sa_diagnostic_blocking table

The sa_diagnostic_blocking table is owned by the dbo user, and records blocking events. If logging of blocking events is enabled, a row is inserted in this table each time a connection is blocked while trying to access a resource. Typically, this is caused by either a table or a row lock. A large number of blocks may indicate that you should examine the concurrency in your application to reduce contention for tables and rows.

There are two versions of this table: sa_diagnostic_blocking, and sa_tmp_diagnostic_blocking.

Columns

Column name	Column type	Column constraint	Table constraints
logging_session_id	UNSIGNED INT	NOT NULL	Foreign key references sa_diagnostic_cursor. Foreign key references sa_diagnostic_request.
lock_id	UNSIGNED BIGINT	NOT NULL
request_id	UNSIGNED BIGINT		Foreign key references sa_diagnostic_request.
cursor_id	UNSIGNED BIGINT		Foreign key references sa_diagnostic_cursor.
original_table_object_id	UNSIGNED BIGINT
rowid	UNSIGNED BIGINT
block_time	TIMESTAMP	NOT NULL
unblock_time	TIMESTAMP
blocked_by	UNSIGNED INT	NOT NULL

logging_session_id A number uniquely identifying the logging session during which the diagnostic information was gathered.

lock_id The ID of the lock that caused the blocking if a row or table lock caused the block, otherwise NULL.

request_id The ID of the request that was blocked if the block did not occur because of a cursor, otherwise NULL. This value corresponds to the ID assigned to the request in sa_diagnostic_request.

cursor_id The ID of the cursor if the block occurred because of a cursor, otherwise NULL. This value corresponds to the ID assigned to the cursor in sa_diagnostic_cursor.

original_table_object_id If the block occurred because of a table lock, the ID of the table on which the block occurred, otherwise NULL.

rowid If the block occurred because of a row lock, the ID of the row on which the block occurred, otherwise NULL.

block_time The time at which the block occurred.

unblock_time The time at which the block ended.

blocked_by The ID of the connection that held the lock, causing the block.

sa_diagnostic_blocking table

Columns

See also