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11g Hang Detection

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Hang detection (cyclic, acyclic)? Test case builder. Health checks ... Database completely disabled but failure does not qualify as a hang. Prelim connection ... – PowerPoint PPT presentation

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Provided by: jeremia3
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Title: 11g Hang Detection


1
11g Hang Detection
  • Jeremiah Wilton
  • http//www.ora-600.net

2
11g Diagnosability Infrastructure
  • ADR / IPS (adrci, DIAG, dia0)?
  • Prelim connection (excellent)?
  • Hang detection (cyclic, acyclic)?
  • Test case builder
  • Health checks (on-demand, reactive)?
  • Interfaces to DB/Grid Control
  • Advisers (SQL Repair)?

3
Cyclic Hangs
  • Sessions deadlocked through chain of resources
  • Generates ORA-60 like normal deadlocks
  • Demo...

4
Acyclic Hangs
  • 11g harder to hang
  • Chains of resource holding
  • Steady (seconds_in_wait increasing)?
  • Takes min 300 seconds
  • RAC only
  • Quietly generates a trace file (no alert log
    message)?
  • ltSIDgt_DIA0_ltPIDgt_ltngt.trc
  • test01_DIA0_3867_1.trc
  • Message in DIA0 trace About to produce dumps
  • Demo

5
My hopes for hang detection
  • Amazon's model
  • Customizable / scriptable
  • When to dump
  • What to dump
  • Integrate with ADR

6
Real-world hangs
  • Hang with LC Pin pile-up (typical)?
  • Hang with BCT writer I/O hanging (bug?)?
  • Database completely disabled but failure does not
    qualify as a hang

7
Prelim connection
  • Can connect to a totally hung instance
  • Use your own or attach to an existing process
  • Hanganalyze, systemstate, errorstack
  • Run queries on x structs - results to screen or
    trace
  • Pull ASH data
  • Can you do prelim from non-SQLPlus?

8
Other data sourceswhen you can log in
  • ASH your first stop for performance
  • Hanganalyze
  • Errorstack

9
Talk back
  • We need to report typical events to Oracle
  • Support is a sufficient route (enhancement
    request)?
  • Bring them good data
  • Tell me or use your sales channels to get it on
    the agenda
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