How To

Nelle ultime versioni di Oracle Database (10 e 11) è stata introdotta una nuova funzione chiamata datapump.Questo va ad affiancare i vecchi comandi exp e imp,introducendo i comanid expdp e impdp.Con questa funzione gli import e gli export non sono più delle comnuni sessioni client-server tra il nostro client oracle e il db (con tutte le limitazioni del caso),ma sono dei processi lanciati direttamente sul server (si potrà fare export e import solo su file e directory presenti sul server),questo è un vantaggio perchè oracle può amministrare le risorse da destinare a questi processi anche in base al carico di lavoro del db (finalmente non faremo sedere il db a ogni export ).Vengono introdotte anche nuove funzioni che rendono più semplice la vita del dba (per esempio la possibilità di escludere/includere solo determinate tabelle nel processo di importazione/esportazione,e nel caso della versione enterprise si può specificare il grado di parallelismo che i processi possono raggiungere,quindi impostandolo per esempio a 4 avremo un export completato in 1/4 del tempo).

Cominciamo con dare gli opportuni grant all’utente che utilizzeremo per queste operazioni.

CONN sys/password@rac10g AS SYSDBA
ALTER USER fede IDENTIFIED BY 1234 ACCOUNT UNLOCK;
GRANT CREATE ANY DIRECTORY TO fede;

A questo punto creo una directory in Oracle che punti a una directory sul mio filesystem dando relativi grants al mio utente.

CREATE OR REPLACE DIRECTORY DP_DIR AS ‘/u01/app/oracle/orabck/’;
GRANT READ, WRITE ON DIRECTORY DP_DIR TO fede;

Adesso possiamo cominciare con l’import o export di alcune tabelle,tramite il parametro TABLE,se volessimo andare a importare dei dati su una tabella già esistente dovremmo inserire anche il parametro TABLE_EXISTS_ACTION=APPEND

expdp fede/1234@rac10g  tables=ANAGRAFICA,CREDITI directory=DP_DIR dumpfile=ANAG_CRED.dmp logfile=expdpANAG_CRED.log
impdp fede/1234@rac10g  tables=ANAGRAFICA,CREDITI directory=DP_DIR dumpfile=ANAG_CRED.dmp logfile=impdpANAG_CRED.log

Se invece vogliamo importare o esportare un intero schema non utilizzeremo più i parametri FROMUSER,TOUSER oppure OWNER,ma direttamente il parametro SCHEMAS.

expdp fede/1234@rac10g schemas=CRED10G directory=DP_DIR dumpfile=CRED10G.dmp logfile=expdpCRED10G.log
impdp fede/1234@rac10g schemas=CRED10G directory=DP_DIR dumpfile=CRED10G.dmp logfile=impdpCRED10G.log

Per quanto riguarda l’import o l’export di un intero database rimane il parametro FULL=Y .

expdp fede/1234@rac10g full=y directory=DP_DIR dumpfile=CRED10G.dmp logfile=expdpCRED10G.log
impdp fede/1234@rac10g full=y directory=DP_DIR dumpfile=CRED10G.dmp logfile=impdpCRED10G.log

Tutte le operazioni di import ed export sono eseguite da dei processi sul server che fanno capo a un processo padre che li gestisce (queueing e via dicendo).Infatti se per esempio una volta lanciati uno dei comandi sopra indicati si stoppa il comando con ctrl + c,viene terminata solo la sessione con l’utente e veniamo dirottati su una console da cui per esempio possiamo lanciare il comando “status” che avrà il seguente output:

Export> status

Job: SYS_EXPORT_FULL_01
Operation: EXPORT
Mode: FULL
State: EXECUTING
Bytes Processed: 0
Current Parallelism: 1
Job Error Count: 0
Dump File: D:TEMPDB10G.DMP
bytes written: 4,096

