Caching not Working in Cassandra - caching

I dont seem to have any caching enabled when checking in Opscenter or cfstats. Im running Cassandra 1.1.7 with Solandra on Debian. I have set the required global options in cassandra.yaml:
key_cache_size_in_mb: 800
key_cache_save_period: 14400
row_cache_size_in_mb: 800
row_cache_save_period: 15400
row_cache_provider: SerializingCacheProvider
Column Families were created as follows:
create column family example
with column_type = 'Standard'
and comparator = 'BytesType'
and default_validation_class = 'BytesType'
and key_validation_class = 'BytesType'
and read_repair_chance = 1.0
and dclocal_read_repair_chance = 0.0
and gc_grace = 864000
and min_compaction_threshold = 4
and max_compaction_threshold = 32
and replicate_on_write = true
and compaction_strategy = 'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy'
and caching = 'ALL';
Opscenter shows no data available on caching graphs and CFSTATS doesn't show any cache related fields:
Column Family: charsets
SSTable count: 1
Space used (live): 5558
Space used (total): 5558
Number of Keys (estimate): 128
Memtable Columns Count: 0
Memtable Data Size: 0
Memtable Switch Count: 0
Read Count: 61381
Read Latency: 0.123 ms.
Write Count: 0
Write Latency: NaN ms.
Pending Tasks: 0
Bloom Filter False Postives: 0
Bloom Filter False Ratio: 0.00000
Bloom Filter Space Used: 16
Compacted row minimum size: 1917
Compacted row maximum size: 2299
Compacted row mean size: 2299
Any help or suggestions are appreciated.
Sam

The caching stats have been moved from cfstats to info in Cassandra 1.1. If you run nodetool info you should see something like:
Key Cache : size 5552 (bytes), capacity 838860800 (bytes), 38 hits, 47 requests, 0.809 recent hit rate, 14400 save period in seconds
Row Cache : size 0 (bytes), capacity 838860800 (bytes), 0 hits, 0 requests, NaN recent hit rate, 15400 save period in seconds
This is because there are now global caches, rather than per-CF. It seems that Opscenter needs updating for this change - maybe there is a later version available that will work.

Related

EHCache has too many misses on the heap tier

I am using a standalone EHcache 3.10 with heap tier, and disk tier.
The heap is configured to contain 100 entries with no expirations.
Actually, the algorithm insert only 30 entries into the cache, but it perform many "updates" and "reads" of these 30 entries.
Before I insert a new entry to the cache, there is a check if the entry already exist.
Therefore when I check ehcache statistics, I expect to see only 30 - misses on the heap tier, and 30 misses on the disk tier. But,
Instead I get 9806 misses on the heap tier, and 9806 hits on the disk tier. (Meaning 9806 times ehcache did not found the entry on the heap, but instead it was found on the disk)
These numbers make no sense to me, since the heap tier should contain 100 entries, so, why there are so many misses?
Here is my configuration:
statisticsService = new DefaultStatisticsService();
// create temp dir
Path cacheDirectory = getCacheDirectory();
ResourcePoolsBuilder resourcePoolsBuilder =
ResourcePoolsBuilder.newResourcePoolsBuilder()
.heap(100, EntryUnit.ENTRIES)
.disk(Long.MAX_VALUE, MemoryUnit.B, true)
;
CacheConfigurationBuilder cacheConfigurationBuilder =
CacheConfigurationBuilder.newCacheConfigurationBuilder(
String.class, // The cache key
ARFileImpl.class, // The cache value
resourcePoolsBuilder)
.withExpiry(ExpiryPolicyBuilder.noExpiration()) // No expiration
.withResilienceStrategy(new ThrowingResilienceStrategy<>())
.withSizeOfMaxObjectGraph(100000);
// Create the cache manager
cacheManager =
CacheManagerBuilder.newCacheManagerBuilder()
// Set the persistent directory
.with(CacheManagerBuilder.persistence(cacheDirectory.toFile()))
.withCache(ARFILE_CACHE_NAME, cacheConfigurationBuilder)
.using(statisticsService)
.build(true);
Here is the result of the statistics:
Cache stats:
CacheExpirations: 0
CacheEvictions: 0
CacheGets: 6669684
CacheHits: 6669684
CacheMisses: 0
CacheHitPercentage: 100.0
CacheMissPercentage: 0.0
CachePuts: 10525
CacheRemovals: 0
Heap stats:
AllocatedByteSize: -1
Mappings: 30
Evictions: 0
Expirations: 0
Hits: 6659878
Misses: 9806
OccupiedByteSize: -1
Puts: 0
Removals: 0
Disk stats:
AllocatedByteSize: 22429696
Mappings: 30
Evictions: 0
Expirations: 0
Hits: 9806
Misses: 0
OccupiedByteSize: 9961952
Puts: 10525
Removals: 0
The reason for asking this question is that there are a lot of redundant disk reads, which result with performance degradation.

