Yulian, Maybe other people have other clues, but I think if you could monitor the behavior in tpstats after activity "Seeking to partition beginning in data file" it could help to find the problem. Which type of thread is getting stuck? Do you see any number increasing continuously during the request?
Best regards, Marcelo. From: user@cassandra.apache.org Subject: Re:Cassandra Read Timeout 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