[SERVER-29150] Oplog/Snapshot/Memory Created: 11/May/17 Updated: 12/May/17 Resolved: 12/May/17 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | Internal Code, Replication, Write Ops |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Improvement | Priority: | Major - P3 |
| Reporter: | deyukong | Assignee: | Unassigned |
| Resolution: | Done | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Participants: |
| Description |
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If allow readMajority, snapshotManager will be opened on mongo-wt or mongorocks. My question is: |
| Comments |
| Comment by deyukong [ 12/May/17 ] |
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thanks for your reply. |
| Comment by Eric Milkie [ 12/May/17 ] |
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Thanks for your report. Please note that SERVER project is for reporting bugs or feature suggestions for the MongoDB server. For MongoDB-developer related support discussion please post on the mongodb-dev group. A question like this involving more discussion would be best posted on the mongodb-dev group. |
| Comment by Eric Milkie [ 12/May/17 ] |
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In your scenario, as more writes happen, the WiredTiger cache will eventually fill up with update data. This data is then spilled to disk in a LAS (lookaside) file. While performance will suffer when this happens, it should not run out of memory. |
| Comment by Eric Milkie [ 12/May/17 ] |
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Named snapshots for the purposes of satisfying read-concern-majority are limited to 1000. There is an algorithm that controls this at https://github.com/mongodb/mongo/blob/3448ddb2ec7b3e210dfc97c0296dd7496f5c7813/src/mongo/db/repl/oplog.cpp#L1163 |