Elasticsearch Slow as size parameter increases (not dependent on data size)

I have the following peculiar case for a simple GET request "query": {"match_all": {}},"sort": ["_doc"] with:
size = 0:
_source = ["X"]: 0.03 sec and 262 bytes
_source = ["X", "Y", "Z"]: 0.02 sec and 262 bytes
size = 10:
_source = ["X"]: 0.90 sec and 2944 bytes
_source = ["X", "Y", "Z"]: 0.88 sec and 949 Kb
size = 20:
_source = ["X"]: 1.20 sec and 5613 bytes
_source = ["X", "Y", "Z"]: 1.14 sec and 1006 Kb
size = 60:
_source = ["X"]: 2.30 sec and 9693 bytes
_source = ["X", "Y", "Z"]: 2.08 sec and 1120 Kb
The fields "X", "Y", "Z" are of type "text" and hold either years, either one / two words.
Seems to me that the increase in data size is not the problem of the slow query, but rather only the increase in size parameter.
For 1120Kb of data, it shouldn't take 2.5 seconds to retrieve the data - way too much.
I have an architecture of one cluster with one node and 5 indices. Each index has 1 shard allocated except for an index which has 2 shards.
RAM capacity is of 58GB and the heap size is 8GB.
The Elasticsearch version is 7.6
I already have:
request cache set to True
cache size equal to 20% of heap
preload of ["nvd", "dvd", "dvm", "doc"]
no explicit refresh
refresh_time of 2s on the index on which the queries are done
2 shards on on the index on which the queries are done
swap disabled
GET _cat/indices shows the heap is used 63% and the RAM is used 37% (it should be the other way around)
GET index/_settings shows the fetch phase is 76 times bigger than the query phase! (~2.3s vs 0.03s)
Where could the problem be?
Thanks in advance.

