(8.4) PXC-4709: User is wrongly replicated to other nodes causing inconsistencies - #2160
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…encies https://perconadev.atlassian.net/browse/PXC-4709 Problem: Node is evicted from the cluster by inconsistency voting protocol. It happens when CREATE/ALTER USER is executed by the user without AUTHENTICATION_POLICY_ADMIN privilege. Cause: TOI is replicated before actual execution. On source node it fails, but on replicated node, it is executed by wsrep_applier thread working in root user context, so it doesn't fail remotely. It kicks-in inconsistency voting protocol which evicts the node from the cluster. Solution: On the Source side validate CREATE/ALTER USER against authentication policy before replicating. However, continue the normal flow, but skip TOI if validation fails. This is to keep original errors/warnings generated (and used for inconsistency voting). Eg. In case of policy violation and nonexistent plugin happening on the same time, we want ER_PLUGIN_IS_NOT_LOADED to be reported as the original flow does.
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dlenev
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Sep 23, 2025
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8.4 version of commit looks OK to me.
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https://perconadev.atlassian.net/browse/PXC-4709
Problem:
Node is evicted from the cluster by inconsistency voting protocol. It happens when CREATE/ALTER USER is executed by the user without AUTHENTICATION_POLICY_ADMIN privilege.
Cause:
TOI is replicated before actual execution. On source node it fails, but on replicated node, it is executed by wsrep_applier thread working in root user context, so it doesn't fail remotely. It kicks-in inconsistency voting protocol which evicts the node from the cluster.
Solution:
On the Source side validate CREATE/ALTER USER against authentication policy before replicating. However, continue the normal flow, but skip TOI if validation fails.
This is to keep original errors/warnings generated (and used for inconsistency voting). Eg. In case of policy violation and nonexistent plugin happening on the same time, we want ER_PLUGIN_IS_NOT_LOADED to be reported as the original flow does.