CMEMTHREAD

Overview

Occurs when waiting on a thread-safe memory allocation object. High values indicate memory object contention, often from frequent ad-hoc query compilations or parameterization inefficiencies.

Key Metrics

Metric	Description
Wait Type	CMEMTHREAD
Category	Memory
Severity	HIGH

Troubleshooting

1. Identify the source

Use the following query to identify the top queries contributing to CMEMTHREAD 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 = 'CMEMTHREAD'
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)