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Updated on 2024-05-07 GMT+08:00

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GLOBAL_THREAD_WAIT_STATUS

In this view, you can check the blocking and waiting status of backend threads and auxiliary threads on all nodes. For details about events, see 15.3.67-Table 2 Waiting state list, 15.3.67-Table 3 List of wait events corresponding to lightweight locks, 15.3.67-Table 4 List of wait events corresponding to I/Os, and 15.3.67-Table 5 List of wait events corresponding to transaction locks.

In GLOBAL_THREAD_WAIT_STATUS, you can see all the call hierarchy relationships between threads of the SQL statements on all nodes in the database, and the block waiting status for each thread. With this view, you can easily locate the causes of process hang and similar issues.

The definitions of GLOBAL_THREAD_WAIT_STATUS and THREAD_WAIT_STATUS are the same, because the GLOBAL_THREAD_WAIT_STATUS view is essentially the query summary of the THREAD_WAIT_STATUS view on each node in the database.

**Table 1** GLOBAL_THREAD_WAIT_STATUS columns
Name	Type	Description
node_name	text	Database process name
db_name	text	Database name
thread_name	text	Thread name
query_id	bigint	Query ID. The value of this column is the same as that of debug_query_id.
tid	bigint	Thread ID of the current thread
sessionid	bigint	Session ID
lwtid	integer	Lightweight thread ID of the current thread
psessionid	bigint	Parent thread of the streaming thread
tlevel	integer	Level of the streaming thread
smpid	integer	Concurrent thread ID
wait_status	text	Waiting status of the current thread. For details about the waiting status, see Table 2.
wait_event	text	If wait_status is acquire lock, acquire lwlock, or wait io, this column describes the lock, lightweight lock, or I/O information. Otherwise, this column is empty.
locktag	text	Information about the lock that the current thread is waiting for
lockmode	text	Lock mode that the current thread is waiting to obtain The values include modes in the table-level lock, row-level lock, and page-level lock.
block_sessionid	bigint	ID of the session that blocks the current thread from obtaining the lock
global_sessionid	text	Global session ID