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https://issues.apache.org/jira/browse/CASSANDRA-14957?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16742861#comment-16742861
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Avraham Kalvo commented on CASSANDRA-14957:
-------------------------------------------
Thanks for the elaborated explanation [~VincentWhite],
Can you think of a condition where the above is experienced without an explicit
CREATE TABLE being issued? (mind you the table was there before the rolling
restart, and by the end of the rolling restart it became available with the new
version)
As all was done was merely to restart the nodes one by one, no CREATE TABLE
statements were issued throughout that restart whatsoever, The schema was
settled across all cluster eventually, as all of the nodes were restarted
consecutively.
Avi.
> Rolling Restart Of Nodes Causes Dataloss Due To Schema Collision
> ----------------------------------------------------------------
>
> Key: CASSANDRA-14957
> URL: https://issues.apache.org/jira/browse/CASSANDRA-14957
> Project: Cassandra
> Issue Type: Bug
> Components: Cluster/Schema
> Reporter: Avraham Kalvo
> Priority: Major
>
> We were issuing a rolling restart on a mission-critical five node C* cluster.
> The first node which was restarted got the following messages in its
> system.log:
> ```
> January 2nd 2019, 12:06:37.310 - INFO 12:06:35 Initializing
> tasks_scheduler_external.tasks
> ```
> ```
> WARN 12:06:39 UnknownColumnFamilyException reading from socket; closing
> org.apache.cassandra.db.UnknownColumnFamilyException: Couldn't find table for
> cfId bd7200a0-1567-11e8-8974-855d74ee356f. If a table was just created, this
> is likely due to the schema not being fully propagated. Please wait for
> schema agreement on table creation.
> at
> org.apache.cassandra.config.CFMetaData$Serializer.deserialize(CFMetaData.java:1336)
> ~[apache-cassandra-3.0.10.jar:3.0.10]
> at
> org.apache.cassandra.db.partitions.PartitionUpdate$PartitionUpdateSerializer.deserialize30(PartitionUpdate.java:660)
> ~[apache-cassandra-3.0.10.jar:3.0.10]
> at
> org.apache.cassandra.db.partitions.PartitionUpdate$PartitionUpdateSerializer.deserialize(PartitionUpdate.java:635)
> ~[apache-cassandra-3.0.10.jar:3.0.10]
> at
> org.apache.cassandra.db.Mutation$MutationSerializer.deserialize(Mutation.java:330)
> ~[apache-cassandra-3.0.10.jar:3.0.10]
> at
> org.apache.cassandra.db.Mutation$MutationSerializer.deserialize(Mutation.java:349)
> ~[apache-cassandra-3.0.10.jar:3.0.10]
> at
> org.apache.cassandra.db.Mutation$MutationSerializer.deserialize(Mutation.java:286)
> ~[apache-cassandra-3.0.10.jar:3.0.10]
> at org.apache.cassandra.net.MessageIn.read(MessageIn.java:98)
> ~[apache-cassandra-3.0.10.jar:3.0.10]
> at
> org.apache.cassandra.net.IncomingTcpConnection.receiveMessage(IncomingTcpConnection.java:201)
> ~[apache-cassandra-3.0.10.jar:3.0.10]
> at
> org.apache.cassandra.net.IncomingTcpConnection.receiveMessages(IncomingTcpConnection.java:178)
> ~[apache-cassandra-3.0.10.jar:3.0.10]
> at
> org.apache.cassandra.net.IncomingTcpConnection.run(IncomingTcpConnection.java:92)
> ~[apache-cassandra-3.0.10.jar:3.0.10]
> ```
> The latter was then repeated several times across the cluster.
> It was then found out that the table in question
> `tasks_scheduler_external.tasks` was created with a new schema version
> sometime along the entire cluster consecutive restart and became available
> once the schema agreement settled, which started taking requests leaving the
> previous version of the schema unavailable for any request, thus generating a
> data loss to our online system.
> Data loss was recovered by manually copying SSTables from the previous
> version directory of the schema to the new one followed by `nodetool refresh`
> to the relevant table.
> The above has repeated itself for several tables across various keyspaces.
> One other thing to mention is that a repair was in place for the first node
> to be restarted, which was obviously stopped as the daemon was shut down, but
> this doesn't seem to do with the above at first glance.
> Seems somewhat related to:
> https://issues.apache.org/jira/browse/CASSANDRA-13559
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