Worker 1 Status:
State: EXECUTING
Object Schema: SYSMAN
Object Name: MGMT_CONTAINER_CRED_ARRAY
Object Type: DATABASE_EXPORT/SCHEMA/TYPE/TYPE_SPEC
Completed Objects: 261
Total Objects: 261

Come scritto prima possiamo impostare il grado di parallelismo con cui lanciare lìexport o l’import attraverso il parametro PARALLEL e l’utilizzo della wildcard %U in modo tale che più file di export possano essere creati contemporaneamente.

expdp fede/1234@rac10g schemas=CRED10G PARALLEL=4 directory=DP_DIR dumpfile=CRED10G%U.dmp logfile=expdpCRED10G.log

La vista DBA_DATAPUMP_JOBS può essere controllata per verificare lo stato dei jobs lanciati sul server.

system@rac10g> select * from dba_datapump_jobs;

OWNER_NAME JOB_NAME OPERATION
—————————— —————————— ——————————
JOB_MODE STATE DEGREE ATTACHED_SESSIONS
—————————— —————————— ———- —————–
SYSTEM SYS_EXPORT_FULL_01 EXPORT
FULL EXECUTING 1 1

Possono anche essere utilizzati i parametri EXCLUDE e INCLUDE per filtrare gli oggetti da processare.

expdp fede/1234@rac10g schemas=CRED10G include=TABLE:”IN (‘ANAGRAFICA’, ‘CREDITI’)” directory=DP_DIR dumpfile=CRED10G.dmp logfile=expdpCRED10G.log
impdp fede/1234@rac10g schemas=CRED10G exclude=TABLE:”= ‘CREDITI’” directory=DP_DIR dumpfile=CRED10G.dmp logfile=impdpCRED10G.log

Nel caso dopo aver lanciato expdp abbiamo chiuso la finestra e vogliamo ritornarci per controllare lo stato,possiamo come prima cosa interrogare la vista DBA_DATAPUMP_JOBS,da li ricavarci il JOB_NAME e quindi eseguire il seguente comando.

expdp system/***** attach=SYS_EXPORT_FULL_01
Export: Release 10.1.0.4.0 – 64bit Production on Tuesday, 20 March, 2007 23:53
Copyright (c) 2003, Oracle. All rights reserved.
Connected to: Oracle Database 10g Enterprise Edition Release 10.1.0.4.0 – 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options
Job: SYS_EXPORT_TABLE_03
Owner: SYSTEM
Operation: EXPORT
Creator Privs: FALSE
GUID: 2C22B38216C04297E044000E7FEDD1FD
Start Time: Tuesday, 20 March, 2007 23:53
Mode: TABLE
Instance: *****
Max Parallelism: 4
EXPORT Job Parameters:
Parameter Name Parameter Value:
CLIENT_COMMAND system/******** parfile=/backup/****/PARFILES/userdata_tablename.dat
DATA_ACCESS_METHOD AUTOMATIC
ESTIMATE BLOCKS
INCLUDE_METADATA 1
LOG_FILE_DIRECTORY DATA_PUMP_DIR2
LOG_FILE_NAME expdp_tablename_20032007.log
TABLE_CONSISTENCY 0
State: IDLING
Bytes Processed: 0
Current Parallelism: 4
Job Error Count: 0
Dump File: /backup/****/expdp_tablename_20032007.dmp
bytes written: 180,224
Worker 1 Status:
State: UNDEFINED
Worker 2 Status:
State: UNDEFINED
Object Schema: *****
Object Name: *****
Object Type: TABLE_EXPORT/TABLE/TBL_TABLE_DATA/TABLE/TABLE_DATA
Completed Objects: 1
Total Objects: 1
Worker 3 Status:
State: UNDEFINED
Worker 4 Status:
State: UNDEFINED

Per avere maggiori informazioni su datapump consiglio di guardare l’help sia dei comandi impdp che di expdp.

expdp help=y

Export: Release 10.1.0.2.0 – Production on Tuesday, 23 March, 2004 8:33

Copyright (c) 2003, Oracle. All rights reserved.

