Waitopedia is a comprehensive resource of information about SQL Server waits.

The description shown below is the top answer as voted by the Spotlight community.

The charts are based on 2.1 TB of data collected from 4207 instances uploaded by 323 Spotlight users over an 8 week period.


Category: Other
SQL Server versions: 2012, 2014, 2016, 2017


1 Answer


Occurs during internal synchronization in metadata on table or index. Information from Microsoft®

Very rare

This wait never occurs for most instances

For each of 4207 instances, we ranked PWAIT_MD_RELATION_CACHE on how frequent it is compared to all other recent waits. The chart shows the total of all rankings.

Prevalence of PWAIT_MD_RELATION_CACHE across the Spotlight Population

For 34 % of hours with this wait, average wait time is less than 1.3 ms

For each instance, we found all the recent hours when it had a PWAIT_MD_RELATION_CACHE wait. We found the average latency for each of those hours.

46 instances contributed data to this chart

Latency Distribution of PWAIT_MD_RELATION_CACHE across the Spotlight Population