area_size, bitmap_merge_area_size– Contents automatically managed

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Basic ParametersCOMPATIBLECONTROL_FILESDB_BLOCK_SIZEDB_CREATE_FILE_DESTDB_CREATE_ONLINE_LOG_DESTDB_DOMAINDB_NAMEDB_RECOVERY_FILE_DESTDB_RECOVERY_FILE_DEST_SIZEINSTANCE_NUMBERJOB_QUEUE_PROCESSESLOG_ARCHIVE_DEST_nLOG_ARCHIVE_DEST_STATE_n

NLS_LANGUAGENLS_TERRITORYOPEN_CURSORSPROCESSESREMOTE_LISTENERREMOTE_LOGIN_PASSWORDFILEROLLBACK_SEGMENTSSESSIONSSHARED_SERVERSSTAR_TRANSFORMATION_ENABLEDUNDO_MANAGEMENTUNDO_TABLESPACE

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Manageability• SYSAUX tablespace for system utilities

Module Tablespace

SYS objects SYSTEM (includes AUD$ and FGA_LOG$ tables)

Oracle Data Mining ODM

OEM Repository OEM_REPOSITORY

Oracle OLAP CWMLITE

Oracle interMedia SYSTEM

Oracle Spatial SYSTEM

Oracle Ultra Search DRSYS

RMAN Recovery Catalog TOOLS

Sample Schemas Example

Workspace Manager SYSTEM

Oracle XML DB XDB_RESINFO

Auto. Workload Repository New in 10g

SYSAUX

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Online Operations• Some functionality there already in 8i, 9i

– Online index build, rebuild– Online index organized table rebuild– Analyze/validate structure online

• Online table redefinition– dbms_redefinition package starting from 9i– change table physical structure online– allows adding, changing, removing columns

online

• Rolling database upgrade– Requires Logical Standby database

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Online Segment Shrink• Can be recommended by Segment Advisor

• alter table enable row movement;• alter table t1 shrink space cascade;

TABLE HEADER 01010101

110110101100110100001101 10111101

1100110110101111111011010000110110111101

High Water Mark

TABLE HEADER 11001101

00001101

11001101101011111110110100001101

11001101101011111110110100001101

High Water Mark Free Space

Free Space

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Rename Tablespace• Useful in Transportable Tablespace

scenarios• ALTER TABLESPACE prod RENAME to arc1;

– Can’t rename SYSTEM or SYSAUX– Tablespace and all datafiles must be online– Can also rename READ ONLY tablespaces

PROD ARC1

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Temporary Tablespace Groups• Can create several temporary tablespaces

and assign them to a tablespace group• Can assign the tablespace group as users

temporary tablespace• Parallel Query and Parallel execution slaves

can spread temporary segments on different tablespaces– alter tablespace temp1 tablespace group t;– create temporary tablespace temp2 tempfile

'temp2_01.dbf' size 100m tablespace group t;– alter tablespace temp1 tablespace group '';

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Bigfile Tablespaces• Support for sizes up to 8 Exabytes!

– 8 000 000 Terabytes– Max 65535 files in database– SYSTEM & SYSAUX can’t be bigfile tablespaces

• CREATE BIGFILE TABLESPACE bigtbsDATAFILE '/u02/oracle/data/bigtbs01.dbf‘SIZE 50G EXTENT MANAGEMENT LOCAL SEGMENT SPACE MANAGEMENT AUTO;

8 000 000 000 000 000 000 bytes

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Who Needs This?!• Who could possibly outgrow previous

database size limits?• 9i limits 65534 files per database• 222-1=4,194,303 blocks per datafile• 32kB max blocksize (not on all platforms)• Total max size of 9i database:

– 65534*4194303*32 kB≈8055 TB≈8 Petabytes!– 38000*4194303*16 kB≈2.5 Petabytes!– Practical size limit in reality is even smaller

• CERN in Switzerland: 5-8 PB data per year

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Crossplatform Transportable TSRMAN> CONVERT TABLESPACE sales_1,sales_22> TO PLATFORM ’Microsoft Windows NT’3> FORMAT ’/temp/%U’;...Transporting Tablespaces Between Databasesinput datafile fno=00004 name=/u01/oracle/oradata/salesdb/sales_101.dbf

converted datafile=/temp/data_D-10_I-3295731590_TS-EXAMPLE_FNO-4_06ek24vl

channel ORA_DISK_1: datafile conversion complete, elapsed time: 00:00:45

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Data Pump• A server-managed data transportation tool• Direct load/extract capabilities• Very high performance/efficient with large

data sets• Replacement for exp/imp

– old exp/imp remain supported

PRODData

Warehouse

Data Pump

DataPumpClient

Data Pump

DataPumpClient

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Data Pump• Commands expdp/impdp• Can use files or direct network transfer• Dynamic configuration, resumable

operations• Client can detach and reconnect• Can be parallelized using PARALLEL

– Even loads to/from external text files– Parallelization level can be changed on the fly

for long running jobs

• Monitored through DBA_DATAPUMP_JOBS

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Data Pump Options• Fine-Grained Object Selection

– exclude=function– exclude=procedure– exclude=package:”like ‘PAYROLL%’ ”– include=table– content=metadata_only | data_only | both– query=“modify_date > sysdate-1”

• DDL Transformations, DDL extract• table_exists_action

– skip, append, truncate, replace

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FlashBack Database• Flash Recovery Area must be configured

– Flashback logs are stored there– Consisting of old database block images– Fast “rollback” of database, no redologs

required

DB Flashback Log

ServerProcess

ServerProcessServer

Process

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FlashBack Database

Configuration parameters:• DB_RECOVERY_FILE_DEST• DB_RECOVERY_FILE_DEST_SIZE• DB_FLASHBACK_RETENTION_TARGETCommands:• ALTER DATABASE FLASHBACK ON;• ALTER DATABASE FLASHBACK OFF;• ALTER TABLESPACE test1 FLASHBACK OFF;• ALTER TABLESPACE test1 FLASHBACK ON;