Can't add node to the cockroachde cluster

I'm staking to join a CockroachDB node to a cluster.
I've created first cluster, then try to join 2nd node to the first node, but 2nd node created new cluster as follows.
Does anyone knows whats are wrong steps on the following my steps, any suggestions are wellcome.
I've started first node as follows:
cockroach start --insecure --advertise-host=163.172.156.111
* Check out how to secure your cluster: https://www.cockroachlabs.com/docs/v19.1/secure-a-cluster.html
*
CockroachDB node starting at 2019-05-11 01:11:15.45522036 +0000 UTC (took 2.5s)
build: CCL v19.1.0 # 2019/04/29 18:36:40 (go1.11.6)
webui: http://163.172.156.111:8080
sql: postgresql://root#163.172.156.111:26257?sslmode=disable
client flags: cockroach <client cmd> --host=163.172.156.111:26257 --insecure
logs: /home/ueda/cockroach-data/logs
temp dir: /home/ueda/cockroach-data/cockroach-temp449555924
external I/O path: /home/ueda/cockroach-data/extern
store[0]: path=/home/ueda/cockroach-data
status: initialized new cluster
clusterID: 3e797faa-59a1-4b0d-83b5-36143ddbdd69
nodeID: 1
Then, start secondary node to join to 163.172.156.111, but can't join:
cockroach start --insecure --advertise-addr=128.199.127.164 --join=163.172.156.111:26257
CockroachDB node starting at 2019-05-11 01:21:14.533097432 +0000 UTC (took 0.8s)
build: CCL v19.1.0 # 2019/04/29 18:36:40 (go1.11.6)
webui: http://128.199.127.164:8080
sql: postgresql://root#128.199.127.164:26257?sslmode=disable
client flags: cockroach <client cmd> --host=128.199.127.164:26257 --insecure
logs: /home/ueda/cockroach-data/logs
temp dir: /home/ueda/cockroach-data/cockroach-temp067740997
external I/O path: /home/ueda/cockroach-data/extern
store[0]: path=/home/ueda/cockroach-data
status: restarted pre-existing node
clusterID: a14e89a7-792d-44d3-89af-7037442eacbc
nodeID: 1
The cockroach.log of joining node shows some gosip error:
cat cockroach-data/logs/cockroach.log
I190511 01:21:13.762309 1 util/log/clog.go:1199 [config] file created at: 2019/05/11 01:21:13
I190511 01:21:13.762309 1 util/log/clog.go:1199 [config] running on machine: amfortas
I190511 01:21:13.762309 1 util/log/clog.go:1199 [config] binary: CockroachDB CCL v19.1.0 (x86_64-unknown-linux-gnu, built 2019/04/29 18:36:40, go1.11.6)
I190511 01:21:13.762309 1 util/log/clog.go:1199 [config] arguments: [cockroach start --insecure --advertise-addr=128.199.127.164 --join=163.172.156.111:26257]
I190511 01:21:13.762309 1 util/log/clog.go:1199 line format: [IWEF]yymmdd hh:mm:ss.uuuuuu goid file:line msg utf8=✓
I190511 01:21:13.762307 1 cli/start.go:1033 logging to directory /home/ueda/cockroach-data/logs
W190511 01:21:13.763373 1 cli/start.go:1068 RUNNING IN INSECURE MODE!
- Your cluster is open for any client that can access <all your IP addresses>.
- Any user, even root, can log in without providing a password.
- Any user, connecting as root, can read or write any data in your cluster.
- There is no network encryption nor authentication, and thus no confidentiality.
Check out how to secure your cluster: https://www.cockroachlabs.com/docs/v19.1/secure-a-cluster.html
I190511 01:21:13.763675 1 server/status/recorder.go:610 available memory from cgroups (8.0 EiB) exceeds system memory 992 MiB, using system memory
W190511 01:21:13.763752 1 cli/start.go:944 Using the default setting for --cache (128 MiB).
A significantly larger value is usually needed for good performance.
If you have a dedicated server a reasonable setting is --cache=.25 (248 MiB).
I190511 01:21:13.764011 1 server/status/recorder.go:610 available memory from cgroups (8.0 EiB) exceeds system memory 992 MiB, using system memory
W190511 01:21:13.764047 1 cli/start.go:957 Using the default setting for --max-sql-memory (128 MiB).
A significantly larger value is usually needed in production.
If you have a dedicated server a reasonable setting is --max-sql-memory=.25 (248 MiB).
I190511 01:21:13.764239 1 server/status/recorder.go:610 available memory from cgroups (8.0 EiB) exceeds system memory 992 MiB, using system memory
I190511 01:21:13.764272 1 cli/start.go:1082 CockroachDB CCL v19.1.0 (x86_64-unknown-linux-gnu, built 2019/04/29 18:36:40, go1.11.6)
I190511 01:21:13.866977 1 server/status/recorder.go:610 available memory from cgroups (8.0 EiB) exceeds system memory 992 MiB, using system memory
I190511 01:21:13.867002 1 server/config.go:386 system total memory: 992 MiB
I190511 01:21:13.867063 1 server/config.go:388 server configuration:
