RE: Performance Question - High I/O per Insert
- From: "Mark Strickland" <mstrickland@xxxxxxxxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Tue, 28 Sep 2004 12:27:28 -0700
This is a follow-up to a question I posed earlier, but I have more info.
A SQL*Loader conventional path load inserts rows into a table
partitioned by week. On the first day of a new week, the load runs as
efficiently as expected, but as the week goes on, the load goes more and
more slowly. There is a single local index on each partition and the
blevel is 2. I'm scratching my head. I realize I'm not providing much
info, but can anyone tell me why loading into a partition might get
slower as the partition fills? Thx!
Mark Strickland
________________________________
From: Mark Strickland
Sent: Wednesday, September 22, 2004 12:42 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: Performance Question - High I/O per Insert
I'm trying to understand why I'm seeing a high number of I/Os for
inserts. Inserts are through SQL*Loader conventional patch. Average
row length is 129 bytes, no longs or blobs. The table has five indexes
and each index has a blevel of 2. According to v$sqlarea, each insert
uses 650 logical I/Os, 69 physical I/Os. I would expect fewer than 20
I/Os per insert. There are db file sequential read waits on the data
files that make up the index tablespace. That file system also contains
the archived logs. Not surprised at the contention. Can someone point
me in the right direction to understand this? Thx.
Mark Strickland
Drugstore.com
Seattle, WA
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