PAGELATCH_UP

Overview

Occurs when waiting for an update latch on a buffer pool page in memory. The classic ‘last-page insert contention’ signal on index leaf pages — common on sequential identity columns and datetime clustered indexes.

Key Metrics

Metric	Description
Wait Type	PAGELATCH_UP
Category	Blocking
Severity	HIGH

Troubleshooting

1. Identify the source

Use the following query to identify the top queries contributing to PAGELATCH_UP waits:

SELECT TOP 10
 [Wait Type] = wait_type,
 [Wait Seconds] = wait_time_ms / 1000,
 [Wait Count] = waiting_tasks_count,
 [Avg Wait Ms] = wait_time_ms / NULLIF(waiting_tasks_count, 0)
FROM sys.dm_os_wait_stats
WHERE wait_type = 'PAGELATCH_UP'
ORDER BY wait_time_ms DESC;

2. Related diagnostics

• Review overall wait statistics using sys.dm_os_wait_stats
• Check session-level waits via sys.dm_exec_session_wait_stats
• Correlate with sys.dm_exec_requests for blocking analysis

See Also

• sys.dm_os_wait_stats (Transact-SQL)
• sys.dm_exec_session_wait_stats (Transact-SQL)
• sys.dm_os_waiting_tasks (Transact-SQL)