9-2 IBM Informix OnLine Database Server Administrator’s Guide
Two-Phase Commit and Automatic Recovery ........ 9-23
Coordinator Recovery ...............9-23
Participant Recovery................ 9-26
Presumed-Abort Optimization ............9-29
Independent Action and Manual Recovery ......... 9-29
Heuristic Decisions: What and Why............ 9-30
Heuristic Rollback .................. 9-36
Condition 1: Logical Log Fills to a High-Water Mark..... 9-36
Condition 2: You Execute tbmode -z ..........9-37
When a Heuristic Rollback Occurs ........... 9-37
Heuristic End-Transaction ............... 9-40
Two-Phase Commit Protocol Errors............ 9-43
Two-Phase Commit and Logical Log Records ........ 9-44
BEGPREP ................... 9-44
PREPARE ...................9-44
TABLOCKS................... 9-45
HEURTX.................... 9-45
ENDTRANS .................. 9-45
Transaction Commit Records............. 9-46
Heuristic Rollback Records ............. 9-48
Heuristic End-Transaction Records........... 9-50
Determining Database Consistency ............ 9-51
Step 1: Determine Where a Heuristic Decision Occurred . . . 9-52
Step 2: Determine If the Networked Database Contains
Inconsistent Data .............. 9-53
Steps 3 and 4: Decide If Correction Is Needed ....... 9-54
Step 5: Use Logical Log Records............ 9-54
Example Manual Recovery ............. 9-55
IBM Informix STAR Configuration Parameters ........ 9-57
DEADLOCK TIMEOUT .............. 9-57
TXTIME-OUT .................. 9-58
Track a Transaction with tbstat Output........... 9-58
Tracking a Global Transaction ............ 9-59
Transaction address Field .............. 9-59
Transaction flag Field ............... 9-60
Transaction user Field ............... 9-61
Transaction locks Field ............... 9-61
Transaction log begin ............... 9-61
Transaction isolation Field.............. 9-62
Transaction retries Field .............. 9-62
Transaction coordinator Field.............9-62