Cassandra Read Timeout

[Yulian Oifa <oi...@gmail.com>]

Hello to all
I have single node cassandra on amazon ec2.
Currently i am having a read timeout problem on single CF , single raw.

Raw size is aroung 190MB.There are bigger raws with similar structure ( its
index raws , which actually stores keys ) and everything is working fine on
them, everything is working also fine on this cf but on other raw.

Tables data from CFStats ( First table has bigger raws but works fine ,
where second has timeout ) :
Column Family: pendindexes
SSTable count: 5
Space used (live): 462298352
Space used (total): 462306752
SSTable Compression Ratio: 0.3511107495795905
Number of Keys (estimate): 640
Memtable Columns Count: 63339
Memtable Data Size: 12328802
Memtable Switch Count: 78
Read Count: 10
Read Latency: NaN ms.
Write Count: 1530113
Write Latency: 0.022 ms.
Pending Tasks: 0
Bloom Filter False Positives: 0
Bloom Filter False Ratio: 0.00000
Bloom Filter Space Used: 3920
Compacted row minimum size: 73
Compacted row maximum size: 223875792
Compacted row mean size: 42694982
Average live cells per slice (last five minutes): 21.0
Average tombstones per slice (last five minutes): 0.0

Column Family: statuspindexes
SSTable count: 1
Space used (live): 99602136
Space used (total): 99609360
SSTable Compression Ratio: 0.34278775390997873
Number of Keys (estimate): 128
Memtable Columns Count: 6250
Memtable Data Size: 6061097
Memtable Switch Count: 65
Read Count: 1000
Read Latency: NaN ms.
Write Count: 1193142
Write Latency: 3.616 ms.
Pending Tasks: 0
Bloom Filter False Positives: 0
Bloom Filter False Ratio: 0.00000
Bloom Filter Space Used: 656
Compacted row minimum size: 180
Compacted row maximum size: 186563160
Compacted row mean size: 63225562
Average live cells per slice (last five minutes): 0.0
Average tombstones per slice (last five minutes): 0.0

I have tried to debug it with cql , thats what i get:

 activity
| timestamp    | source       | source_elapsed
-------------------------------------------------------------------------------------------------+--------------+--------------+----------------

execute_cql3_query | 15:39:53,120 | 172.31.6.173 |              0
                                               Parsing Select * from
statuspindexes LIMIT 10000; | 15:39:53,120 | 172.31.6.173 |            875

Preparing statement | 15:39:53,121 | 172.31.6.173 |           1643

Determining replicas to query | 15:39:53,121 | 172.31.6.173 |           1740
 Executing seq scan across 1 sstables for [min(-9223372036854775808),
min(-9223372036854775808)] | 15:39:53,122 | 172.31.6.173 |           2581
                                                     Seeking to partition
beginning in data file | 15:39:53,123 | 172.31.6.173 |           3118
                                           Timed out; received 0 of 1
responses for range 2 of 2 | 15:40:03,121 | 172.31.6.173 |       10001370

Request complete | 15:40:03,121 | 172.31.6.173 |       10001513

I have executed compaction on that cf.
What could lead to that problem?
Best regards
Yulian Oifa