Example:
Error in the Data Structure 
A base table contains a defective data page on the leaf level of the B* tree of the base table: leaf number 44690 with block address 1/564.
During a check of the database structure, the database system notices that the checksum for the data page is incorrect. The database system writes the following information in the kernel log (see Log Files):
● Error in the checksum
● Page number with data volume and block address information.
● Page number in the B* tree
● Type of the database object represented by the B* tree
● Root page of the B* tree
● Error message
Then the database system internally marks the database object as BAD.
Excerpt from the Kernel Log
2005-04-08 09:40:28 0xCEC ERR 4 Data Data_BasePage.cpp:124
2005-04-08 09:40:28 0xCEC ERR 4 Data 2005-04-08 09:40:28 AM Data Error 4
2005-04-08 09:40:28 0xCEC ERR 4 Data Checksum mismatch; calculated: 5468846 found: 22246062
2005-04-08 09:40:28 0xCEC ERR 25 IOMan IOMan_Volume.cpp:500
2005-04-08 09:40:28 0xCEC ERR 25 IOMan 2005-04-08 09:40:28 AM IOMan Error 25
2005-04-08 09:40:28 0xCEC ERR 25 IOMan Bad page on Data volume 1 blockno 564
2005-04-08 09:40:30 0xCEC ERR 36 IOMan IOMan_Manager.cpp:1007
2005-04-08 09:40:30 0xCEC ERR 36 IOMan 2005-04-08 09:40:30 AM IOMan Error 36
2005-04-08 09:40:30 0xCEC ERR 36 IOMan Bad data page 44690
2005-04-08 09:40:30 0xCEC ERR 18 Data vbd13.cpp:2426
2005-04-08 09:40:30 0xCEC ERR 18 Data 2005-04-08 09:40:30 AM Data Error 18
2005-04-08 09:40:30 0xCEC ERR 18 Data Bad data page 44690 of filetype 'Table' identified by root 104236
2005-04-08 09:40:30 0xCEC ERR 53021 B*TREE Bad File: 104236 (Root)
2005-04-08 09:40:30 0xCEC ERR 53000 B*TREE 0D000000000000000388000000000000
2005-04-08 09:40:30 0xCEC ERR 53000 B*TREE Table Root 104236
2005-04-08 09:40:30 0x37C ERR 53019 CHECK Base error: bad_datapage
2005-04-08 09:40:30 0x37C ERR 53019 CHECK Root pageNo: 104236
See also: