dbcc_types

Description

The dbcc_types table provides the definitions of the data types used by dbcc checkstorage. This table is not actually used by the dbcc stored procedures. It is provided to facilitate the use of the other tables in dbccdb, and to document the semantics of the data types. Type codes for operation configuration, analysis data reported, fault classification, and fault report parameters are included. If you create your own stored procedures for generating reports, the values listed in the type_name column can be used as report headings.

Columns

The columns for dbcc_types are as follows.

To allow for future additions to dbcc_types, some type_code numbers are not used at this time:

**Table 13-1: dbcc Types**
type_code	type_name	Description
1	max worker processes	Optional – Specifies the maximum number of worker processes that can be employed. This is also the maximum level of concurrent processing used. Minimum value is 1.
2	dbcc named cache	Specifies the size (in kilobytes) of the cache used by dbcc checkstorage and the name of that cache.
3	scan workspace	Specifies the ID and name of the workspace to be used by the database scan.
4	text workspace	Specifies the ID and name of the workspace to be used for text columns.
5	operation sequence number	Specifies the number that identifies the dbcc operation that was started most recently.
6	database name	Specifies the name of the database in sysdatabases.
7	OAM count threshold	Specifies the percentage by which the OAM counts must vary before they can be considered to be an error.
8	IO error abort	Specifies the number of I/O errors allowed on a disk before dbcc stops checking the pages on that disk.
9	linkage error abort	Specifies the number of linkage errors allowed before dbcc stops checking the page chains of an object. Some kinds of page chain corruptions might require a check to be stopped with fewer linkage error than other kinds of page chain corruptions.
1000	hard fault count	Specifies the number of persistent inconsistencies (hard faults) found during the consistency check.
1001	soft fault count	Specifies the number of suspect conditions (soft faults) found during the consistency check.
1002	checks aborted count	Specifies the number of linkage checks that were stopped during the consistency check.
1007	text column count	Specifies the number of non-null text/image column values found during the consistency check.
5000	bytes data	Specifies (in bytes) the amount of user data stored in the partition being checked.
5001	bytes used	Specifies (in bytes) the amount of storage used to record the data in the partition being checked. The difference between bytes used and bytes data shows the amount of overhead needed to store or index the data.
5002	pages used	Specifies the number of pages linked to the object being checked that are actually used to hold the object.
5003	pages reserved	Specifies the number of pages that are reserved for the object being checked, but that are not allocated for use by that object. The difference between (8 * extents used) and (pages used + pages reserved) shows the total uncommitted deallocations and pages incorrectly allocated.
5004	pages overhead	Specifies the number of pages used for the overhead functions such as OAM pages or index statistics.
5005	extents used	Specifies the number of extents allocated to the object in the partition being checked. For object 99 (allocation pages), this value is the number of extents that are not allocated to a valid object. Object 99 contains the storage that is not allocated to other objects.
5006	count	Specifies the number of component items (rows or keys) found on any page in the part of the object being checked.
5007	max count	Specifies the maximum number of component items found on any page in the part of the object being checked.
5008	max size	Specifies the maximum size of any component item found on any page in the part of the object being checked.
5009	max level	Specifies the maximum number of levels in an index. This datatype is not applicable to tables.
5010	pages misallocated	Specifies the number of pages that are allocated to the object, but are not initialized correctly. It is a fault counter.
5011	io errors	Specifies the number of I/O errors encountered. This datatype is a fault counter.
5012	page format errors	Specifies the number of page format errors reported. This datatype is a fault counter.
5013	pages not allocated	Specifies the number of pages linked to the object through its chain, but not allocated. This datatype is a fault counter.
5014	pages not referenced	Specifies the number of pages allocated to the object, but not reached through its chains. This datatype is a fault counter.
5015	overflow pages	Specifies the number of overflow pages encountered. This datatype is only applicable to clustered indexes.
5016	page gaps	Specifies the number of pages not linked to the next page in ascending sequence. This number indicates the amount of table fragmentation.
5017	page extent crosses	Specifies the number of pages that are linked to pages outside of their own extent. As the number of page extent crosses increases relative to pages used or extents used, the effectiveness of large I/O buffers decreases.
5018	page extent gaps	Specifies the number of page extent crosses where the subsequent extent is not the next extent in ascending sequence. Maximal I/O performance on a full scan is achieved when the number of page extent gaps is minimized. A seek or full disk rotation is likely for each gap.
5019	ws buffer crosses	Specifies the number of pages that are linked outside of their workspace buffer cache during the dbcc checkstorage operation. This information can be used to size the cache, which provides high performance without wasting resources.
