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Oracle Utilities Tips

原创 Linux操作系统 作者:carniege 时间:2008-01-31 17:14:56 0 删除 编辑
Export Options

In addition to export modes, the export utility enables the user to specify runtime parameters interactively, on the command line, or defined in a parameter file (PARFILE). These options include:

• buffer – Specifies the size, in bytes, of the buffer used to fetch the rows. If 0 is specified, only one row is fetched at a time. This parameter only applies to conventional (non direct) exports.

• compress – When “Y”, export will mark the table to be loaded as one extent for the import utility. If “N”, the current storage options defined for the table will be used. Although this option is only implemented on import, it can only be specified on export.

• consistent – [N] Specifies the set transaction read only statement for export, ensuring data consistency. This option should be set to “Y” if activity is anticipated while the exp command is executing. If ‘Y’ is set, confirm that there is sufficient undo segment space to avoid the export session getting the ORA-1555 Snapshot too old error.

• constraints – [Y] Specifies whether table constraints should be exported with table data.

• direct – [N] Determines whether to use direct or conventional path export. Direct path exports bypass the SQL command, thereby enhancing performance.

• feedback – [0] Determines how often feedback is displayed. A value of feedback=n displays a dot for every n rows processed. The display shows all tables exported not individual ones. From the output below, each of the 20 dots represent 50,000 rows, totaling 1 million rows for the table.

About to export specified tables via Direct Path ...
. . exporting table TABLE_WITH_ONE_MILLION_ROWS
....................
1000000 rows exported


• file – The name of the export file. Multiple files can be listed, separated by commas. When export fills the filesize, it will begin writing to the next file in the list.

• filesize – The maximum file size, specified in bytes.

• flashback_scn – The system change number (SCN) that export uses to enable flashback.

• flashback_time – Export will discover the SCN that is closest to the specified time. This SCN is used to enable flashback.

• full – The entire database is exported.

• grants – [Y] Specifies object grants to export.

• help – Shows command line options for export.

• indexes – [Y] Determines whether index definitions are exported. The index data is never exported.

• log – The filename used by export to write messages. The same messages that appear on the screen are written to this file:

Connected to: Oracle9i Enterprise Edition Release 9.2.0.1.0 - Production
With the Partitioning, OLAP and Oracle Data Mining options
JServer Release 9.2.0.1.0 - Production
Export done in WE8MSWIN1252 character set and AL16UTF16 NCHAR character set

About to export specified tables via Direct Path ...
. . exporting table TABLE_WITH_ONE_MILLION_ROWS 1000000 rows exported
Export terminated successfully without warnings.

• object_consistent – [N] Specifies whether export uses SET TRANSACTION READ ONLY to ensure that the data being exported is consistent.

• owner – Only the owner’s objects will be exported.

• parfile – The name of the file that contains the export parameter options. This file can be used instead of specifying all the options on the command line for each export.

• query – Allows a subset of rows from a table to be exported, based on a SQL where clause (discussed later in this chapter).

• recordlength – Specifies the length of the file record in bytes. This parameter affects the amount of data that accumulates before it is written to disk. If not specified, this parameter defaults to the value specific to that platform. The highest value is 64KB.

• resumable – [N] Enables and disables resumable space allocation. When “Y”, the parameters resumable_name and resumable_timeout are utilized.

• resumable_name – User defined string that helps identify a resumable statement that has been suspended. This parameter is ignored unless resumable = Y.

• resumable_timeout – [7200 seconds] The time period in which an export error must be fixed. This parameter is ignored unless resumable = Y.

• rows – [Y] Indicates whether or not the table rows should be exported.

• statistics – [ESTIMATE] Indicates the level of statistics generated when the data is imported. Other options include COMPUTE and NONE.

• tables – Indicates that the type of export is table-mode and lists the tables to be exported. Table partitions and sub partitions can also be specified.

• tablespaces – Indicates that the type of export is tablespace-mode, in which all tables assigned to the listed tablespaces will be exported. This option requires the EXP_FULL_DATABASE role.

• transport_tablespace – [N] Enables the export of metadata needed for transportable tablespaces.

• triggers – [Y] Indicates whether triggers defined on export tables will also be exported.

• tts_full_check – [FALSE] When TRUE, export will verify that when creating a transportable tablespace, a consistent set of objects is exported.

• userid – Specifies the userid/password of the user performing the export.

• volsize – Specifies the maximum number of bytes in an export file on each tape volume.
The functionality of the export utility has been significantly enhanced in recent versions of Oracle. To check which options are available in any release use:

exp help=y

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