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FlashBack Options

Flashback Query:• exec dbms_flashback.enable_at_time(…);• select * from table;• exec dbms_flashback.disable;• select * from table AS OF timestamp ‘…’;Flashback Table:• FLASHBACK TABLE t1 TO SCN 12345;• FLASHBACK TABLE t1 TO TIMESTAMP '2003-

03-03 12:05:00';

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Flashback Row HistorySELECT versions_xid XID, versions_startscn START_SCN,

versions_endscn END_SCN, versions_operation OPERATION,

empname, salary FROM hr.employees_demo

VERSIONS BETWEEN SCN MINVALUE AND MAXVALUE

where empno = 111;

XID START_SCN END_SCN OPERATION EMPNAME SALARY

--- --------- ------- --------- ------- ------

0004000700000058 113855 I Tom 927

000200030000002D 113564 D Mike 555

000200030000002E 112670 113564 I Mike 555

3 rows selected

• Useful for auditing

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Flashback Transaction Historyselect xid, start_scn, commit_scn, operation,

undo_sql, table_namefrom dba_transaction_query where xid = ’000200030000002D’;XID START_SCN COMMIT_SCN OPERATION UNDO_SQL--- --------- ---------- --------- -------------------------000200030000002D 112670 113565 D insert into "SCOTT"."EMP"("EMPNO","EMPNAME","SALARY") values ('111','Mike','655')

000200030000002D 112670 113565 I delete from "SCOTT"."DEPT"where "DEPTNO" = '20' and "DEPTNAME" = 'Finance'

000200030000002D 112670 113565 D update “SCOTT”.”EMP”set “SALARY” = ‘555’ where “EMPNO” = ‘111’ and ”EMPNAME” =

‘Mike’ and “SALARY”= ‘655’3 rows selected

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Table Recovery using Flashback• DROP TABLE X;

– Table is renamed internally, not dropped– Indexes & other structures remain– Table is purged when out of free space or quota

• SELECT * FROM RECYCLEBIN;– Systemwide recyclebin DBA_RECYCLEBIN– Or show recyclebin command in sqlplus

• FLASHBACK TABLE RB$$3560$TABLE$1TO BEFORE DROP RENAME TO scott.emp;

• PURGE RECYCLEBIN;• DROP TABLE X PURGE;

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Performance Tuning• RBO is dead, long live the CBO!

– Even data dictionary, SYS tables using CBO– However, RBO is gone nowhere, it’s available

• Optimizer able to use run-time statistics– exec dbms_stats.gather_system_statistics(…)– OPTIMIZER_DYNAMIC_SAMPLING (default: 2)

• Multiple Advisors– SQL Access & Tuning Advisor– Memory Advisors (SGA, Shared Pool, etc..)– Segment Advisor (Fragmentation, etc..)– Undo Advisor

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Advisor Information• DBA_ADVISOR_FINDINGS• DBA_ADVISOR_RECOMMENDATIONS• DBA_ADVISOR_RATIONALE• And many more…• All the information is accessible through

DBA_ and V$ data dictionary views• The reasons and rationale behind

recommendations can be seen

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Performance Troubleshooting• Automatic Workload Repository

– Runtime execution statistics are gathered in memory

– MMON background process flushes stats to disk

• V$SQL_BIND_CAPTURE– Samples bind variables for all sessions– Faster than sql_trace (10046 trace on level 4)– But doesn’t capture all variable types– And doesn’t capture occurences of bindings

• _cursor_bind_capture_interval defaults to 900 seconds

– Good for getting samples of database operations

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Performance Troubleshooting (2)• Event, P1, P2, P3 columns in V$SESSION for

quick diagnosis– the same information that in V$SESSION_WAIT

• dbms_monitor package– set tracing and statistics gathering in sessions

based on sessionid, client_id, module and action attributes

– RAC aware, monitoring remains active until explicitly disabled

• trcsess tool for gathering sessions SQL from in shared server environment– Sql trace (10046) reports module, action,

client_id information to trace file

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Improved Timing and Statistics• Old methods

– V$SESSION_EVENT, V$SYSTEM_EVENT– V$SYSSTAT, V$SESSTAT, V$FILESTAT, – Contained cumulative information since startup

• New opportunities– V$EVENTMETRIC, V$SESSMETRIC, V$SYSMETRIC,

V$FILEMETRIC– V$SYSMETRIC_HISTORY,

V$SESSION_WAIT_HISTORY– Contain same statistics, but sampled over

interval, also history views

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SQLPLUS ChangesImprovements• SPOOL CREATE | REPLACE | APPEND

– also works for SAVE command

• SHOW RECYCLE BIN• SQLPROMPT runtime variable substitution

– SET SQLPROMPT "_USER'@'_CONNECT_IDENTIFIER >"

• glogin.sql and login.sql scripts are executed also on CONNECT

Deimprovements• No graphical sqlplusw.exe in Windows• COPY command deprecated

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Other• dbms_scheduler

– calendar Expressions: Yearly, Monthly, Weekly, Daily, Hourly, Minutely, Secondely

• alter system flush buffer_cache;• drop database;

– database must be closed– mounted exclusively– restricted

• default user tablespace– specifies default tablespace for new users,

similar to default temporary tablespace in 9i

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Conclusion• This was probably < 1% of all new features• Lot’s of new features = lot’s of new bugs• Automatic for small to medium systems• Big & heavily loaded systems still need care

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Oracle 10g Database Engine

Thank you!