The document discusses data unloading tools that can be used when a database is unavailable or corrupted. It describes a case study where a company's advertising database crashed, causing loss of revenue. A data unloader tool called DUDE was able to recover all the company's data within a few days. The document then explains how data unloading tools like DUDE work by bypassing the database engine and directly reading and parsing datafile blocks to extract data into flat files. It notes some of the challenges of using these tools and describes DUDE's capabilities for supporting multiple Oracle versions and platforms.
1. DUDE Where’s My Data..? 2008 User Conference Kugendran Naidoo
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10. Data Unloaders – Row Internals… Flag 1 byte Lock 1 byte # column Pieces 1 byte Rowheader for chained row in normal heap table Column header Column data # col pieces < # cols (ignore trailing nulls) Max 0xFF or 255 -> intra-block chaining RDBA 4 bytes Rowslot 2 bytes Address of block containing next rowpiece Rowdir index of next block
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14. Data Unloaders – DUDE Internals… SYSTEM TS AVAILABLE system obj$ tab$ col$ user$ lob$ part$ create dictionary ; obj$ tab$ col$ user$ lob$ part$ Dude Memory tools 1400 1444 1450 3029 USER_TABLENAME_OBJID.dmp 45003 55042 USER_TABLENAME_OBJID.dat USER_TABLENAME_OBJID.ctl USER_TABLENAME_OBJID.ddl
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