■ CONTENTS
xiv
Parameter READ_ONLY_OPEN_DELAYED............................................................................................. 367
Summary ................................................................................................................................................... 367
■Chapter 11: Statistics ..........................................................................................369
It Can’t Be Done!........................................................................................................................................ 369
Subquery Anomaly................................................................................................................................ 370
Partition Elimination ............................................................................................................................. 374
Lack of Knowledge .................................................................................................................................... 378
Problems with Statistics............................................................................................................................ 385
Timing........................................................................................................................................................ 387
Multinationals....................................................................................................................................... 387
Partitioning ........................................................................................................................................... 387
Batch Jobs............................................................................................................................................ 388
Creating Statistics ..................................................................................................................................... 388
Other Stats............................................................................................................................................ 394
Baseline................................................................................................................................................ 396
Summary ................................................................................................................................................... 397
■Chapter 12: Troubleshooting Latch Contention ...................................................399
Latches and Why We Need Them.............................................................................................................. 399
Solitaire, Parent, and Child Latches .......................................................................................................... 400
Operational Specifics................................................................................................................................. 401
Immediate Mode................................................................................................................................... 401
Willing-to-Wait Mode............................................................................................................................ 403
Latch-Wait Posting Mode ..................................................................................................................... 404
Identifying and Analyzing Latch Contention .............................................................................................. 404
Step 1: Identify Latches Causing Contention........................................................................................ 404
Step 2: Review Distribution of Gets...................................................................................................... 406
Step 3: Check the Code Path................................................................................................................ 406
Cache Buffers Chains Latch Contention .................................................................................................... 407
Common Causes of CBC Latch Contention........................................................................................... 409