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https://issues.apache.org/jira/browse/CASSANDRA-8646?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Nitin Padalia updated CASSANDRA-8646:
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Summary: Row Cache Miss with clustering key (was: For Column family )
> Row Cache Miss with clustering key
> ----------------------------------
>
> Key: CASSANDRA-8646
> URL: https://issues.apache.org/jira/browse/CASSANDRA-8646
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Environment: OS: CentOS 6.5, [cqlsh 5.0.1 | Cassandra 2.1.2 | CQL
> spec 3.2.0 | Native protocol v3]. Using CQL CLI for query analysis.
> Reporter: Nitin Padalia
> Priority: Minor
> Fix For: 2.1.2
>
>
> Cassandra doesn't hit row cache for first and last row of a partition if we
> mention cluster keys in where condition. However if we use limit then it hits
> the row cache for the same rows.
> E.G. I've a column family:
> CREATE TABLE ucxndirdb2.usertable_cache (
> user_id uuid,
> dept_id uuid,
> location_id text,
> locationmap_id uuid,
> PRIMARY KEY ((user_id, dept_id), location_id)
> ) WITH CLUSTERING ORDER BY (location_id ASC)
> AND bloom_filter_fp_chance = 0.01
> AND caching = '{"keys":"ALL", "rows_per_partition":"3"}'
> AND comment = ''
> AND compaction = {'min_threshold': '4', 'class':
> 'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy',
> 'max_threshold': '32'}
> 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';
> It has 3 rows per partition keys enabled for row cache.
> Now for a cached request, if I run:
> select * from usertable_cache WHERE user_id =
> 7bf16edf-b552-40f4-94ac-87b2e878d8c2 and dept_id =
> de3ac44f-2078-4321-a47c-de96c615d40d limit 3;
> Then its a cache hit with follow results:
> user_id | dept_id
> | location_id | locationmap_id
> --------------------------------------+--------------------------------------+-------------+--------------------------------------
> 7bf16edf-b552-40f4-94ac-87b2e878d8c2 | de3ac44f-2078-4321-a47c-de96c615d40d
> | ABC4:1 | 32b97639-ea5b-427f-8c27-8a5016e2ad6e
> 7bf16edf-b552-40f4-94ac-87b2e878d8c2 | de3ac44f-2078-4321-a47c-de96c615d40d
> | ABC4:10 | dfacc9fc-7a6a-4fb4-8a4f-c13c606d552b
> 7bf16edf-b552-40f4-94ac-87b2e878d8c2 | de3ac44f-2078-4321-a47c-de96c615d40d
> | ABC4:100 | 9ba7236a-6124-41c8-839b-edd299f510f7
> However If I run:
> select * from usertable_cache WHERE user_id =
> 7bf16edf-b552-40f4-94ac-87b2e878d8c2 and dept_id =
> de3ac44f-2078-4321-a47c-de96c615d40d and location_id = 'ABC4:1';
> or
> select * from usertable_cache WHERE user_id =
> 7bf16edf-b552-40f4-94ac-87b2e878d8c2 and dept_id =
> de3ac44f-2078-4321-a47c-de96c615d40d and location_id = 'ABC4:100';
> Then its a cache miss. However for following its hit for following
> select * from usertable_cache WHERE user_id =
> 7bf16edf-b552-40f4-94ac-87b2e878d8c2 and dept_id =
> de3ac44f-2078-4321-a47c-de96c615d40d and location_id = 'ABC4:10';
> and this behavior is consistent by increasing/decreasing rows_per_partiton
> setting. Cache is miss for only first and last record of the partition.
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