Oracle High Performance Tuning for 9i and 10g

W

Wait Event Interface tuning, 647–94

bottlenecks, 647–49

Enterprise Manager, 665–69

health overview chart, 667

Top Objects and TopSQL, 668

improvements, 664–65

interface defined, 649–51

session layer, 656–62

event and wait event views, 657

hooking events to sessions, 661

SQL code for sessions, 662

system aggregation layer, 651–56

isolating segments, 654

third layer, 663–64

drilling down into latches, 663

tools used, 650

using STATSPACK, 669–93

Wait events, 575–609

definition, 575–76

idle events, 576–78

significant events, 578–609

automated undo waits, 603–5

buffer busy waits, 583–86

causes of buffer busy waits, 586–87

datafile scattered and sequential reads, 592–95

decreasing buffer busy waits, 587–92

direct path reads and writes, 595

enqueue waits, 605–8

examples of events, 578–83

free buffer waits, 595–96

latch free waits, 608–9

library cache waits, 597–98

manual rollback waits, 602–3

redo log waits, 598–602

row cache lock waits, 596

Windows Performance Monitor, 636–37