[CASSANDRA-11905] Index building fails to start CFS.readOrdering when reading

• Type: Bug
• Status: Resolved
• Priority: Urgent
• Resolution: Fixed
• Fix Version/s: 3.0.7, 3.6
• Severity: Critical
• Assignee: Sylvain Lebresne Assign to me
• Reporter: Sylvain Lebresne

Authors

Sylvain Lebresne

Reviewers

Stefania Alborghetti

• Created: 27/May/16 08:31
• Updated: 16/Apr/19 09:30
• Resolved: 30/May/16 14:18

Description

This code for indexing partition when building index in 3.0 is:

SinglePartitionReadCommand cmd = SinglePartitionReadCommand.fullPartitionRead(cfs.metadata, FBUtilities.nowInSeconds(), key);

try (OpOrder.Group opGroup = cfs.keyspace.writeOrder.start();
      UnfilteredRowIterator partition = cmd.queryMemtableAndDisk(cfs, opGroup))
{
    cfs.indexManager.indexPartition(partition, opGroup, indexes, cmd.nowInSec());
}

which is clearly incorrect as the OpOrder that queryMemtableAndDisk expects is the one from cfs.readOrdering, not the one for writes on the keyspace.
This wasn't a problem prior to 3.0 as the similar code was using the pager, which ended up properly taking the read OpOrder internally but I messed this up in CASSANDRA-8099.

Thanks to Stefania Alborghetti for pointing that out.