Well, Tim did say he was making a long story short.
scattered reads = multiblock reads which are typically associated with tablescans, but can be index fast full scans. sequential reads = single block reads which are typically associated with index block reads, table blocks accessed as a consequence of index block reads, but can be one-off blocks in table scans and index fast full scans due to the existence of previously buffered blocks or tail-end blocks on extents. And then there are cached LOB reads and .... Jonathan Lewis http://www.jlcomp.demon.co.uk Author of: Practical Oracle 8i: Building Efficient Databases Next Seminar - Australia - July/August http://www.jlcomp.demon.co.uk/seminar.html Host to The Co-Operative Oracle Users' FAQ http://www.jlcomp.demon.co.uk/faq/ind_faq.html -----Original Message----- To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> Date: 25 April 2002 00:21 |> "db file scattered read" (associated with FULL |> table scans) and "db file sequential |> read" (associated with indexed scans) | |But see, Tuning 101, p. 35, where a "db file sequential read" is |investigated and the waits are found to be reads from a *table*. | |And other examples elsewhere, where "db file scattered read" is found to be |associated with reads from an index. | -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Jonathan Lewis INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).