Run session token renewals in a database transaction#34379
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ChristophWurst merged 1 commit intomasterfrom Oct 18, 2022
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Run session token renewals in a database transaction#34379ChristophWurst merged 1 commit intomasterfrom
ChristophWurst merged 1 commit intomasterfrom
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ChristophWurst
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AndyScherzinger,
CarlSchwan,
PVince81,
juliusknorr and
nickvergessen
rullzer
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Oct 2, 2022
st3iny
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Oct 11, 2022
ChristophWurst
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AndyScherzinger
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Oct 11, 2022
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@ChristophWurst please fix for php-cs |
The session token renewal does 1) Read the old token 2) Write a new token 3) Delete the old token If two processes succeed to read the old token there can be two new tokens because the queries were not run in a transaction. This is particularly problematic on clustered DBs where 1) would go to a read node and 2) and 3) go to a write node. Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>
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@ChristophWurst @PVince81 how far back would we want to backport this? Asking since this might help with some large scale installations but might also hurt some in cases were long(er) running transactions might cause issues with raising the probability of deadlocks in a cluster setup. |
Member
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The used API exists since 24 |
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Author
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Wrapping these related queries in a query is one of the proposed solution we received from the mariadb experts. Write and delete will always run on the main database node. The transaction will only cause the read to happen on the same. I think this should be fine. |
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@ChristophWurst can you cover a backport to 24+ then? Thanks in advance 🙏 |
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/backport to stable25 |
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Author
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/backport to stable24 |
This was referenced Nov 3, 2022
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The session token renewal does
If two processes succeed to read the old token there can be two new tokens because the queries were not run in a transaction. This is particularly problematic on clustered DBs where 1) would go to a read node and 2) and 3) go to a write node.
Wrapping this code in a transaction makes sure that it all goes through or the insert/delete never happen, as it should.
This problem came up in a discussion with @rullzer.
This is best reviewed as https://github.com/nextcloud/server/pull/34379/files?w=1.