Contents
System Administration Guide xix
Using the reorg rebuild command on indexes.............................. 752
Syntax ................................................................................... 752
Comments............................................................................. 753
Limitations ............................................................................. 753
How indexes are rebuilt with reorg rebuild indexname.......... 754
Space requirements for rebuilding an index.......................... 755
Performance characteristics.................................................. 755
Status messages................................................................... 755
resume and time options for reorganizing large tables ................ 756
Specifying no_of_minutes in the time option......................... 756
CHAPTER 26 Checking Database Consistency .............................................. 759
What is the database consistency checker?................................ 759
Understanding page and object allocation concepts.................... 760
Understanding the object allocation map (OAM)................... 763
Understanding page linkage.................................................. 765
What checks can be performed with dbcc? ................................. 765
Checking consistency of databases and tables ........................... 766
dbcc checkstorage ................................................................ 767
dbcc checktable..................................................................... 770
dbcc checkdb ........................................................................ 772
Checking page allocation ............................................................. 772
dbcc checkalloc..................................................................... 773
dbcc indexalloc...................................................................... 774
dbcc tablealloc....................................................................... 775
Correcting allocation errors using the fix | nofix option................. 776
Generating reports with dbcc tablealloc and dbcc indexalloc ...... 776
Checking consistency of system tables ....................................... 777
Strategies for using consistency checking commands................. 778
Comparing the performance of dbcc commands .................. 778
Using large I/O and asynchronous prefetch.......................... 779
Scheduling database maintenance at your site..................... 779
Understanding the output from dbcc commands................... 782
Errors generated by database consistency problems ........... 783
Comparison of soft and hard faults ....................................... 784
Verifying faults with dbcc checkverify........................................... 785
How dbcc checkverify works ................................................. 785
When to use dbcc checkverify............................................... 786
How to use dbcc checkverify................................................. 788
Dropping a damaged database.................................................... 788
Preparing to use dbcc checkstorage............................................ 789
Planning resources................................................................ 790
Configuring Adaptive Server for dbcc checkstorage ............. 794
Creating the dbccdb database .............................................. 797