Search code examples
cassandracassandra-2.0cql3

Range query on secondary index in cassandra


I am using cassandra 2.1.10. So First I will clear that I know secondary index are anti-pattern in cassandra.But for testing purpose I was trying following:

CREATE TABLE test_topology1.tt (
    a text PRIMARY KEY,
    b timestamp
) WITH bloom_filter_fp_chance = 0.01
    AND caching = '{"keys":"ALL", "rows_per_partition":"NONE"}'
    AND comment = ''
    AND compaction = {'class': 'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy'}
    AND compression = {'sstable_compression': 'org.apache.cassandra.io.compress.LZ4Compressor'}
    AND dclocal_read_repair_chance = 0.1
    AND default_time_to_live = 0
    AND gc_grace_seconds = 864000
    AND max_index_interval = 2048
    AND memtable_flush_period_in_ms = 0
    AND min_index_interval = 128
    AND read_repair_chance = 0.0
    AND speculative_retry = '99.0PERCENTILE';
CREATE INDEX idx_tt ON test_topology1.tt (b);

When I run following query it gives me error.

cqlsh:test_topology1> Select * from tt where b>='2016-04-29 18:00:00' ALLOW FILTERING;
InvalidRequest: code=2200 [Invalid query] message="No secondary indexes on the restricted columns support the provided operators: 'b >= <value>'"

while this Blog says that allow filtering can be used to query secondary index. Cassandra is installed on windows machine.


Solution

  • Range queries on secondary index columns are not allowed in Cassandra up to and including 2.2.x. However, as the post A deep look at the CQL WHERE clause points out, they are allowed on non-indexed columns, if filtering is allwed:

    Direct queries on secondary indices support only =, CONTAINS or CONTAINS KEY restrictions.

    [..]

    Secondary index queries allow you to restrict the returned results using the =, >, >=, <= and <, CONTAINS and CONTAINS KEY restrictions on non-indexed columns using filtering.

    So, given the table structure and index

    CREATE TABLE test_secondary_index (
         a text PRIMARY KEY,
         b timestamp,
         c timestamp 
    );
    CREATE INDEX idx_inequality_test ON test_secondary_index (b);
    

    the following query fails because the inequality test is done on the indexed column:

    SELECT * FROM  test_secondary_index WHERE b >= '2016-04-29 18:00:00' ALLOW FILTERING ;
    InvalidRequest: code=2200 [Invalid query] message="No secondary indexes on the restricted columns support the provided operators: 'b >= <value>'"
    

    But the following works because the inequality test is done on a non-indexed column:

    SELECT * FROM  test_secondary_index WHERE b = '2016-04-29 18:00:00' AND c >= '2016-04-29 18:00:00' ALLOW FILTERING ;
    
     a | b | c
    ---+---+---
    
    (0 rows)
    

    This still works if you add another index on column c, but also still requires the ALLOW FILTERING term, which to me means that the index on column c is not used in this scenario.