max offset 500000000
cache size 128 MiB
SQL memory pool size 128 MiB
scan interval 10m0s
scan min idle time 10ms
scan max idle time 1s
event log enabled true
I190511 01:21:13.867098 1 cli/start.go:929 process identity: uid 1000 euid 1000 gid 1000 egid 1000
I190511 01:21:13.867115 1 cli/start.go:554 starting cockroach node
I190511 01:21:13.868242 21 storage/engine/rocksdb.go:613 opening rocksdb instance at "/home/ueda/cockroach-data/cockroach-temp067740997"
I190511 01:21:13.894320 21 server/server.go:876 [n?] monitoring forward clock jumps based on server.clock.forward_jump_check_enabled
I190511 01:21:13.894813 21 storage/engine/rocksdb.go:613 opening rocksdb instance at "/home/ueda/cockroach-data"
W190511 01:21:13.896301 21 storage/engine/rocksdb.go:127 [rocksdb] [/go/src/github.com/cockroachdb/cockroach/c-deps/rocksdb/db/version_set.cc:2566] More existing levels in DB than needed. max_bytes_for_level_multiplier may not be guaranteed.
W190511 01:21:13.905666 21 storage/engine/rocksdb.go:127 [rocksdb] [/go/src/github.com/cockroachdb/cockroach/c-deps/rocksdb/db/version_set.cc:2566] More existing levels in DB than needed. max_bytes_for_level_multiplier may not be guaranteed.
I190511 01:21:13.911380 21 server/config.go:494 [n?] 1 storage engine initialized
I190511 01:21:13.911417 21 server/config.go:497 [n?] RocksDB cache size: 128 MiB
I190511 01:21:13.911427 21 server/config.go:497 [n?] store 0: RocksDB, max size 0 B, max open file limit 10000
W190511 01:21:13.912459 21 gossip/gossip.go:1496 [n?] no incoming or outgoing connections
I190511 01:21:13.913206 21 server/server.go:926 [n?] Sleeping till wall time 1557537673913178595 to catches up to 1557537674394265598 to ensure monotonicity. Delta: 481.087003ms
I190511 01:21:14.251655 65 vendor/github.com/cockroachdb/circuitbreaker/circuitbreaker.go:322 [n?] circuitbreaker: gossip [::]:26257->163.172.156.111:26257 tripped: initial connection heartbeat failed: rpc error: code = Unknown desc = client cluster ID "a14e89a7-792d-44d3-89af-7037442eacbc" doesn't match server cluster ID "3e797faa-59a1-4b0d-83b5-36143ddbdd69"
I190511 01:21:14.251695 65 vendor/github.com/cockroachdb/circuitbreaker/circuitbreaker.go:447 [n?] circuitbreaker: gossip [::]:26257->163.172.156.111:26257 event: BreakerTripped
W190511 01:21:14.251763 65 gossip/client.go:122 [n?] failed to start gossip client to 163.172.156.111:26257: initial connection heartbeat failed: rpc error: code = Unknown desc = client cluster ID "a14e89a7-792d-44d3-89af-7037442eacbc" doesn't match server cluster ID "3e797faa-59a1-4b0d-83b5-36143ddbdd69"
I190511 01:21:14.395848 21 gossip/gossip.go:392 [n1] NodeDescriptor set to node_id:1 address:<network_field:"tcp" address_field:"128.199.127.164:26257" > attrs:<> locality:<> ServerVersion:<major_val:19 minor_val:1 patch:0 unstable:0 > build_tag:"v19.1.0" started_at:1557537674395557548
W190511 01:21:14.458176 21 storage/replica_range_lease.go:506 can't determine lease status due to node liveness error: node not in the liveness table
I190511 01:21:14.458465 21 server/node.go:461 [n1] initialized store [n1,s1]: disk (capacity=24 GiB, available=18 GiB, used=2.2 MiB, logicalBytes=41 MiB), ranges=20, leases=0, queries=0.00, writes=0.00, bytesPerReplica={p10=0.00 p25=0.00 p50=0.00 p75=6467.00 p90=26940.00 pMax=43017435.00}, writesPerReplica={p10=0.00 p25=0.00 p50=0.00 p75=0.00 p90=0.00 pMax=0.00}
I190511 01:21:14.458775 21 storage/stores.go:244 [n1] read 0 node addresses from persistent storage
I190511 01:21:14.459095 21 server/node.go:699 [n1] connecting to gossip network to verify cluster ID...
W190511 01:21:14.469842 96 storage/store.go:1525 [n1,s1,r6/1:/Table/{SystemCon…-11}] could not gossip system config: [NotLeaseHolderError] r6: replica (n1,s1):1 not lease holder; lease holder unknown
I190511 01:21:14.474785 21 server/node.go:719 [n1] node connected via gossip and verified as part of cluster "a14e89a7-792d-44d3-89af-7037442eacbc"
I190511 01:21:14.475033 21 server/node.go:542 [n1] node=1: started with [<no-attributes>=/home/ueda/cockroach-data] engine(s) and attributes []
I190511 01:21:14.475393 21 server/status/recorder.go:610 [n1] available memory from cgroups (8.0 EiB) exceeds system memory 992 MiB, using system memory
I190511 01:21:14.475514 21 server/server.go:1582 [n1] starting http server at [::]:8080 (use: 128.199.127.164:8080)
I190511 01:21:14.475572 21 server/server.go:1584 [n1] starting grpc/postgres server at [::]:26257
