Michael Semb Wever created CASSANDRA-21658:
----------------------------------------------
Summary: A read on a replica that does not know the index yet
fails with a NullPointerException
Key: CASSANDRA-21658
URL: https://issues.apache.org/jira/browse/CASSANDRA-21658
Project: Apache Cassandra
Issue Type: Bug
Components: Feature/2i Index
Reporter: Michael Semb Wever
{{ReadCommand.Serializer.deserializeIndexMetadata}} returns null when the index
the coordinator names is unknown to this replica, and says so:
{code:java}
logger.info("Couldn't find a defined index on {}.{} with the id {}. " +
"If an index was just created, this is likely due to the schema not
" +
"being fully propagated. Local read will proceed without using the
" +
"index. ...");
return null;
{code}
The caller passes that null straight on:
{code:java}
IndexMetadata index = deserializeIndexMetadata(in, version, metadata);
Index.Group indexGroup =
Keyspace.openAndGetStore(metadata).indexManager.getIndexGroup(index);
{code}
{{SecondaryIndexManager.getIndexGroup}} calls {{getIndex}}, which reads
{{metadata.name}}, so the local read does not proceed at all: deserialization
throws a NullPointerException, the message is dropped, and the coordinator
waits for the read to time out. The window is the schema propagation of a new
index, so a client sees read timeouts for a short time after {{CREATE INDEX}}.
The patch tests the index metadata for null, so the read proceeds without the
index as the log line states, and marks {{deserializeIndexMetadata}}
{{Nullable}} together with the two {{SecondaryIndexManager}} methods that
require an index.
Patch:
[mck/upstream/read-command-unknown-index/5.0|https://github.com/thelastpickle/cassandra/tree/mck/upstream/read-command-unknown-index/5.0]
Provenance:
[69d5b5a300|https://github.com/datastax/cassandra/commit/69d5b5a300d2c82a83713191b4a8ed29c2dd5e04]
by Piotr Kołaczkowski, [~cassandra-te]. That commit is the same change; this
patch adds the regression test it lacks.
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