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DUL Allows recovery of data from raw datafiles
Download executable for your desired platform
Best Practice: If going on-site, download all platforms ahead of time in case internal Oracle access is later prohibited.
Download current exe zip/gz file for platform
DUL Utility (Note: date effective copy protection)
Oracle DUL Data Unloader data recovery tool information summary
Oracle DUL is the internal database recovery tool of Oracle, developed by Dutch Oracle Support, Bernard van Duijnen:
- DUL is not a product of Oracle
- DUL is not supported by Oracle
- DUL is strictly limited to Oracle Support after-sales support department for internal use
- Using DUL abroad should go through Oracle’s internal approval, before using you need to purchase Oracle’s standard services PS first, otherwise it is not even eligible to use DUL
- One reason DUL is strictly controlled is its use of the Oracle source code
Start from DUL 9, Bernard van Duijnen set a software time lock for DUL to prevent the external use of DUL. He compiled DUL compiled on different platforms (DUL base on the C language) and uploaded to ORACLE internal DUL workspace (base on stbeehive space) periodically, and then Oracle Support downloaded it by using the internal VPN login. For example, Bernard.van.duijnen released a version on October 1. The date lock is 30 days. This version basically will become invalid by the time of November 1. And DUL does not read OS time, so changing OS time is useless. In fact, it reads a current time recorded by Oracle’s data file. And normal users won’t change the time to use DUL.
Note that Bernard van Duijnen does not provide DUL on HP-UX, so no DUL version can be applied to HP-UX.
Also note that earlier versions of DUL cannot be used in the current version 10g, 11g, 12c database, because it’s too old. Using DUL in the United States is restricted. In China, basically only the Oracle ACS customer service department provides external use, and the price of ORACLE ACS field services is fairly expensive.
The attached document introduces DUL service provided by Oracle ACS (of course the original field service is relatively expensive, and provided that the user has purchased the PS standards each year, otherwise you cannot even buy ACS Advanced Field Service):
DUL – DATA RECOVERY UNLOADER DataSheet
DUL 10 English version of user manual:
DUL User’s and Configuration Guide V10.2.4.27
The following is the download link DUL 10, but because of the lock, it will fail regularly.
DUL FOR LINUX platform (updated to PRM-DUL)
DUL FOR Windows platform (updated to PRM-DUL)
DUL can extracted data from a severely damaged database. DUL can directly scan Oracle Datafile, and identifies the header block segment header, have access to Extent information, and read data from the actual row. Then, it can generate import file in SQLLDR or DMP file in EXP.
If SYSTEM tablespace data files exist, DUL reads Oracle data dictionary. Otherwise DUL uses the form of actual read rows, and determines the field type and length depends on the internal algorithm.
DUL can basically process all of the common row types, including conventional row, migration row, chain row, multi Extents and clustered tables without additional manual intervention. Cross-platform extraction is also supported. DUL extract data directly from Oracle Datafile, without the need for Oracle database instance. It implements dirty reads , assuming that each transaction have already submitted. DUL does not detect whether to do media recovery, even damaged data block can also be read out. Support DMT and LMT table space. Because of its dirty reads, it is generally recommended to verify data by the application after DUL’s data recovery.
In terms of compatibility, DUL can process data filed copied from different operating systems. It supported most of the databases structure: chain row, migrate row, hash / index cluster, LONG, RAW, ROWID, DATE, Number, multi FreeList, high water level, NULL, and so on. DUL is compatible with ORACLE 6,7,8 and 9 and 10g 11g 12c.
Parnassusdata Software (where Maclean is) has developed similar products, PRM-DUL. The product is built on DUL and introduces graphical user interface GUI and DataBridge (data doesn’t need to be SQLLDR files, it can be directly transferred to the target database as DBLINK) and other functions on the basis of DUL; and because the PRM-DUL is written in JAVA, it can cover all platforms, including HP-UX.
PRM-DUL free version download:
http://www.parnassusdata.com/sites/default/files/ParnassusData%20Recover… 8B% E5% 86% 8C% 20v0.3.pdf
The free version of PRM-DUL, by default, can only extracts a million rows of data from each table. If your database is no more than ten thousand rows of data table, you can directly use the free PRM-DUL. If your database is large and contains important data, then you can consider buying the Enterprise Edition of PRM-DUL, PRM-DUL Enterprise provides a license for a set of databases. Each License costs 7500 yuan (including 17 %VAT).
Meanwhile PRM-DUL also provide some free License:
Free open several PRM-DUL Enterprise Edition License Key
If your Oracle database recovery case still fails after using DUL, you may consider the service recovery:
Parnassusdata Software now offers almost all Oracle recovery cases, including database does not open, the table was mistakenly DROP, TRUNCATE, DELETE, etc. ASM Diskgroup cannot MOUNT etc.