[SERVER-3433] Command to report %-in memory per namespace Created: 15/Jul/11 Updated: 06/Dec/22 Resolved: 18/Dec/18 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | Admin, Performance |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | New Feature | Priority: | Major - P3 |
| Reporter: | Scott Hernandez (Inactive) | Assignee: | Backlog - Storage Execution Team |
| Resolution: | Won't Fix | Votes: | 4 |
| Labels: | caching, memory, mincore | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
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| Assigned Teams: |
Storage Execution
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| Description |
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Add a command which can report the % of the namespace (for both the data and all indexes related to a collection) which is currently in (mapped-resident/cache) memory. This can be added for reporting cache/memory efficiency and for debugging performance issues. It could be called something like {cacheStats: <ns>} and report something like this: Where percent is the percent in memory of the namespace, and a graphic (textual) representation shows which parts of the namespace are in memory. Or a distribution is the number of the contiguous page blocks (which could tell you if you are accessing data randomly or in ranges, and should be cheap to calculate as you are walking pages ~ mincore). |
| Comments |
| Comment by Adam Flynn [ 14/Dec/12 ] |
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We built a tool to do something like this. Doesn't give distribution within a collection, but it'll tell you how much of each collection is currently in cache. http://eng.wish.com/mongomem-memory-usage-by-collection-in-mongodb/ |
| Comment by Grégoire Seux [ 15/Oct/12 ] |
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this would be great to understand the reason of page faults |