Seems like it’s probably worth opening a jira issue to track it (either to confirm it’s a bug, or to be able to better explain if/that it’s working as intended – the row cache is probably missing because trace indicates the read isn’t cacheable, but I suspect it should be cacheable).

                                                                                                                                                                                                                                           

Do note, though, that setting rows_per_partition to ALL can be very very very dangerous if you have very wide rows in any of your tables with row cache enabled.

 

 

 

From: Abhinav Solan <abhinav.solan@gmail.com>
Reply-To: "user@cassandra.apache.org" <user@cassandra.apache.org>
Date: Monday, October 3, 2016 at 1:38 PM
To: "user@cassandra.apache.org" <user@cassandra.apache.org>
Subject: Re: Row cache not working

 

It's cassandra 3.0.7, 

I had to set caching = {'keys': 'ALL', 'rows_per_partition': 'ALL'}, then only it works don't know why.

If I set 'rows_per_partition':'1' then it does not work.

 

Also wanted to ask one thing, if I set row_cache_save_period: 60 then this cache would be refreshed automatically or it would be lazy, whenever the fetch call is made then only it caches it.

 

On Mon, Oct 3, 2016 at 1:31 PM Jeff Jirsa <jeff.jirsa@crowdstrike.com> wrote:

Which version of Cassandra are you running (I can tell it’s newer than 2.1, but exact version would be useful)?

 

From: Abhinav Solan <abhinav.solan@gmail.com>
Reply-To: "user@cassandra.apache.org" <user@cassandra.apache.org>
Date: Monday, October 3, 2016 at 11:35 AM
To: "user@cassandra.apache.org" <user@cassandra.apache.org>
Subject: Re: Row cache not working

 

Hi, can anyone please help me with this

 

Thanks,

Abhinav

 

On Fri, Sep 30, 2016 at 6:20 PM Abhinav Solan <abhinav.solan@gmail.com> wrote:

Hi Everyone,

 

My table looks like this -

CREATE TABLE test.reads (

    svc_pt_id bigint,

    meas_type_id bigint,

    flags bigint,

    read_time timestamp,

    value double,

    PRIMARY KEY ((svc_pt_id, meas_type_id))

) WITH bloom_filter_fp_chance = 0.1

    AND caching = {'keys': 'ALL', 'rows_per_partition': '10'}

    AND comment = ''

    AND compaction = {'class': 'org.apache.cassandra.db.compaction.LeveledCompactionStrategy'}

    AND compression = {'chunk_length_in_kb': '64', 'class': 'org.apache.cassandra.io.compress.LZ4Compressor'}

    AND crc_check_chance = 1.0

    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 = '99PERCENTILE';

 

Have set up the C* nodes with

row_cache_size_in_mb: 1024

row_cache_save_period: 14400

 

and I am making this query 

select svc_pt_id, meas_type_id, read_time, value FROM cts_svc_pt_latest_int_read where svc_pt_id = -9941235 and meas_type_id = 146;

 

with tracing on every time it says Row cache miss

 

activity                                                                                                                                                          | timestamp                  | source          | source_elapsed

-------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------------+-----------------+----------------

                                                                                                                                                Execute CQL3 query | 2016-09-30 18:15:00.446000 |  192.168.199.75 |              0

 Parsing select svc_pt_id, meas_type_id, read_time, value FROM cts_svc_pt_latest_int_read where svc_pt_id = -9941235 and meas_type_id = 146; [SharedPool-Worker-1] | 2016-09-30 18:15:00.446000 |  192.168.199.75 |            111

                                                                                                                         Preparing statement [SharedPool-Worker-1] | 2016-09-30 18:15:00.446000 |  192.168.199.75 |            209

                                                                                                          reading data from /192.168.170.186 [SharedPool-Worker-1] | 2016-09-30 18:15:00.446001 |  192.168.199.75 |            370

                                                                             Sending READ message to /192.168.170.186 [MessagingService-Outgoing-/192.168.170.186] | 2016-09-30 18:15:00.446001 |  192.168.199.75 |            450

                                                              REQUEST_RESPONSE message received from /192.168.170.186 [MessagingService-Incoming-/192.168.170.186] | 2016-09-30 18:15:00.448000 |  192.168.199.75 |           2469

                                                                                                   Processing response from /192.168.170.186 [SharedPool-Worker-8] | 2016-09-30 18:15:00.448000 |  192.168.199.75 |           2609

                                                                            READ message received from /192.168.199.75 [MessagingService-Incoming-/192.168.199.75] | 2016-09-30 18:15:00.449000 | 192.168.170.186 |             75

                                                                                                                              Row cache miss [SharedPool-Worker-2] | 2016-09-30 18:15:00.449000 | 192.168.170.186 |            218

                                              Fetching data but not populating cache as query does not query from the start of the partition [SharedPool-Worker-2] | 2016-09-30 18:15:00.449000 | 192.168.170.186 |            246

                                                                              Executing single-partition query on cts_svc_pt_latest_int_read [SharedPool-Worker-2] | 2016-09-30 18:15:00.449000 | 192.168.170.186 |            259

                                                                                                                Acquiring sstable references [SharedPool-Worker-2] | 2016-09-30 18:15:00.449001 | 192.168.170.186 |            281

                                                                                                                   Merging memtable contents [SharedPool-Worker-2] | 2016-09-30 18:15:00.449001 | 192.168.170.186 |            295

                                                                                                                 Merging data from sstable 8 [SharedPool-Worker-2] | 2016-09-30 18:15:00.449001 | 192.168.170.186 |            326

                                                                                                                 Key cache hit for sstable 8 [SharedPool-Worker-2] | 2016-09-30 18:15:00.449001 | 192.168.170.186 |            351

                                                                                                                 Merging data from sstable 7 [SharedPool-Worker-2] | 2016-09-30 18:15:00.449001 | 192.168.170.186 |            439

                                                                                                                 Key cache hit for sstable 7 [SharedPool-Worker-2] | 2016-09-30 18:15:00.449001 | 192.168.170.186 |            468

                                                                                                           Read 1 live and 0 tombstone cells [SharedPool-Worker-2] | 2016-09-30 18:15:00.449001 | 192.168.170.186 |            615

                                                                                                       Enqueuing response to /192.168.199.75 [SharedPool-Worker-2] | 2016-09-30 18:15:00.449002 | 192.168.170.186 |            766

                                                                   Sending REQUEST_RESPONSE message to /192.168.199.75 [MessagingService-Outgoing-/192.168.199.75] | 2016-09-30 18:15:00.449002 | 192.168.170.186 |            897

                                                                                                                                                  Request complete | 2016-09-30 18:15:00.448888 |  192.168.199.75 |           2888

 

Can please anyone tell me what I am doing wrong?

 

Thanks,

Abhinav

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