Page 178 - DCAP508_DATABASE_ADMINISTRATION

Database Administration

Notes PAG Data or index page.

EXT Contiguous group of eight data pages or index pages.
TAB Entire table, including all data and indexes.
DB Database.
Lock mode Shared (S) Used for operations that do not change or update data (read-
only operations), such as a SELECT statement.
Update (U) Used on resources that can be updated. Prevents a common
form of deadlock that occurs when multiple sessions are
reading, locking, and then potentially updating resources

later.

Exclusive (X) Used for data modification operations, such as UPDATE,
INSERT, or DELETE. Ensures that multiple updates cannot be

made to the same resource at the same time.

Intent Used to establish a lock hierarchy.

Schema Used when an operation dependent on the schema of a table is
executing. There are two types of schema locks: schema
stability (Sch-S) and schema modification (Sch-M).
Bulk update (BU) Used when bulk copying data into a table and the TABLOCK
hint is specified.
RangeS_S Shared range, shared resource lock; serializable range scan.
RangeS_U Shared range, update resource lock; serializable update scan.
RangeI_N Insert range, null resource lock. Used to test ranges before
inserting a new key into an index.
RangeX_X Exclusive range, exclusive resource lock. Used when updating
a key in a range.
Status GRANT Lock was obtained.
WAIT Lock is blocked by another process.

CNVT Lock is being converted to another lock. A lock being
converted to another lock is held in one mode but is waiting to
acquire a stronger lock mode (for example, update to
exclusive). When diagnosing blocking issues, a CNVT can be
considered similar to a WAIT.
Owner Owner The lock owner: xact (transaction), sess (session), or curs
(cursor).
Index Index The index associated with the resource. If the index is
clustered, you see the table name instead.
Resource RID Row identifier of the locked row within the table. The row is
identified by a fileid:page:rid combination, where rid is the
row identifier on the page.

KEY Hexadecimal number used internally by SQL Server.
PAG Page number. The page is identified by a fileid:page
combination, where fileid is the fileid in the sysfiles table,
and page is the logical page number within that file.
EXT First page number in the extent being locked. The page is
identified by a fileid:page combination.
TAB No information is provided because the ObjId column
already contains the object ID of the table.
DB No information is provided because the dbid column already

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