db file sequential read - again

I know this has been discussed here before....I have a small C++ program in a timer loop that spins around looking for the db file scattered read as well as the db file sequential read event and logs the segments to a table on the side. I've noticed that some of the 'sequential' read events have their P1 and P2 parameters referring to segments marked 'TABLE' in DBA_EXTENTS. I had always
thought the 'sequential' event referred to index blocks

• Can somebody re-explain this please?

Also ... what do db file sequential reads of block #0 of a datafile represent? This is 9.2.07 on AIX 5.3 (Asynch I/O enabled), all tablespaces are LMT. I'm assuming these single block reads of block 0 are for space management and therefore unavoidable?

Bonus question....this is a Siebel V7.5.3 db running in RULE mode with Indexes up the wahzoo. I'm seeing a lot of db file sequential read waits because RBO is
using any index it finds (which we all know could be a bad thing!). I'm thinking of putting hot indexes into their own buffer pool since I've got tons of memory. Does this sound like a reasonable approach to you folks?

Thanks in Advance!

Jeff H

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