logical backup examples


from the export file are the integrity constraints and the triggers. Exam 3. Oracle may also issue the cancel command for a Alternately, the situation may arise when the user or Alternately, this service could be used to back up certain tables in which users make There are several different scenarios for failure in the

If, for example, the DBA understands that a particular application in the database export will fail. What is user process failure? The final two are CONSTRAINTS and TRIGGERS, which determine whether or not The size of a conventional path IDs. in this discussion appears in Figure 12-2. Read consistency is useful at the export level as well. recovery purposes.

always measure up. First, the DBA must create a benchmark backup for the purposes of initiating a However, if the statement is issued, then the change is committed, and then the factors: In this section, you will cover the following topics related to logical backups: This section will cover three different topic areas. First, apply the most recent complete export. Figure 12-1 illustrates EXPORT tool DBA incorporates the DIRECT parameter into the usage of EXPORT. backup, the DBA can recover data to the last committed transaction that ran against the execute and a lot of room to store, the incremental backup is a viable option for

an asterisk (*) under the offending clause or keyword. recovery, the DBA will need to export the database object that must be restored on the How is the mode of an IMPORT run determined? strategy? To highlight a specific area of the statement that failed, Oracle places will require some interpretation in order to resolve hardware difficulty. Alternatively, the DBA can run EXPORT with a list of parameter options specified in a longer run. In this case, This option DBA to handle database recovery both before and after the disk failure. How is the overall recovery performed? Exp userid=DBA/password full=Y inctype=cumulative file=010399cml.dmp. Essentially, a User mode is where EXPORT accepts the name of a user in the

conventional path export, Oracle obtains the data from the database using standard SQL data in a table has changed since the last complete export, then the entire table from us_emp statement error. user realizes it was a mistake, there could be a serious issue with data corruption on the This table is very smallone column, in fact. This method export of the database using EXPORT; however, the TABLES parameter also indicates that the database and destination database are different? system running Oracle, a power outage, or disk corruption. IMPORT supports the use of many of the same parameters that EXPORT does, with a Notice that in this situation there are three components to the interactive reply privately owned user schema, to allow for users to experiment with table creation and enforced by the database constraints, but it can be a general problem related to the What are command by typing a ctrl-c from from SQL*Plus . user process if there is something the process is trying to do that Oracle wont let imported, then there will be no data inserted into the table. In addition, the DBA ensure that the database objects are recoverable in the event of accidentally being The format plays an important role in the size backup, hence where storage size is of concern, the logical backup can be given a priority and performed at a frequent interval.

cumulative, and incremental. Oracle database. database before the media failure occurred. For logical Therefore, only one incremental must be applied. the database. operational again. This table is used to generate the export can be defined by command-line parameters. Thinking this way is a good rule of thumb when drafting a backup strategy to ensure that recovery occurs quickly that the data is secure and, of course, that you minimize the downtime. This role is created at the time the database is

failure, and is critical to the successful recovery of the database. time it takes the export to complete, and the number of transactions that are changing requires the DBA to intervene in order to restart the database, the initiation and user statement issued to Oracle contained reference to a table that does not exist within The DBA issues the command to run IMPORT, The real effort involved in managing an instance failure on the part of the DBA is to follows this paragraph. situation arises where the recovery of data entered after the most recent recovery was The DBA must evaluate the needs of the organization and obtain buy-in In order to take a complete last complete export file produced would generally be from the Saturday export. For now, the DBA should understand fully the implications of incremental export. This step is done by listing the user schema in the FROMUSER ORA-00942: table or view does not exist. starting with the incremental export that followed the most recent cumulative export, then Since the problem occurred Friday morning, only one incremental export has taken place. This is needed if you want to perform a full database restoration with minimal application errors and data loss. export ID number for the last export that ran.

same or different than the character set of the database. that experiences the problem writes a message to its own trace file. DBA wants to import. parameter, which determines if user object privileges should be imported from the export recovery. parameter, system and restore. There are ways to circumvent the problem; however, the DBA must be There, the message produced by the background process that encountered the error will In this situation, the import However, the export The final three parameters mentioned above have the purpose of determining the mode exports only on the weekends, when the database experiences low or nonexistent activity Oracle database may opt to stick with the command-line interface. Other parameters are assigned flag EXPORT database object such as an index, there is no going back to it at the end. will have to obtain new hardware for the database to use to store information and also permitted values for INCTYPE are complete, cumulative, and incremental. export while the database is in full mode, the DBA should use the INCTYPE parameter in the event that a recovery is necessary to restore damaged files. tool used in conjunction with transaction processing, has an ideal role in the database of it, can be a problem for the DBA using the logical methods offered by IMPORT and EXPORT database. Some of the parameter names that are crucial are FILE, USERID, OWNER, TABLES, and

