[CASSANDRA-8871] Non-null paging state returned if last page

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Not A Problem

Environment

ruby-driver 2.1.0 | C* 2.0.12 | C* 2.1.3

• Severity: Normal
• Assignee: Tom Hobbs
• Reporter: Kishan Karunaratne

Authors

Tom Hobbs

• Created: 26/Feb/15 18:55
• Updated: 16/Apr/19 09:31
• Resolved: 28/Feb/15 00:00

Description

When retrieving the next page from the result of a simple statement, the result will return a non-null paging state even if it's the last page of the query. This only happens if it's the last page, and the results of the last page exactly matches the paging size.

Schema:

      CREATE KEYSPACE simplex WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 3};
      USE simplex;
      CREATE TABLE test (k text, v int, PRIMARY KEY (k, v));
      INSERT INTO test (k, v) VALUES ('a', 0);
      INSERT INTO test (k, v) VALUES ('b', 1);
      INSERT INTO test (k, v) VALUES ('c', 2);
      INSERT INTO test (k, v) VALUES ('d', 3);
      INSERT INTO test (k, v) VALUES ('e', 4);

Query:

      result  = session.execute("SELECT * FROM test", page_size: 5)

      loop do
        puts "last page? #{result.last_page?}"
        puts "page size: #{result.size}"

        result.each do |row|
          puts row
        end
        puts ""

        break if result.last_page?
        result = result.next_page
      end

Result:

      last page? false
      page size: 5
      {"k"=>"a", "v"=>0}
      {"k"=>"c", "v"=>2}
      {"k"=>"m", "v"=>12}
      {"k"=>"f", "v"=>5}
      {"k"=>"o", "v"=>14}
      
      last page? true
      page size: 0

Issue Links

• is related to: CASSANDRA-7120 Bad paging state returned for prepared statements for last page