Thanks Jonathan, I have the cfstats but our prod team has changed some configs after my post and I do not have the cfhistograms information now.
No Of nodes: 3
Ram: 472GB
Cassandra version: 1.2.5
I am pasting the cfstats below.
Regards
Jay
CREATE TABLE "EnablerCreditReasonInfo" (
key text PRIMARY KEY,
"creditReasonDescription" text
) WITH COMPACT STORAGE AND
bloom_filter_fp_chance=0.010000 AND
caching='ROWS_ONLY' AND
comment='' AND
dclocal_read_repair_chance=0.000000 AND
gc_grace_seconds=864000 AND
read_repair_chance=0.100000 AND
replicate_on_write='true' AND
populate_io_cache_on_flush='false' AND
compaction={'class': 'SizeTieredCompactionStrategy'} AND
compression={'sstable_compression': 'SnappyCompressor'};
CFStats
Column Family: EnablerCreditReasonInfo
SSTable count: 3
Space used (live): 108067
Space used (total): 108067
Number of Keys (estimate): 1920
Memtable Columns Count: 0
Memtable Data Size: 0
Memtable Switch Count: 0
Read Count: 0
Read Latency: NaN ms.
Write Count: 0
Write Latency: NaN ms.
Pending Tasks: 0
Bloom Filter False Positives: 0
Bloom Filter False Ratio: 0.00000
Bloom Filter Space Used: 2232
Compacted row minimum size: 61
Compacted row maximum size: 149
Compacted row mean size: 100
From: Jonathan Lacefield [mailto:[email protected]]
Sent: Tuesday, February 11, 2014 10:43 AM
To: [email protected]
Subject: Re: Worse perf after Row Caching version 1.2.5:
Hello,
Please paste the output of cfhistograms for these tables. Also, what does
your environment look like, number of nodes, disk drive configs, memory, C*
version, etc.
Thanks,
Jonathan
Jonathan Lacefield
Solutions Architect, DataStax
(404) 822 3487
[Image removed by sender.]<http://www.linkedin.com/in/jlacefield>
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On Tue, Feb 11, 2014 at 10:26 AM, PARASHAR, BHASKARJYA JAY
<[email protected]<mailto:[email protected]>> wrote:
Hi,
I have two tables and I enabled row caching for both of them using CQL. These
two CF's are very small with one about 300 rows and other < 2000 rows. The rows
themselves are small.
Cassandra heap: 8gb.
a. alter table TABLE_X with caching = 'rows_only';
b. alter table TABLE_Y with caching = 'rows_only';
I also changed row_cache_size_in_mb: 1024 in the Cassandra.yaml file.
After extensive testing, it seems the performance of Table_X degraded from
600ms to 750ms and Table_Y gained about 10 ms (from 188ms to 177 ms).
More Info
Table X is always queried with "Select * from Table_X"; Cfstats in Table_X
shows Read Latency: NaN ms. I assumed that since we select all the rows, the
entire table would be cached.
Table_Y has a secondary index and is queried on that index.
Would appreciate any input why the performance is worse and how to enable row
caching for these two tables.
Thanks
Jay
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