I190511 01:21:14.475605 21 server/server.go:1585 [n1] advertising CockroachDB node at 128.199.127.164:26257
W190511 01:21:14.475655 21 jobs/registry.go:341 [n1] unable to get node liveness: node not in the liveness table
I190511 01:21:14.532949 21 server/server.go:1650 [n1] done ensuring all necessary migrations have run
I190511 01:21:14.533020 21 server/server.go:1653 [n1] serving sql connections
I190511 01:21:14.533209 21 cli/start.go:689 [config] clusterID: a14e89a7-792d-44d3-89af-7037442eacbc
I190511 01:21:14.533257 21 cli/start.go:697 node startup completed:
CockroachDB node starting at 2019-05-11 01:21:14.533097432 +0000 UTC (took 0.8s)
build: CCL v19.1.0 # 2019/04/29 18:36:40 (go1.11.6)
webui: http://128.199.127.164:8080
sql: postgresql://root#128.199.127.164:26257?sslmode=disable
client flags: cockroach <client cmd> --host=128.199.127.164:26257 --insecure
logs: /home/ueda/cockroach-data/logs
temp dir: /home/ueda/cockroach-data/cockroach-temp067740997
external I/O path: /home/ueda/cockroach-data/extern
store[0]: path=/home/ueda/cockroach-data
status: restarted pre-existing node
clusterID: a14e89a7-792d-44d3-89af-7037442eacbc
nodeID: 1
I190511 01:21:14.541205 146 server/server_update.go:67 [n1] no need to upgrade, cluster already at the newest version
I190511 01:21:14.555557 149 sql/event_log.go:135 [n1] Event: "node_restart", target: 1, info: {Descriptor:{NodeID:1 Address:128.199.127.164:26257 Attrs: Locality: ServerVersion:19.1 BuildTag:v19.1.0 StartedAt:1557537674395557548 LocalityAddress:[] XXX_NoUnkeyedLiteral:{} XXX_sizecache:0} ClusterID:a14e89a7-792d-44d3-89af-7037442eacbc StartedAt:1557537674395557548 LastUp:1557537671113461486}
I190511 01:21:14.916458 59 gossip/gossip.go:1510 [n1] node has connected to cluster via gossip
I190511 01:21:14.916660 59 storage/stores.go:263 [n1] wrote 0 node addresses to persistent storage
I190511 01:21:24.480247 116 storage/store.go:4220 [n1,s1] sstables (read amplification = 2):
0 [ 51K 1 ]: 51K
6 [ 1M 1 ]: 1M
I190511 01:21:24.480380 116 storage/store.go:4221 [n1,s1]
** Compaction Stats [default] **
Level Files Size Score Read(GB) Rn(GB) Rnp1(GB) Write(GB) Wnew(GB) Moved(GB) W-Amp Rd(MB/s) Wr(MB/s) Comp(sec) Comp(cnt) Avg(sec) KeyIn KeyDrop
----------------------------------------------------------------------------------------------------------------------------------------------------------
L0 1/0 50.73 KB 0.5 0.0 0.0 0.0 0.0 0.0 0.0 1.0 0.0 8.0 0 1 0.006 0 0
L6 1/0 1.26 MB 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 0.000 0 0
Sum 2/0 1.31 MB 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.0 0.0 8.0 0 1 0.006 0 0
Int 0/0 0.00 KB 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.0 0.0 8.0 0 1 0.006 0 0
Uptime(secs): 10.6 total, 10.6 interval
Flush(GB): cumulative 0.000, interval 0.000
AddFile(GB): cumulative 0.000, interval 0.000
AddFile(Total Files): cumulative 0, interval 0
AddFile(L0 Files): cumulative 0, interval 0
AddFile(Keys): cumulative 0, interval 0
Cumulative compaction: 0.00 GB write, 0.00 MB/s write, 0.00 GB read, 0.00 MB/s read, 0.0 seconds
Interval compaction: 0.00 GB write, 0.00 MB/s write, 0.00 GB read, 0.00 MB/s read, 0.0 seconds
Stalls(count): 0 level0_slowdown, 0 level0_slowdown_with_compaction, 0 level0_numfiles, 0 level0_numfiles_with_compaction, 0 stop for pending_compaction_bytes, 0 slowdown for pending_compaction_bytes, 0 memtable_compaction, 0 memtable_slowdown, interval 0 total count
estimated_pending_compaction_bytes: 0 B
I190511 01:21:24.481565 121 server/status/runtime.go:500 [n1] runtime stats: 170 MiB RSS, 114 goroutines, 0 B/0 B/0 B GO alloc/idle/total, 14 MiB/16 MiB CGO alloc/total, 0.0 CGO/sec, 0.0/0.0 %(u/s)time, 0.0 %gc (7x), 50 KiB/1.5 MiB (r/w)net
What is the possibly cause to block to join? Thank you for your suggestion!
It seems you had previously started the second node (the one running on 128.199.127.164) by itself, creating its own cluster.
This can be seen in the error message:
W190511 01:21:14.251763 65 gossip/client.go:122 [n?] failed to start gossip client to 163.172.156.111:26257: initial connection heartbeat failed: rpc error: code = Unknown desc = client cluster ID "a14e89a7-792d-44d3-89af-7037442eacbc" doesn't match server cluster ID "3e797faa-59a1-4b0d-83b5-36143ddbdd69"
To be able to join the cluster, the data directory of the joining node must be empty. You can either delete cockroach-data or specify an alternate directory with --store=/path/to/data-dir