The Data Pump export utility provides a mechanism for transferring data objects
between Oracle databases. The utility is invoked with the following command:

Example: expdp scott/tiger DIRECTORY=dmpdir DUMPFILE=scott.dmp

You can control how Export runs by entering the ‘expdp’ command followed
by various parameters. To specify parameters, you use keywords:

Format: expdp KEYWORD=value or KEYWORD=(value1,value2,…,valueN)
Example: expdp scott/tiger DUMPFILE=scott.dmp DIRECTORY=dmpdir SCHEMAS=scott
or TABLES=(T1:P1,T1:P2), if T1 is partitioned table

USERID must be the first parameter on the command line.

Keyword Description (Default)
——————————————————————————
ATTACH Attach to existing job, e.g. ATTACH [=job name].
CONTENT Specifies data to unload where the valid keywords are:
(ALL), DATA_ONLY, and METADATA_ONLY.
DIRECTORY Directory object to be used for dumpfiles and logfiles.
DUMPFILE List of destination dump files (expdat.dmp),
e.g. DUMPFILE=scott1.dmp, scott2.dmp, dmpdir:scott3.dmp.
ESTIMATE Calculate job estimates where the valid keywords are:
(BLOCKS) and STATISTICS.
ESTIMATE_ONLY Calculate job estimates without performing the export.
EXCLUDE Exclude specific object types, e.g. EXCLUDE=TABLE:EMP.
FILESIZE Specify the size of each dumpfile in units of bytes.
FLASHBACK_SCN SCN used to set session snapshot back to.
FLASHBACK_TIME Time used to get the SCN closest to the specified time.
FULL Export entire database (N).
HELP Display Help messages (N).
INCLUDE Include specific object types, e.g. INCLUDE=TABLE_DATA.
JOB_NAME Name of export job to create.
LOGFILE Log file name (export.log).
NETWORK_LINK Name of remote database link to the source system.
NOLOGFILE Do not write logfile (N).
PARALLEL Change the number of active workers for current job.
PARFILE Specify parameter file.
QUERY Predicate clause used to export a subset of a table.
SCHEMAS List of schemas to export (login schema).
STATUS Frequency (secs) job status is to be monitored where
the default (0) will show new status when available.
TABLES Identifies a list of tables to export – one schema only.
TABLESPACES Identifies a list of tablespaces to export.
TRANSPORT_FULL_CHECK Verify storage segments of all tables (N).
TRANSPORT_TABLESPACES List of tablespaces from which metadata will be unloaded.
VERSION Version of objects to export where valid keywords are:
(COMPATIBLE), LATEST, or any valid database version.

The following commands are valid while in interactive mode.
Note: abbreviations are allowed

Command Description
——————————————————————————
ADD_FILE Add dumpfile to dumpfile set.
ADD_FILE=dumpfile-name
CONTINUE_CLIENT Return to logging mode. Job will be re-started if idle.
EXIT_CLIENT Quit client session and leave job running.
HELP Summarize interactive commands.
KILL_JOB Detach and delete job.
PARALLEL Change the number of active workers for current job.
PARALLEL=.
START_JOB Start/resume current job.
STATUS Frequency (secs) job status is to be monitored where
the default (0) will show new status when available.
STATUS=[interval]
STOP_JOB Orderly shutdown of job execution and exits the client.
STOP_JOB=IMMEDIATE performs an immediate shutdown of the
Data Pump job.

impdp help=y

Import: Release 10.1.0.2.0 – Production on Saturday, 11 September, 2004 17:22

Copyright (c) 2003, Oracle. All rights reserved.

The Data Pump Import utility provides a mechanism for transferring data objects
between Oracle databases. The utility is invoked with the following command:

Example: impdp scott/tiger DIRECTORY=dmpdir DUMPFILE=scott.dmp

You can control how Import runs by entering the ‘impdp’ command followed
by various parameters. To specify parameters, you use keywords:

Format: impdp KEYWORD=value or KEYWORD=(value1,value2,…,valueN)
Example: impdp scott/tiger DIRECTORY=dmpdir DUMPFILE=scott.dmp

USERID must be the first parameter on the command line.

