Database Backup   «Prev 

Direct Path Export in Oracle

Conventional Path Export Versus Direct Path Export

Export provides two methods for exporting table data:
  1. Conventional path Export
  2. Direct path Export
Conventional path Export uses the SQL SELECT statement to extract data from tables. Data is read from disk into a buffer cache, and rows are transferred to the evaluating buffer. The data, after passing expression evaluation, is transferred to the Export client, which then writes the data into the export file.
Direct path Export is much faster than conventional path Export because data is read from disk into the buffer cache and rows are transferred directly to the Export client. The evaluating buffer (that is, the SQL command-processing layer) is bypassed. The data is already in the format that Export expects, thus avoiding unnecessary data conversion. The data is transferred to the Export client, which then writes the data into the export file.

This is the start of a direct path export. Note the character set and the comment about exporting SYSTEM's tables via Direct Path.
This image contains a view of the tables being exported. Note the comment when exporting DEF$_AQCALL - this table can not be exported because it contains object or LOB data.
This image contains the non-table objects and indicates a successful completion of the export.