5020	deleted rows	Deleted rows, the number of deleted rows in the object
5021	forwarded rows	Forwarded rows, number of forwarded rows in the object
5022	empty pages	The number of pages allocated but not containing data
5023	pages with garbage	Pages with garbage, number of pages that could benefit from garbage collection
5024	non-contiguous free space.	Non-contiguous free space, number of bytes of non-contiguous free space
10000	page id	Specifies the location in the database of the page that was being checked when the fault was detected. All localized faults include this parameter.
10001	page header	Specifies the hexadecimal representation of the header of the page that was being checked when the fault was detected. This information is useful for evaluating soft faults and for determining if the page has been updated since it was checked. The server truncates trailing zeros.
10002	text column id	Specifies an 8-byte hexadecimal value that gives the page, row, and column of the reference to a text chain that had a fault. The server truncates trailing zeros.
10003	object id	Specifies a 9-byte hexadecimal value that provides the object id (table), the partition id (partition of the table) if applicable, and the index id (index) of the page or allocation being checked. For example, if a page is expected to belong to table T1 because it is reached from T1’s chain, but is actually allocated to table T2, the object id for T1 is recorded, and the object id expected for T2 is recorded. The server truncates trailing zeros.
10007	page id expected	Specifies the page ID that is expected for the linked page when there is a discrepancy between the page ID that is expected and the page ID that is actually encountered. For example, if you follow the chain from P1 to P2 when going forward, then, when going backward, P1 is expected to come after P2. The value of page id expected is P1, and the value of page id is P2. When the actual value of P3 is encountered, it is recorded as page id actual.
10008	page id actual	When there is a discrepancy between the page ID that is encountered and the expected page ID, this value specifies the actual page ID that is encountered. (See also, type_code 10007.) For example, if you follow the chain from P1 to P2 when going forward, then, when going backward, P1 is expected to come after P2. The value of page id expected is P1, and the value of page id is P2. When the actual value of P3 is encountered, it is recorded as page id actual.
10009	object id expected	Specifies a 9-byte hexadecimal value that provides the expected object id (table), the partition id (partition of the table) if applicable, and the index id (index) of the page or allocation being checked. For example, if a page is expected to belong to table T1 because it is reached from T1’s chain, but is actually allocated to table T2, the object id for T1 is recorded, and the object id expected for T2 is recorded. The server truncates trailing zeros.
10010	data-only locked data page header	Indicates the 44 byte page header for the page where the fault is located
10011	data-only locked b-tree leaf page header	Indicates the 44 byte page header for the page where the fault is located
10012	data-only locked b-tree header	Indicates the 44 byte page header for the page where the fault is located
100000	IO error	Indicates that part of the identified page could not be fetched from the device. This is usually caused by a failure of the operating system or the hardware.
100001	page id error	Indicates that the identifying ID (page number) recorded on the page is not valid. This might be the result of a page being written to or read from the wrong disk location, corruption of a page either before or as it is being written, or allocation of a page without subsequent initialization of that page.
100002	page free offset error	Indicates that the end of data on a page is not valid. This event affects insertions and updates on this page. It might affect some access to the data on this page.
100003	page object id error	Indicates that the page appears to be allocated to some other table than the one expected. If this is a persistent fault, it might be the consequence of either: An incorrect page allocation, which might only result in the effective loss of this page to subsequent allocation, or A corrupted page chain, which might prevent access to the data in the corrupted chain
100004	timestamp error	Indicates that the page has a timestamp that is later than the database timestamp. This error can result in failure to recover when changes are made to this page.
100005	wrong dbid error	Indicates that the database ID dbid is stored on the database allocation pages. When this ID is incorrect, the allocation page is corrupt and all the indicated allocations are suspect.
100006	wrong object error	Indicates that the page allocation is inconsistent. The page appears to belong to one table or index, but it is recorded as being allocated to some other table or index in the allocation page. This error differs from page object id error in that the allocation is inconsistent, but the consequences are similar.
100007	extent id error	Indicates that an allocation was found for a table or index that is unknown to dbcc checkstorage. Typically, this results in the inability to use the allocated storage.
100008	fixed format error	Indicates that the page incorrectly indicates that it contains only rows of a single fixed length. dbcc checkstorage reports this error. dbcc checktable does not report it, but does repair it.
100009	row format error	Indicates that at least one row on the page is incorrectly formatted. This error might cause loss of access to some or all the data on this page.