Keyword Description (Default)
——————————————————————————
ATTACH Attach to existing job, e.g. ATTACH [=job name].
CONTENT Specifies data to load where the valid keywords are:
(ALL), DATA_ONLY, and METADATA_ONLY.
DIRECTORY Directory object to be used for dump, log, and sql files.
DUMPFILE List of dumpfiles to import from (expdat.dmp),
e.g. DUMPFILE=scott1.dmp, scott2.dmp, dmpdir:scott3.dmp.
ESTIMATE Calculate job estimates where the valid keywords are:
(BLOCKS) and STATISTICS.
EXCLUDE Exclude specific object types, e.g. EXCLUDE=TABLE:EMP.
FLASHBACK_SCN SCN used to set session snapshot back to.
FLASHBACK_TIME Time used to get the SCN closest to the specified time.
FULL Import everything from source (Y).
HELP Display help messages (N).
INCLUDE Include specific object types, e.g. INCLUDE=TABLE_DATA.
JOB_NAME Name of import job to create.
LOGFILE Log file name (import.log).
NETWORK_LINK Name of remote database link to the source system.
NOLOGFILE Do not write logfile.
PARALLEL Change the number of active workers for current job.
PARFILE Specify parameter file.
QUERY Predicate clause used to import a subset of a table.
REMAP_DATAFILE Redefine datafile references in all DDL statements.
REMAP_SCHEMA Objects from one schema are loaded into another schema.
REMAP_TABLESPACE Tablespace object are remapped to another tablespace.
REUSE_DATAFILES Tablespace will be initialized if it already exists (N).
SCHEMAS List of schemas to import.
SKIP_UNUSABLE_INDEXES Skip indexes that were set to the Index Unusable state.
SQLFILE Write all the SQL DDL to a specified file.
STATUS Frequency (secs) job status is to be monitored where
the default (0) will show new status when available.
STREAMS_CONFIGURATION Enable the loading of Streams metadata
TABLE_EXISTS_ACTION Action to take if imported object already exists.
Valid keywords: (SKIP), APPEND, REPLACE and TRUNCATE.
TABLES Identifies a list of tables to import.
TABLESPACES Identifies a list of tablespaces to import.
TRANSFORM Metadata transform to apply (Y/N) to specific objects.
Valid transform keywords: SEGMENT_ATTRIBUTES and STORAGE.
ex. TRANSFORM=SEGMENT_ATTRIBUTES:N:TABLE.
TRANSPORT_DATAFILES List of datafiles to be imported by transportable mode.
TRANSPORT_FULL_CHECK Verify storage segments of all tables (N).
TRANSPORT_TABLESPACES List of tablespaces from which metadata will be loaded.
Only valid in NETWORK_LINK mode import operations.
VERSION Version of objects to export where valid keywords are:
(COMPATIBLE), LATEST, or any valid database version.
Only valid for NETWORK_LINK and SQLFILE.

The following commands are valid while in interactive mode.
Note: abbreviations are allowed

Command Description (Default)
——————————————————————————
CONTINUE_CLIENT Return to logging mode. Job will be re-started if idle.
EXIT_CLIENT Quit client session and leave job running.
HELP Summarize interactive commands.
KILL_JOB Detach and delete job.
PARALLEL Change the number of active workers for current job.
PARALLEL=.
START_JOB Start/resume current job.
START_JOB=SKIP_CURRENT will start the job after skipping
any action which was in progress when job was stopped.
STATUS Frequency (secs) job status is to be monitored where
the default (0) will show new status when available.
STATUS=[interval]
STOP_JOB Orderly shutdown of job execution and exits the client.
STOP_JOB=IMMEDIATE performs an immediate shutdown of the
Data Pump job.