ctlog: test recover behavior with errors on overwrite #12
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Test recovery behavior when using conditional requests to upload immutable
files (using "If-Match" on Tigris).
A sequencing failure after uploading a tile but before updating the lock can
cause the log to get stuck:
- Sequencing starts.
- The sequencer writer tile file "A".
- The sequences fails to update the lock.
- Sequencing restarts.
- The sequencer tries to write tile file "A".
- The sequencer fails because tile file "A" already exists.
In the log this looks as follows:
testlog_test.go:79: time=2024-03-16T17:44:35.325-07:00 level=DEBUG source=ctlog.go:751 msg="uploading partial data tile" tree_size=1 tile="{H:8 L:-1 N:0 W:1}" size=25
testlog_test.go:79: time=2024-03-16T17:44:35.325-07:00 level=DEBUG source=ctlog.go:771 msg="uploading tree tile" old_tree_size=0 tree_size=1 tile="{H:8 L:0 N:0 W:1}" size=32
testlog_test.go:79: time=2024-03-16T17:44:35.325-07:00 level=DEBUG source=ctlog.go:795 msg="uploading checkpoint" size=209
testlog_test.go:79: time=2024-03-16T17:44:35.325-07:00 level=ERROR source=ctlog.go:671 msg="pool sequencing failed" old_tree_size=0 entries=1 err="fatal sequencing error\nfailing commit checkpoint for test"
...
testlog_test.go:79: time=2024-03-16T17:44:35.326-07:00 level=DEBUG source=ctlog.go:751 msg="uploading partial data tile" tree_size=1 tile="{H:8 L:-1 N:0 W:1}" size=32
testlog_test.go:79: time=2024-03-16T17:44:35.326-07:00 level=DEBUG source=ctlog.go:771 msg="uploading tree tile" old_tree_size=0 tree_size=1 tile="{H:8 L:0 N:0 W:1}" size=32
testlog_test.go:79: time=2024-03-16T17:44:35.326-07:00 level=ERROR source=ctlog.go:671 msg="pool sequencing failed" old_tree_size=0 entries=1 err="couldn't upload a tile: key \"tile/8/0/000.p/1\" already exists"
jellevandenhooff
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cristaloleg
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FiloSottile
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FiloSottile
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This can cause the log to lock up as describe in #12, or even in steady state due to request hedging: if request A wins, but request B returns a 412 before request A's 200, the sequencing will fail (safely) and leave behind non-overwritable tiles. This means the tree might suffer fatal failures on Tigris if two sequencers run at the same time, or if the stale Get issues in the LockBackend reoccur, since there is no object versioning.
FiloSottile
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Test recovery behavior when using conditional requests to upload immutable files (using "If-Match" on Tigris).
A sequencing failure after uploading a tile but before updating the lock can cause the log to get stuck:
In the log this looks as follows: