7-36 IBM Informix OnLine Database Server Administrator’s Guide

tbcheck: Check, Repair, or Display

tbcheck: Check, Repair, or Display
Depending on the options you choose,tbcheck can do the following things:
■Check specified structures for inconsistencies
■Repair index structures found to contain inconsistencies
■Display information about the structures
The only structures thattbcheck can repair are indexes. If tbcheck detects
inconsistencies in other structures, messages alert you to these inconsis-
tencies buttbcheck cannot resolve the problem. For more details about
OnLine consistency checking and dealing with corruption, refer topage 4-6.
Any user can execute the check options. Only userinformix or root can
display database data or initiate index repairs. OnLine must be in quiescent
mode to repair indexes.
The display options of thetbcheck utility can be compared to the tbstat
utility, which also displays information about OnLine structures. Thetbstat
utility reads the shared-memory segment and reports statistics that are
accurate for the instant during which the command executes. That is,tbstat
describes information that changes dynamically during processing, such as
buffers, locks, and users. Thetbcheck utility tends to display configuration
and disk-usage information that is read directly from the disk and that
changes less frequently.
The list below associatestbcheck options with their function. Syntax is
providedon page 7-38. Some display options also perform checking. Refer to
the descriptions that begin onpage 7-39 for details.
Check Repair Display
Blobspace blobs -pB
Chunks and extents -ce -pe
Data rows, no blobs -cd -pd
Data rows, blob pages -cD -pD
Index (key values) -ci -ci -y, -pk -y -pk
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