[CASSANDRA-14462] CAS temporarily broken on reversed tables after upgrading on 2.1.X or 2.2.X

• Type: Bug
• Status: Open
• Priority: Normal
• Resolution: Unresolved
• Component/s: Legacy/Core
• Severity: Normal
• Assignee: Fabien Rousseau
• Reporter: Fabien Rousseau

Authors

Fabien Rousseau

• Created: 22/May/18 11:48
• Updated: 16/Apr/19 09:29

Description

Issue CASSANDRA-12127 changed the way the reversed comparator behaves. Before scrubbing tables with reversed clustering keys, requests with CAS won't apply (even if the condition is true).

Below is a simple scenario to reproduce it:

• use C* 2.1.14/2.2.6
• create the schema

  CREATE KEYSPACE IF NOT EXISTS test_ks WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 1};
  USE test_ks;
  CREATE TABLE IF NOT EXISTS test_cf (
   pid text,
   total int static,
   sid uuid,
   amount int,
   PRIMARY KEY ((pid), sid)
  ) WITH CLUSTERING ORDER BY (sid DESC);
  

   

• insert data

  INSERT INTO test_cf (pid, sid, amount) VALUES ('1', b2495ad2-9b64-4aab-b000-2ed20dda60ab, 2);
  INSERT INTO test_cf (pid, total) VALUES ('1', 2);

   

• nodetool flush (this is necessary for the scenario to show the problem)

• upgrade to C* 2.1.20/2.2.12
• execute the following queries:

  UPDATE test_cf SET total = 3 WHERE pid = '1' IF total = 2;
  UPDATE test_cf SET amount = 3 WHERE pid = '1' AND sid = b2495ad2-9b64-4aab-b000-2ed20dda60ab IF amount = 2;

   

Both statements won't be applied while they should be applied.

It seems related to the min/maxColumn sstable checks (before the scrubbing, the min is an empty array, after it is no more) which filter too many sstables.

The SliceQueryFilter.shouldInclude method filter too many SSTables.

Note: When doing a simple "SELECT total FROM test_cf WHERE pid ='1';" works well because the selected slices are different (and thus do not filter the sstables).

Note: This does not seem to affect the 3.0.X versions

Issue Links

• is related to: CASSANDRA-12127 Queries with empty ByteBuffer values in clustering column restrictions fail for non-composite compact tables