[SERVER-44076] Design synchronous trace logging for TLA+ Trace Checker Created: 17/Oct/19 Updated: 29/Oct/23 Resolved: 14/Nov/19 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | Replication |
| Affects Version/s: | None |
| Fix Version/s: | 4.3.2 |
| Type: | New Feature | Priority: | Major - P3 |
| Reporter: | A. Jesse Jiryu Davis | Assignee: | Judah Schvimer |
| Resolution: | Fixed | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Backwards Compatibility: | Fully Compatible |
| Sprint: | Repl 2019-11-04, Repl 2019-11-18 |
| Participants: |
| Description |
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When multiple mongods on one machine log events with different timestamps, do we really know in what order they executed these logging statements? If not, can we create a logging mode (enabled only in certain test suites) that provides this guarantee? Besides ensuring that all mongods use the same clock, also consider logging higher-precision timestamps. Note: there is also the problem of multiple mongods logging events with the same timestamp. We guess that if the timestamp is high-precision and the clock is shared among mongods, that events with the same timestamp can fairly be considered "concurrent". If several events have the same timestamp, then run the trace checker on the execution traces resulting from each possible ordering of the apparently simultaneous events, per Jard & Bochmann 1983 "An approach to testing specifications". |
| Comments |
| Comment by Githook User [ 29/Jan/20 ] | |||||||||
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Author: {'username': 'ajdavis', 'name': 'A. Jesse Jiryu Davis', 'email': 'jesse@mongodb.com'}Message: This is a combination of 6 commits. Revert " This reverts commit 88aaa47b815507e3ddd9a3a79f00d0eaca3ae071. Revert " This reverts commit e57438bd024d04f82dcbcbe68fe223b3f3aec838. Revert " This reverts commit f515d2ad5494e64c3be80189e7ea6bceaf267421. Revert " This reverts commit 744200de5f5667334457ee35abfa3747e2e26d55. Revert " This reverts commit eda99cf7ca668908e5eb0498845b0270265c44e7. Revert " This reverts commit a60ce00707f0ffdb5d2ec5c3a72993cc2b2d2978. delete mode 100644 jstests/replsets/tla_plus_trace_checking.js | |||||||||
| Comment by A. Jesse Jiryu Davis [ 03/Dec/19 ] | |||||||||
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I vote we don't support Windows on Evergreen for now. I think testing multiple platforms won't be likely to reveal the spec transcription errors we're looking for. | |||||||||
| Comment by Judah Schvimer [ 02/Dec/19 ] | |||||||||
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Do we need trace logging to work on Windows, or can we "comment" that away as unsupported? | |||||||||
| Comment by Mark Benvenuto [ 02/Dec/19 ] | |||||||||
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On Windows, it depends on the operating system. On Windows 8+, we rely on the OS to get high quality timestamps. On Windows 2008R2, we estimate a high quality timestamp. But in general, it can go backwards when synced with NTP. For more details, see the Windows docs on the scary details. | |||||||||
| Comment by A. Jesse Jiryu Davis [ 29/Nov/19 ] | |||||||||
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mark.benvenuto, we have a question for you, originally from suganthi.mani in a related code review forĀ We're trying to implement log messages with distinct timestamps in the simplest manner possible, only for certain tests in Evergreen. We've written this:
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| Comment by Githook User [ 14/Nov/19 ] | |||||||||
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Author: {'username': 'judahschvimer', 'email': 'judah.schvimer@10gen.com', 'name': 'Judah Schvimer'}Message: | |||||||||
| Comment by A. Jesse Jiryu Davis [ 04/Nov/19 ] | |||||||||
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Terrific. We'll be careful when reviewing the logging statements I add in |