Interesting! Could it be a result of bad settings for the overflow segment (you have an overflow segment that requires a single block visits similar to the chained rows situation for tables)? Waleed -----Original Message----- From: Rick Stephenson [mailto:RStephenson@xxxxxxxx]=20 Sent: Wednesday, May 26, 2004 5:04 PM To: oracle-l@xxxxxxxxxxxxx Subject: Export of IOT very slow Why does an IOT only allow for 1 block read at a time to extract data during an export. I have an IOT with 250 Million rows that takes 24 hours to export, whereas, I have a heap table with 12 million rows that takes 6 minutes to export. If I extrapolate that out, the heap table would take roughly 2 hours to finish with 250 million rows. I decided to trace the processes and noticed that the IOT export will only read 1 block at a time, whereas the heap reads in 16 blocks at a time. Is there a way to force the "sequential" read to grab 16 blocks at a time? =20 I am running EE 9.2.0.3 on Solaris 2.8. =20 Trace file for IOT: WAIT #0: nam=3D'db file sequential read' ela=3D 5828 p1=3D15 p2=3D509603 = p3=3D1 WAIT #0: nam=3D'db file sequential read' ela=3D 16070 p1=3D17 = p2=3D1063439 p3=3D1 WAIT #0: nam=3D'db file sequential read' ela=3D 13220 p1=3D16 p2=3D39872 = p3=3D1 =20 Trace file for Heap: WAIT #3: nam=3D'db file scattered read' ela=3D 1810 p1=3D27 p2=3D32645 = p3=3D16 WAIT #3: nam=3D'db file scattered read' ela=3D 1648 p1=3D27 p2=3D32661 = p3=3D16 WAIT #3: nam=3D'db file scattered read' ela=3D 1866 p1=3D27 p2=3D32677 = p3=3D16 =20 Thanks for your help, =20 Rick Stephenson =20 ---------------------------------------------------------------- Please see the official ORACLE-L FAQ: http://www.orafaq.com ---------------------------------------------------------------- To unsubscribe send email to: oracle-l-request@xxxxxxxxxxxxx put 'unsubscribe' in the subject line. -- Archives are at //www.freelists.org/archives/oracle-l/ FAQ is at //www.freelists.org/help/fom-serve/cache/1.html ----------------------------------------------------------------- ---------------------------------------------------------------- Please see the official ORACLE-L FAQ: http://www.orafaq.com ---------------------------------------------------------------- To unsubscribe send email to: oracle-l-request@xxxxxxxxxxxxx put 'unsubscribe' in the subject line. -- Archives are at //www.freelists.org/archives/oracle-l/ FAQ is at //www.freelists.org/help/fom-serve/cache/1.html -----------------------------------------------------------------