100010	row offset error	Indicates that at least one row on the page is not located at the expected page offset. This error might cause loss of access to some or all of the data on this page.
100011	text pointer error	Indicates that the location of the table row that points to the corrupted text or image data. This information might be useful for correcting the problem.
100012	wrong type error	Indicates that the page has the wrong format. For example, a data page was found in an index or a text/image column.
100013	non-OAM error	This error is a special case of wrong type error. It is not reported as a separate condition in the current release.
100014	reused page error	Indicates that a page is reached by more than one chain and that the chains belong to different objects. This error indicates illegal sharing of a page through corrupt page chain linkages. Access to data in either or both tables might be affected.
100015	page loop error	Indicates that a page is reached a second time while following the page chain for an object, which indicates a loop in the page chain. A loop can result in a session hanging indefinitely while accessing data in that object.
100016	OAM ring error	Indicates that a page is allocated but not reached by the page chains for the object.Typically, this results in the inability to use the allocated storage.
100017	OAM ring error	Indicates that the OAM page ring linkages are corrupted. This might not affect access to the data for this object, but it might affect insertions, deletions, and updates to that data.
100018	missing OAM error	Indicates that dbcc checkstorage found an allocation for the object that was not recorded in the OAM. This error indicates a corruption that might affect future allocations of storage, but probably does not affect access to the presently stored data.
100019	extra OAM error	Indicates that an allocation for this object was recorded in the OAM, but it was not verified in the allocation page. This error indicates a corruption that might affect future allocations of storage, but probably does not affect access to the presently stored data.
100020	check aborted error	Indicates that dbcc checkstorage stopped checking the table or index. To prevent multiple fault reports, the check operation on a single chain might be stopped without reporting this error. When an object contains several page chains, failure of the check operation for one chain does not prevent the continuation of the check operation on the other chains unless a fault threshold is exceeded.
100021	chain end error	Indicates that the end of the chain is corrupted. As a soft fault, it might indicate only that the chain was extended or truncated by more than a few pages during the dbcc checkstorage operation.
100022	chain start error	Indicates that the start of a chain is corrupted or is not at the expected location. If this is a persistent fault, access to data stored in the object is probably affected.
100023	used count error	Indicates an inconsistency between the count of the pages used that is recorded in the OAM page and the count of the pages used that is determined by examining the allocation pages.
100024	unused count error	Indicates an inconsistency between the count of the pages reserved but unused that is recorded in the OAM page and the count of the pages reserved but unused that is determined by examining the allocation pages.
100025	row count error	Indicates an inconsistency between the row count recorded in the OAM page and the row count determined by dbcc checkstorage.
100026	serialloc error	Indicates a violation of the serial allocation rules applied to log allocations.
100027	text root error	Indicates a violation of the format of the root page of a text or image index. This check is similar to the root page checks performed by dbcc textalloc.
100028	page misplaced	Indicates that pages of this object were not found where they were expected to be from examination of the system tables. This usually indicates that sp_placeobject was used sometime in the past. In the dbcc_counters table, all misplaced pages are counted together, rather than being reported by device and partition.
100029	page header error	Indicates an internal inconsistency in the page’s header other than the kind described by the other type codes. The severity of this error depends on the type of page and the inconsistency found.
100030	page format error	Indicates an internal inconsistency in the page’s body other than the kind described by the other type codes. The severity of this error depends on the type of page and the inconsistency found.
100031	page not allocated	Indicates that dbcc checkstorage reached an unallocated page by following a page chain. This condition might affect access to data stored in this object.
100032	page linkage error	Indicates that dbcc checkstorage detected a fault with either the next or previous linkage of an interior page of a chain. If this is a persistent fault, access to data stored in the object is probably affected.
100033	non-contiguous free-space error	Indicates an invalid or inconsistent value for the non-contiguous free space on the page
100034	insert free space error	Indicates an invalid or inconsistent value for the contiguous free space on the page
100035	spacebits mismatch	Indicates an inconsistency in the page fullness indicator
100036	deleted row count error	Indicates an invalid or inconsistent value for the deleted row count on the page
100037	Forwarded rows error	Indicates an inconsistency between the forwarded rows indicator and the number of forwarded rows on the page
100038	Page header type error	Indicates that a Page header format indicator set incorrectly