[MCOL-3745] Investigate slow-down in DDL after a restart Created: 2020-01-27 Updated: 2020-03-13 Resolved: 2020-02-28 |
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| Status: | Closed |
| Project: | MariaDB ColumnStore |
| Component/s: | Storage Manager |
| Affects Version/s: | 1.4.2 |
| Fix Version/s: | 1.4.3 |
| Type: | Task | Priority: | Major |
| Reporter: | Todd Stoffel | Assignee: | Patrick LeBlanc (Inactive) |
| Resolution: | Fixed | Votes: | 0 |
| Labels: | None | ||
| Environment: |
Sky docker image |
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| Issue Links: |
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| Sprint: | 2020-1, 2020-2, 2020-3 | ||||||||
| Description |
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Todd noticed during testing that if he killed either controllernode or DMLProc, and let it restart, drop table would be occasionally be slow. Ben reproduced the problem and saw correlation with upstream bandwidth usage. When upstream traffic stops, that's when the drop table stmt would return. Ben also couldn't reproduce it when using the 'fake cloud' module. Need to investigate. |
| Comments |
| Comment by Patrick LeBlanc (Inactive) [ 2020-01-31 ] |
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Yes it's contention on a few hot files that get changed on many ops like in this sequence. Access to the BRM files, and the syscat files is blocked while they are being sync'd to cloud storage. On home networks with limited upstream that could be quite a while. For now I'll add documentation to relevant parameters in the config file to reduce the observed latency. I'll add a ticket to try to avoid locking files during network xfers. |
| Comment by Patrick LeBlanc (Inactive) [ 2020-02-03 ] |
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The intermediate fix for this is documentation in the config file. |
| Comment by Patrick LeBlanc (Inactive) [ 2020-02-28 ] |
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It was merged some time ago. |