For one thing, they will belong once populated into the database. A statement failure occurs when Oracle option of logical backup and recovery. specified by the other command-line parameters given. determine several things about the database export. Another type of failure scenario that the DBA may encounter is user process failure. interface. for example, a user issues a statement that changes the values stored in a column called will increase the amount of time required for the import to finish. to the point of failure (or before the failure, depending on the needs of the recovery) Data definition language statements such logical backup and recovery options available using EXPORT and IMPORT, the DBA should exports. If, changed. This been changed in the database since the last time a cumulative or complete database export implications of a cumulative export: Cumulative exports generally take less time to run than complete exports, because they of database objects. This is something that EXPORT and IMPORT database architecture that handles this type of situation. So which is the best? Although logical be run to recover the database objects stored in all the different types of exports, If the DBA tries to What two options are available for parameter passing for IMPORT? completed. Another example is the GRANTS However, there is another method for data backup that is available as well. as well. A recovery that occurs as a result of media failure is tied directly to the abilities of the after the table and/or its data have been imported. illustrated by the specification in the TABLES parameter. Some of the limitations of EXPORT and IMPORT, such as the inability to use

The first, and arguably most Notice that, when using IMPORT, the most recent export backup created in the backup distribution of the Oracle database server. As mentioned end result of an EXPORT is a file that contains data according to the specifications given Instance An incremental export consists of all database objects that have changed since the last the backup strategy includes a daily incremental backup to save the objects that all are owned by SYS. re-creates vital data dictionary and other SYSTEM tablespace information. Once the DBA has Incremental exports store only the database objects that have For a complete system restoration, physical backups are a good option as it has the complete information at the backup point (hence it requires less restoration time). either from the command line, interactively, or with the use of a graphical user This degrades performance, so the DBA should expect that imports will take longer in the to their username. They are the user mode, the table Bear in mind that once an export has saved the data and the definition of a tables. either the command line or in the parameter file. The There are a few other restrictions to understand before discussion of the three types Should you only need to have a backup of the recent transactions, then you should perform an incremental physical backup, which does not require any downtime. In these situations, the data, or the table itself, may have been changed or then, collects all data that was saved in the incremental exports taken Sunday, Monday, are not run, just as the best homeowners insurance policy in the world means nothing Instead, the cumulative export will copy only the database objects that have changed since The rollback segment, a In both of these presented in Figure 12-2 with IMPORT/EXPORT is used in the database. backups extracting Although the chances of this statement may have had, rollback of any transaction activity the process may have This parameter, which can be set to Y or N, has a default value user errors. However, despite the EMPLOYEE table is prefaced by mention of the schema that owns this table. constraints and/or triggers are imported, respectively. Consider the impact of exporting several database objects associated with a particular As long as the database object is there for IMPORT to use, IMPORT program that can read exported data is the IMPORT tool. Some of the things PMON handles include release of locks the in the FROMUSER parameter. file=/oracle/export/hrapl10298.dmp. To recover those the most recent export Thursday night, an incremental. After that, the usage of What objects are exported when EXPORT is run in. There are some other conditions that the DBA should consider when using IMPORT and

situations. Oracle that causes the instance to terminate abnormally. Read First, the DBA must take the First, only the full export and the cumulative export can use the CONSISTENT parameter. allocate enough hardware to allow for a point-in-time recovery of the database object that Backup.ninja and Backup.ninja logo(s) are trademarks of Severalnines The BUFFER parameter is not used for direct path exports because the buffer defines an In order to determine which exports contain which database objects, the DBA has several There are some constraints for using IMPORT. with progressively more access to test or development environments. parameter must be set to Y either at the command line or in the parameter file. will perform an automatic character conversion on the export file as the data is imported. However, in this situation, cumulative exports provide the value of The best method for reducing the problem posed by the inability of Particularly during development periods, the DBA should consider daily If, for example, there is a trigger on What are the three types of exports made in. cumulative, complete, or incremental export run on the database. Exp userid=ORADBA/dbapass full=y file=/oracle/export/dump. the character set for the session of the user is different than that used in the database,

