I have a user who has a copy of Oracle 9i on their PC. First thing after booting up, Queries run great. At end of day, very slow with lots of I/O wait. User claims to have not used Oracle all day when this occurs. Trace reveals a lot of I/O on system data file. Sys.seg$ seems to have 246,735 rows in it and query seems to be causing a full table scan of this table. User's SQL does not directly query this table, but is a union of two non system tables. Any ideas what would cause this?

-- John Alsup (jalsup@esri.com), November 17, 2004