Fault Analysis

The following table lists by type code the common faults that dbcc checkstorage reports, and shows the techniques you can use to further evaluate these faults. The most common approach is to use object level dbcc commands, such as dbcc checktable, to understand and further investigate checkstorage faults. Where the Action/Follow-up column lists multiple options, these appear in the order of most preferable option first. Where the Action/Follow-up column lists an error number, see the writeup for the error in Chapter 3, “Error Message Writeups” for details.

**Table 2-1: checkstorage fault analysis**
checkstorage Type Code	Fault Description	Action/Follow-up
100000	Disk read failed	Check Sybase device
100001	Page ID errors such as page number out of range	Similar to 2523 Error
100002	pfreeoff field on header page has an invalid value	Similar to 2505 Error
100003	1. Allocation page in wrong location or location of an allocation page contains something else 2. Object ID reference error	dbcc checktable, dbcc tablealloc, dbcc checkalloc Similar to 2529 Error dbcc checktable, dbcc tablealloc, dbcc checkalloc Similar to 1133, 2522, 2540 Errors
100006	Object allocation error	dbcc tablealloc Similar to 2522, 2525 Errors
100008	Incorrect page status bit in page header	dbcc checktable Similar to 7948 Error
100009	Column/row size error, or other row format error	dbcc checktable Similar to 2506, 2507, 2508 Errors
100010	Row location error	dbcc checktable Similar to 2509 Error
100014	Page referenced by more than one object	Similar to 2502 Error
100015	Page referenced more than once for an object	Similar to 2502 Error
100016	Page allocated but not linked	dbcc checktable Similar to 2540 Error
100017	Fault encountered on Object Allocation Map (OAM) page linkage	Similar to 2502 Error
100018	Allocation is not recorded in the Object Allocation Map (OAM)	dbcc indexalloc, dbcc tablealloc, dbcc checkalloc Similar to 7939 Error
100021	Fault encountered on last page of object chain	dbcc checktable Similar to 2575, 9924 Errors
100022	Fault encountered on first page of object chain	dbcc checktable Similar to 2577, 2578 Errors
100023	Object Allocation Map (OAM) count error	dbcc indexalloc, dbcc tablealloc, dbcc checkalloc Similar to 7940, 7949 Errors
100024	Object Allocation Map (OAM) count error	dbcc indexalloc, dbcc tablealloc, dbcc checkalloc Similar to 7940, 7949 Errors
100026	Serial allocation rule violation	Similar to 7989 Error
100027	Text chain has bad root page number	Similar to 2523 Error
100028	A page of the object was found in a location other than where allocations are currently allowed	Activate Trace Flag 2513 AND run: dbcc indexalloc, dbcc tablealloc, or dbcc checkalloc Similar to 2558 Error
100029	Control page: pprevpg or pnextpg non-zero	Similar to 2577 Error
100029	Data/text page: next page value non-zero on last page	dbcc checktable Similar to 2575 Error
100029	Data/text page: previous page value non-zero on first page	dbcc checktable Similar to 2578 Error
100031	Link check: referenced page is not allocated, or is allocated to a different object	dbcc tablealloc, dbcc checkalloc Similar to 2521, 2522 Errors
100032	Link check: pprevpg or pnextpg is inconsistent with page reference	Similar to 2503 Error
100033	Invalid or inconsistent value for the non-contiguous free space on the page.	reorg. Similar to 9988, 9993
100034	Invalid or inconsistent value for the contiguous free space on the page.	reorg. Similar to 9990, 9995
100035	Inconsistency in the page fullness indicator.	reorg. Similar to 12916.
100036	Invalid or inconsistent value for the deleted row count on the page.	reorg. Similar to 9989, 9994.
100037	Inconsistency between the forwarded rows indicator and the number of forwarded rows on the page.	reorg.
100038	Page header format indicator set incorrectly.	reorg; may require drop/recreate table.

The following checkstorage faults do not correspond to any existing dbcc errors:

**Table 2-2: **checkstorage** faults that do not map to **dbcc** errors**
checkstorage Type Code	Fault Description
100004	Pages with a timestamp in the future.
100005	Pages from the wrong database.
100007	Extent ID - pages allocated to a non-existent object. checkalloc with the fix option can correct this error.
100011	Text pointer - a corrupt text/image value for a table row/column. Look for other faults to determine the nature of the problem.
100012	Page status bits for the page show page type is different from the page chain being examined.
100019	Extra Object Allocation Map (OAM) Entry. Similar to 7940, 7949 Errors. checkalloc or tablealloc with the fix option can correct this error.
100025	Row count or rows per page error in Object Allocation Map (OAM). checktable corrects this error.
100029	1) index page only flag incorrectly set on a data page. Creating a clustered index or bulk copying data out and back in can correct this error. 2) poffset does not match the contents of the page. 3) plastrowoff is not the offset of the last row on an index page. 4) Out of range values in OAM page header fields. Many 100029 faults can be corrected by bulk copying data out and back in.
100030	Page formatting requirements for pages other than data and index. Checks depend on page type. OAM page: entries are for allocation pages and total of used+unused is less than 255. Control page: first or last page is invalid for database; the affinity table is corrupt. Text page: timestamps on the first page are invalid or inconsistent. Allocation page: extent on allocation page is not correctly allocated and is not free for allocation (similar to 2525 error).

checkstorage “soft” faults may or may not reflect actual corruption. Use dbcc checkverify to see if the faults are indeed hard errors.