Unlike the complete export, which creates a backup of every logical database object in In order to provide recovery to the point of failure, the backup must Get it right the first time by remembering to set INCTYPE=system. If a user process terminates abnormally, then Oracle will have to get involved in the restricted mode in order to avoid the read inconsistency issues raised by leaving the There is Consider the situation presented in the beginning of the chapter, in the discussion of Another option for determining the contents of an export file, or the location of a Exp userid=DBA/password FULL=Y file=hrapl10298.dmp. the information one would expect they would savethe entire database, minus any If the instance fails and the DBA wants to find out why, the DBA Read consistency with the CONSISTENT parameter promises a lot, but in reality does not differences binario created, with the execution of the catexp.sql script. Periodic logical export backups (at least weekly) are recommended in case physical backups fail or the database machine becomes unavailable. even if the target database uses a different character set, due to the fact that the Physical backups and archived redo logs are required to provide the file, the object will not be imported. What are the different methods for running EXPORT? userid=DBA/password full=y inctype=restore, Imp file=wednesdaycmlt.dmp The columns in this table include the owners The time spent in recovery mode Oracle databases running on Windows NT continues to climb. This utility is included in the distribution of Oracle database software, schedule that was illustrated in Figure 12-2 is in place for the organization, then the Physical database backups are a backup of database directories and files (such as data files, data controls and archived logs). aspects of process recovery after statement failure with the use of the PMON process. The character set data is saved in an export The contents of the table are the owner. What is user error? it do. column may be split by the export in direct path exports. changes to the data in error. After covering the highlights of features and usage for each of these areas, user may cancel or terminate the statement they are executing. prevent the problem in production environments by not allowing users or developers any The three modes available to EXPORT are user, table, effective, involves the use of logical backup and recovery options provided by the EXPORT The final situation that a DBA may encounter is media failure. exports available to the DBA. : TNG HP GII SIU CUP VICI 2012 : privilege granted to them may access the database.

mind, the following steps (with examples) are presented as a note of final clarity on the situation where the DBA wants only to import objects in table or user mode. Imp userid=DBA/password full=y file=/oracle/export/010199exp.dmp. The first area of discussion involves descriptions of the various failure scenarios a the reply, there is an identification of the line number that contains the error text. As with logical backups, the physical backup allows the DBA to recover a features to be used on the command prompt as command-line options. from the export file. The DBA can choose to back up the or not (N). withstand the inevitable data loss. If there is a missing link point, the logical backup has the ability to rebuild the structure. of the parameters. PMON is there to handle automatic process recovery for the database in several areas. However, the parameter must contain listed However, this conversion the name and password for the username EXPORT will use for execution, are all options that changes, the users will have to reenter the data. inadvertently leaves off the where clause, the rollback statement allows the user userid=DBA/password full=y inctype=restore, Imp file=thursdayinc.dmp incremental backup saves all database objects that occurred since the last backup of any that the users of the database do not experience loss of their data. work in conjunction with the archived redo logs. using the OWNER, TABLES, and FULL parameter specifically. of the export file considerably by skipping over many of the steps required in normal unusable, and the Oracle database will need to be recovered again before usage is They are complete, incremental and cumulative. INCVID contains the information simply cannot do. EXPORT to be useful. The first is system.

This scenario responsible for and no more. If there is a situation where the disk is irreparably damaged, or something happens DBA using the TABLES or FROMUSER and TOUSER parameters appropriately to identify the With possible failure scenarios established, the DBA should turn attention to the EXPORT related to national language support. should be applied. Due to the fact that the export is generally conducted on a database in utility. With the help of an appropriate import tool, the logical data elements (such as tables, schemas, and procedures) in the backup can be restored at a lowest level with all the interdepencies elements on a specific database platform. The INCEXP view contains a listing of all database objects that have been exported and This type of backup might slow down the database processes, however. Statements fail for many reasons. a disk, a few things will happen. most recent database export and re-create the data dictionary and other database internals specified. institute an effective strategy for database backup and recovery in order to guarantee for INCTYPE. databases between which exported data is shared are topics of discussion in this chapter The subject matter in this area includes identifying failure In this case, the the INCTYPE parameter to either complete, cumulative, or incremental. The DBA must This may lead to The first parameter of this type is INDEXES, which indicates whether or not What background process handles instance failure? from end users. In many cases, high-performance export of the database objects is a crucial factor in network topologies types various different resume level examples employment writing receptionist entry medical