[MCOL-5163] Increase the stability of writing processes: WriteEngineServer, DMLProc, DDLProc Created: 2022-07-19 Updated: 2022-10-25 Resolved: 2022-08-19 |
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| Status: | Closed |
| Project: | MariaDB ColumnStore |
| Component/s: | DDLProc, DMLProc, writeengine |
| Affects Version/s: | 6.4.1 |
| Fix Version/s: | 22.08.1 |
| Type: | New Feature | Priority: | Major |
| Reporter: | Roman | Assignee: | Daniel Lee (Inactive) |
| Resolution: | Fixed | Votes: | 0 |
| Labels: | None | ||
| Issue Links: |
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| Sprint: | 2021-17 | ||||||||||||
| Description |
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As of 6.4.1 MCS uses systemd to handle processing start and stop routine. It also handles the processes hierarchy restarts, e.g. if mcs-primproc(contains both EM and PP) crashes systemd restarts mcs-writeengineserver unit. If WE is in the middle of a write operation this potentially left the system in an unusable state. If mcs-writeengineserver is restarted systemd restarts both mcs-dmlproc and mcs-ddlproc so if DMLProc was doing some changes it left failed transactions behind. It is tedious to clean these stuck txns from the cluster. |
| Comments |
| Comment by Roman [ 2022-08-16 ] |
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4QA Try to crash ExeMgr or PP and it will force WE and DMLProc to restart even if they are in the middle of a txn. The current version doesn't restart WE or DMLProc if PP has crashed. |
| Comment by Daniel Lee (Inactive) [ 2022-08-19 ] |
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Build verified: 22.08-1 (#5324) Also verified 6.x (#5262) since it was also checked into develop-6. |