I'm testing 10gR2 on a new Linux box. I decided to fiddle with enabling async IO. To test the async IO, I imported a table and I also ran several queries . I ran these tests one at a time (e.g. the queries and imports were not running simultaneously). I see NO performance difference for my import or queries with async IO enabled. I expected to see some performance difference (meaing change in elapsed time). Does async IO only help when you have multiple sessions performing IO simultaneously? Redhat Linux 2.6.9-5.ELsmp Oracle 10.2.0.1.0 I enabled async IO as follows: $cd $ORACLE_HOME/rdbms/lib $ln -s /usr/lib/libaio.so.1 skgaio.o $make PL_ORALIBS=-laio -f ins_rdbms.mk async_on filesystemio_options =asynch disk_asynch_io=true Stats change when I check slabinfo, so it appears as though async io is enabled: cat /proc/slabinfo | grep -e kio -e name As a side note, enabling the deadline scheduler DID reduce the time it took for an import (elevator=deadline in /etc/grub.conf). The import went from 26 minutes to 11 minutes. Thank you, Jay **DISCLAIMER This e-mail message and any files transmitted with it are intended for the use of the individual or entity to which they are addressed and may contain information that is privileged, proprietary and confidential. If you are not the intended recipient, you may not use, copy or disclose to anyone the message or any information contained in the message. If you have received this communication in error, please notify the sender and delete this e-mail message. The contents do not represent the opinion of D&E except to the extent that it relates to their official business.