Ehcache miss counts

These are the statistics for my Ehcache.
I have it configured to use only memory (no persistence, no overflow to disk).
cacheHits = 50
onDiskHits = 0
offHeapHits = 0
inMemoryHits = 50
misses = 1194
onDiskMisses = 0
offHeapMisses = 0
inMemoryMisses = 1138
size = 69
averageGetTime = 0.061597
evictionCount = 0
As you can see, misses is higher than onDiskMisses + offHeapMisses + inMemoryMisses. I do have statistics strategy set to best effort:
cache.setStatisticsAccuracy(Statistics.STATISTICS_ACCURACY_BEST_EFFORT)
But the hits add up, and the difference between misses is rather large. Is there a reason why the misses do not add up correctly?
This quesiton is similar to Ehcache misses count and hitrate statistics, but the answer attributes the differences to the multiple tiers. There is only one tier here.
I'm almost certain that you're seeing this because inMemoryMisses does not include misses due to expired elements. On a get if the value is stored, but expired then you will not see an inMemoryMiss recorded, but you will see a cache miss.

Cassandra read latency high even with row caching, why?

I am testing cassandra performance with a simple model.
CREATE TABLE "NoCache" (
key ascii,
column1 ascii,
value ascii,
PRIMARY KEY (key, column1)
) WITH COMPACT STORAGE AND
bloom_filter_fp_chance=0.010000 AND
caching='ALL' 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'};
I am fetching 100 columns of a row key using pycassa, get/xget function (). but getting read latency about 15ms in the server.
colums=COL_FAM.get(row_key, column_count=100)
nodetool cfstats
Column Family: NoCache
SSTable count: 1
Space used (live): 103756053
Space used (total): 103756053
Number of Keys (estimate): 128
Memtable Columns Count: 0
Memtable Data Size: 0
Memtable Switch Count: 0
Read Count: 20
Read Latency: 15.717 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: 976
Compacted row minimum size: 4769
Compacted row maximum size: 557074610
Compacted row mean size: 87979499
Latency of this type is amazing! When nodetool info shows that read hits directly in the row cache.
Row Cache : size 4834713 (bytes), capacity 67108864 (bytes), 35 hits, 38 requests, 1.000 recent hit rate, 0 save period in seconds
Can anyone tell me why is cassandra taking so much time while reading from row cache?
Enable tracing and see what it's doing. http://www.datastax.com/dev/blog/tracing-in-cassandra-1-2

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